Erratic throttle response when cold

[HPsauce]

I'm still trying to get a good feel for what goes on and when, but this is what I've noticed so far - more than once in each case:

1. Driving away from my house when starting the car from cold usually involves reversing out then driving off uphill, a definite hill but not especially steep.
I've noticed the car surging then slowing then surging forward again without me changing the position of my right foot. "Kangaroo petrol" :tuttut:
(I may have experienced this elsewhere but not 100% sure as I'm usually driving away gently on level ground)

2. Pulling out of a side road and accelerating the car only speeds up "gently" not "urgently" as I expect. No ABS/ESP warnings or symptoms. Only seen within the first minute or so of driving the car and not always by any means.

I haven't yet tried starting it on the drive and gently pressing the accelerator pedal to see if revs vary.

Problem #1 is a bit weird but #2 is potentially quite dangerous.

No codes showing on VCDS. No "slipping" or increased revs, just varying power so I suspect engine-related not gearbox.

It's an FL S8 which I understand is "fly-by-wire" though what the relevant components are and where I don't know.

Suggestions please on possible causes and how to diagnose.

[Architex_mA8tey]

have you checked that your manifold flaps and actuators aren't sticking and are operating properly? just a thought. . .

[HPsauce]

Pretty sure, I checked the other day (as noted somewhere here when I first got similar symptoms) and the links are definitely connected properly and the vacuum units operate as they should.

What can you check easily other than position when off and when started - they certainly move instantly.

[HPsauce]

A little more input on this problem.
It's been suggested that it might be a temperature sensor somewhere playing up and causing under-fuelling, so to try just leaving the car to idle and warm up somewhat before driving off. Then when it's cold again plug in VCDS and look for suspicious readings.

Did the idle warm-up this morning not touching the pedal, letting the needle move to about 60C before driving off; it behaved perfectly.

Though I have VCDS I wouldn't know where to start looking for sensors that can be checked, or which ones are likely culprits? Help! :o

[ainarssems]

Check engine temperature when it's cold if it shows much more them ambient the clearly it is wrong.

[HPsauce]

Well yes, but apart from the gauge on the dash (which seems to operate normally and has 50C at the bottom) where would I go (in VCDS?) for a more accurate figure? ;)

[ainarssems]

Measuring blocks and cycle through the channels to see different readings

[HPsauce]

OK, I'm with you, didn't realise it would explain what the measurements were. Haven't explored VCDS much so I'm a novice.:o

Did that and found nothing that looked odd, temp 15C about 3 hours after last use in 3C ambient which seems very plausible.

Started the engine and watched various measurements as it warmed up; again nothing looked odd to my inexperienced eyes. Though it did feel a bit "lumpy" when I revved it up to get it warm.

I think I might need to set it up to graph the throttle position among other things and go for a drive (with an assistant).

[HPsauce]

Any further thoughts anyone on a systematic way to investigate this and nail it down? It's getting annoying. :tuttut:

I went for a short drive yesterday, starting off by "pootling" down the road (250yds downhill) and turning left into the main road at the bottom.
Luckily it's only a 30mph limit as at the first attempt it just dawdled, so I didn't pull out. :angry2:
Second go a few seconds later was fine and I then turned on cruise control for most of my journey which is in a 50mph limit.
After a 2-mile drive it was parked for maybe 30-40 minutes then started up and driven home - no dramas at all, behaved normally.

Checked codes today and there's only the intermittent 01119 Gear Recognition Signal problem in ABS (03). Could that be in any way related? :Confused:

[Architex_mA8tey]

are all the breather pipes in good order and not leaking anywhere? just a thought as it sometimes causes lumpy running etc. . .

[Architex_mA8tey]

the 01119 error is normally dirty ABS sensors - Sergey had that particular problem a couple of years ago - see HERE (http://forum.a8parts.co.uk/showthread.php?t=1871) +++
so it shouldnt be related to the other lumpy running.

[HPsauce]

Yes I mentioned it (01119) before, just haven't dealt with it yet :o .

It's not lumpy, more "kangaroo" as the throttle either works normally or hardly works at all until you floor it. And sometimes it changes (surges) without moving my foot. But only at the start of a journey from cold, well as far as I can tell.

[PsYcHe]

Do you have traction control?

ABS sensor issues could cause that to freak out.. Does the light flash when the car is unresponsive?

[HPsauce]

I thought of that too, and no it doesn't, nor does the engine rev. It's as if pressing the throttle is ignored then randomly sensed.

I've not been able to do it enough in "safe, controlled" circumstances to get any more analysis. Leaving my house which is on the corner of a side road off a bend on a narrow built-up road on a hill with lots of parked cars around is far from the ideal spot. :ROFL:

[HPsauce]

Had a little play on the drive today with VCDS and I'm none the wiser. :Confused:
Set up to monitor the throttle position and pedal sensors (Engine, block 62) and a few other things such as air flow.
First, with ignition on but engine not running the pedal & throttle sensors all seemed to vary sensibly and smoothly.
Same after starting the car, everything seemed to vary smoothly as I moved the pedal up and down.

That said I haven't noticed the problem for a few days either. The only recent variation is that I have Tesco Momentum in the tank; it's usually Shell "cooking" 95RON. Could that be a factor?

I did check for codes and the only one was an engine coolant high temp warning, which I've never seen before. Possibly from some "spirited" driving to/from the Forest of Dean on Sunday. :ROFL:

[HPsauce]

A little update on this, the problem reappeared twice yesterday evening near the start of a short run. Just significant lack of power for a few seconds, no other symptoms. :Confused:

I replaced the coolant temperature sensor (it was suspect) a while back and have been running exclusively on Shell V-Power Nitro+ for some time and all has been fine.

Checked the codes today and the 01119 Gear Recognition Signal (intermittent) was there again, but nothing else. It's about 3 months since I last checked.

The Ross-Tech Wiki just says 01119 is a note and to refer to the TCM/J217 for detailed codes. I presume that means 02 Transmission in VCDS or is it something more detailed I need to get at?

A document I found online also says that intermittent codes will clear quickly, so do I need to stop ASAP after an "event" and plug the laptop in?
Malfunctions that are stored in DTC Memory as sporadic malfunctions are automatically erased after 1,000 km (600 miles) or 20 hours.
Though neither 1000km or 20 hours have elapsed since it misbehaved yesterday, so maybe the 01119 is not connected to the lack of power?

[notorious]

Will use premium petrol first, like Shell Nitro. If problem persists I'd change MAF and then throttle if it doesn't help, it won't be bad for any car this age anyway. Will definitely start with MAF as it is quick DIY job. Smaller errors from dying sensors, specifically those during warmup never get caught by ECU.

Can be fuel supply problems too...

[Sir WIll]

Interesting I have the same problem.

On my route to work in the morning the first few minutes the throttle just seems to be a little useless and not respond. You need to give it more of a push to get the car to go above a crawl.

Only thing I have on VAGCOM is one of the O2 sensors pre cat is playing up. Replaced it but still get the fault, though I do not think it's related.

A further note is that it feels when driving cold at a steady sixty or seventy that it's a little rough, almost like the road has suddenly been made of cobbles! All very strange but clears up when warmed.

[HPsauce]

Will use premium petrol first, like Shell Nitro. If problem persists I'd change MAF and then throttle if it doesn't help
Yes ;) have been running exclusively on Shell V-Power Nitro+ for some time I'll have a look at cleaning the MAF next.

Meanwhile I've been using Sport mode in the sort of situations when it occurs and "fingers crossed" it behaves. As that will be keeping the revs up would that change in behaviour be consistent with an "iffy" MAF sensor?

[notorious]

>> I'll have a look at cleaning the MAF next.

This usually doesn't help. I'm planning to change mine soon preventively just because it is 10 years old car.

When car is cold monitor MAF output with VCDS for erratic things...

[notorious]

And when you last time checked PCV valve?

It is tip top?

[HPsauce]

Never, but I've only had the car a few months and it's not something I know anything about or even where it is.
Is this thread a good starting point? http://forum.a8parts.co.uk/showthread.php?t=4826

[notorious]

Just google.

http://www.youtube.com/watch?v=2BmTyQsuW8U

http://www.youtube.com/watch?v=SzUjuXuip3E

http://www.getaboutauto.com/articles/TheBasicOperationOfAPCVVALVEPositiveCrankcaseVenti lation.html

[HPsauce]

And when you last time checked PCV valve?

It is tip top?

Well I've found it, but it's held in place by two, presumably original factory-fit, non-removable strong metal ties. :-(
These will need cutting off and replacing by reusable ones, so maybe another day if I can source ones of an appropriate size. (I don't think the plastic cable ties I have will be adequate. :rolleyes: )

[Delboy]

You sure it's not the clips that squeeze together over a tang, if it is you can get them off with nail pliers or similar. There is a proper tool for them too, think what your looking at is the clic r hose clips. Just Google clic r pliers and you will see what I'm on about

[HPsauce]

Thanks, could be; I'll go and have another look. Never heard of Clic-R before. :o

Another tool for the collection I guess. :ROFL:

Edit: Yes, looks like a Clic-R, but the one underneath will be a swine to get at!
(Heads off to eBay to look at tool options...)

[Dezzy]

The clips i've cut off or removed i've replced with jubilee clips

[HPsauce]

I've ordered some Clic-R pliers and will also get some jubilee clips next time I pass my local DIY place. :cool:

[Dezzy]

I've cut them off before using good wire snips, cut the locking part right off.

[HPsauce]

My Clic-R pliers arrived today and as the rain finally stopped I've been out to investigate the PCV valve.

Undid the clip for the side connection easily enough and eased the pipe off, then with wiggling and brute force with pliers managed to move the clip underneath round until it was accessible and undid that too.

Removed the PCV valve and finally, now I could access it, undid the idiotically-oriented jubilee clip fixing the short flexible tube underneath to the metal pipe below it.

Took the valve apart, which needs care and a bit of force - I used a large flat-bladed screwdriver to lever open the catches a tiny bit at a time, working round.
Took the diaphragm out carefully and checked it was in good condition.
It looked fine though a bit oily so I cleaned everything thoroughly with white spirit and isopropanol and reassembled carefully. I then checked (by sucking/blowing on the ports in turn while covering/uncovering the other one) that it was working OK and not leaking.

Put it all back on the car, ensuring that both Clic-R clips and the jubilee clip were oriented for easy access in future. ;). Ran car briefly to check it was OK.

Time will tell I guess whether the problem is still there. :rolleyes:

Footnote on the Clic-R pliers. The ones I bought were pretty cheap and didn't work that well (at first), especially for reclosing the clips.
Looking at videos online and pictures of seriously expensive ones I could see that the blades were poorly shaped. They had been initially forged or stamped then ground to shape inadequately. Quickly fixed with a metal file.

For reference, if anyone else gets these and has problems, the pliers are asymmetric; one side is a wedge, the other more like a chisel.
The problem with mine was that the "outer" face was rather rounded, from poor finishing, resulting in a thick working edge of varying thickness that prevented them making a good contact in the right place on the clip. I filed them down giving good flat working surfaces with narrow (but not sharp) edges where they press on the clips. The chisel edge in particular need to be quite thin to work properly.

[Delboy]

My Clic-R pliers arrived today and as the rain finally stopped I've been out to investigate the PCV valve.

Undid the clip for the side connection easily enough and eased the pipe off, then with wiggling and brute force with pliers managed to move the clip underneath round until it was accessible and undid that too.

Removed the PCV valve and finally, now I could access it, undid the idiotically-oriented jubilee clip fixing the short flexible tube underneath to the metal pipe below it.

Took the valve apart, which needs care and a bit of force - I used a large flat-bladed screwdriver to lever open the catches a tiny bit at a time, working round.
Took the diaphragm out carefully and checked it was in good condition.
It looked fine though a bit oily so I cleaned everything thoroughly with white spirit and isopropanol and reassembled carefully. I then checked (by sucking/blowing on the ports in turn while covering/uncovering the other one) that it was working OK and not leaking.

Put it all back on the car, ensuring that both Clic-R clips and the jubilee clip were oriented for easy access in future. ;). Ran car briefly to check it was OK.

Time will tell I guess whether the problem is still there. :rolleyes:

Footnote on the Clic-R pliers. The ones I bought were pretty cheap and didn't work that well (at first), especially for reclosing the clips.
Looking at videos online and pictures of seriously expensive ones I could see that the blades were poorly shaped. They had been initially forged or stamped then ground to shape inadequately. Quickly fixed with a metal file.

For reference, if anyone else gets these and has problems, the pliers are asymmetric; one side is a wedge, the other more like a chisel.
The problem with mine was that the "outer" face was rather rounded, from poor finishing, resulting in a thick working edge of varying thickness that prevented them making a good contact in the right place on the clip. I filed them down giving good flat working surfaces with narrow (but not sharp) edges where they press on the clips. The chisel edge in particular need to be quite thin to work properly.

Glad you got the somewhat correct tool for the job, were the clips easily put back on now that you modded your pliers?

[HPsauce]

Yes, they went back easily once the pliers were "flattened".
As delivered they had a bulge in the metal that lifted the blades away from the place where they needed to be. They have to make contact under the two locking components in order to force the two ends of the clip to overlap and latch together.
Mine were very like these but not so "sharp" until I filed them:

[HPsauce]

Time will tell I guess whether the problem is still there. :rolleyes:

Had to go out this evening; it behaved OK including a couple of "brisk" exits from side roads very soon after starting (within 200 yards) which normally show up the problem. Fingers crossed.

[Sir WIll]

Took mine out today, my little orange rubber seal it split.

Poor thing time for a new one. +++

[HPsauce]

Had to go out this evening; it behaved OK including a couple of "brisk" exits from side roads.
And on a fairly lengthy "day out" today with long and short runs and several long breaks, about 200 miles overall it's been fine.

Maybe my imagination but the throttle response seems "sharper" too. :cool:

But as noted earlier, only time will tell. And I put another £100 of Shell Nitro in this evening to make sure fuel is not the problem.

[HPsauce]

only time will tell.
Yesterday, with a number of short runs, I had a "hint" of misbehaviour on one occasion. :(

Today I've cleaned the MAF sensor and will "await developments".

On the basis of only ever changing one thing at a time (if at all possible) when diagnosing problems, what would people change first if problems continue - the PCV valve or the MAF sensor?
(neither job is difficult but the PCV is cheaper;))

[HPsauce]

Hmmm, definitely NOT cured. :(

Today, on my way out (to meet up with Adrian E & johnny_quattro) I had a definite lack of power turning left out of the bottom of my road onto the A-road (both 30mph limits). I had just "pootled" downhill gently to the junction from a cold start, maybe 300 metres at 25mph or so.
A quick "twitch" of the accelerator and it was back to normal and I joined the main road with some urgency! No further symptoms all day.

Just wondering if it could be in any way gearbox-related, i.e. sticking in a too-high gear as it slows down. :Confused:
Would flicking the lever across to tiptronic mode as I slow down at junctions enable me to see anything useful in the DIS if it was?

[notorious]

HP,

I'm going to change on my D2 2002 both MAF and PCV valve this winter.
I'll do MAF first and then PCV valve.
Same applies to lambdas and spark plugs.
I'll use genuine Audi parts.

I have no problems with performance and there are no errors.
It's just 10 years old car.

[HPsauce]

I ordered a new PCV valve from the USA in the end (cheaper) and it arrived on Saturday. Fitted this morning; now I know how (and have the right tool) that took under 10 minutes. :D

Just had a couple of short trips since, all OK so far. Fingers crossed again. ;)

[HPsauce]

all OK so far.
Sadly, it misbehaved a couple of times in recent days. :( No codes logged, so new MAF on order.

[HPsauce]

Well the MAF arrived, but it's not "New" as advertised. Box and item both labelled as remanufactured and looking at the state of the box, been kicking around for a while.:(

Is it worth fitting a remanufactured MAF? It's not a difficult job to swap - maybe 20 minutes max.

[PsYcHe]

Reman should be fine, it'll be a used case with new components inside usually. Warranty is usually the same as new.

[notorious]

Is it worth fitting a remanufactured MAF?

It depends where you purchased it. If it was purchased from Audi/TPS or directly from BOSCH i would fit it.

If it was private sale on eBay i'll return is asap hopefully seller accepts returns.

[HPsauce]

If it was private sale on eBay
Basically it was, looks like the seller probably buys up old stock from car parts shops (closedowns probably) and sells on eBay.
We're having sensible (formal, via eBay) communication about a partial refund so I might try it over the weekend and see if it works and is worth keeping. It does appear to be a genuine Bosch remanufactured part, not a cheap copy. Though I can't tell if it's been used as the packaging isn't sealed.

[notorious]

Dodgy. I'd return and purchase genuine Audi.

Don't look at casing and seals -- this is not important. The important is the sensor itself, which is a very small part in the middle of the 'pipe'.
The 1M$ question is whether the sensor was replaced with a new sensor and then calibrated in place.
If someone just sprayed a cleaner on the sensor this remanufacturing is not sustainable.

[HPsauce]

I'm fairly certain it is (or was) a proper remanufactured item, but not sure if it's straight from the factory or has been used. :tuttut:

Either way I now have it at an acceptable (to me) price for what it could be and will use it for testing/comparison if nothing else. It will help in my diagnosis as to whether this odd little problem is caused by the MAF sensor.

The engine does run OK with it fitted and there are no immediate/obvious problems on a couple of short runs. I'm not doing any long runs for a few days so the short journeys I do over the next few days should be a reasonable test, both of whether my problem is MAF-related and also whether this dubious one is performing OK.

Any suspicions or doubts and I'll be getting a brand new one from Audi. Meanwhile my old one is carefully wrapped up in the car, along with the tools needed to change it (just a large Phillips and large flat-blade screwdriver).

[HPsauce]

Sadly, the symptoms persist. :Confused:
I guess I'll be looking at the throttle position sensor next?

[notorious]

Have no more ideas about initial problem -- sorry.

I was reviewing PCV valve story as I'm going to change my PCV valve soon.

Opening ETKA revealed that two hose clips N 104 180 01 that require special tool where superceded with 'classic' hose clips with a bolt part number N 905 618 01 in cars with chassis number after F 4D-3-006 001. These are cars manufactured in August and September 2002, two months before D2s were removed from production -- 'final editions' perhaps.

Interestingly, rubber pipes and PCV valve itself where were left the same the moment they changed the hose clips, which proves that 'classic' hose clips will work just fine with older cars.

Although I have the special hose clip tool I'll be ordering classic N 905 618 01 hose clips with bolts as they are simply easier to work with.

[Sir WIll]

I have replaced the PCV Valve, MAF and fully serviced the car and still have the odd erratic throttle when cold.

Its either the sensor for it or the fact I have a fault code on one of the o2 sensors and that might be linked.

[HPsauce]

Sadly, the symptoms persist. :Confused:
I guess I'll be looking at the throttle position sensor next?
Or maybe not............

It still misbehaves occasionally and I started to think it was gearbox related - potentially VERY expensive.
There are some situations where it does if "fairly often" and it almost felt as if it was in the wrong (too high) gear, but the torque converter was possibly slipping. At other times it felt really "punchy". So I've started using Sport mode at "potentially iffy" times and so far it's behaving fine if I do, suggesting that the mechanicals are OK.

So, I'm beginning to wonder if the gearbox ECU is what's playing up and instructing the box badly?
Given all my water ingress issues I'm wondering some has found its way into the "box of tricks" under the bonnet with all the ECU's in. :( Not really the weather for taking the cover off and having a look at present. :tuttut: )

I recall that on my PF S8 I had a play with some of the gearbox ECU settings to make it more "driveable"; are there similar "tweaks" available for the later FL versions?
I think I mostly referred to this: http://www.audipages.com/Tech_Articles/auto_transmission/codingtransmission.html

[PsYcHe]

Have you checked the MAF?

[HPsauce]

Replaced it a while back, no change. ;)

[HPsauce]

I recall that on my PF S8 I had a play with some of the gearbox ECU settings to make it more "driveable"; are there similar "tweaks" available for the later FL versions?
I think I mostly referred to this: http://www.audipages.com/Tech_Articles/auto_transmission/codingtransmission.html
Finally I looked at this, prompted by digging out my laptop yesterday to (fail to) help Nollywood. :o
I recall this thread here as well, in which I posted: http://forum.a8parts.co.uk/showthread.php?t=6643 and I've been trying Sport mode a fair bit, which never gives problems.
There is also this generic thread with more details on what people have tried: http://forum.a8parts.co.uk/showthread.php?t=630

The current coding (which I'd never looked at) was 00101, just like my PF S8 had been initially, until I "improved" it with 00111.
So I changed it to 00111 and went for a little drive - can't go far, most minor roads around here are still flooded or blocked by trees and you need a bit of "give and take" driving to show the symptoms.

Anyway, so far so good, it behaved itself AND I could definitely notice it dropping a gear or two much more readily than before, yet not holding them as it does in Sport mode.

I'll report back when I've done a few more journeys, meanwhile has anyone else looked at and/or changed this coding on an FL D2 S8?

Edit: Just one thing I did notice, as part of my route was down a steepening hill in a 30mph limit, that I had good engine braking without taking any action on gears. :eek2:
Don't recall that before, certainly not on that stretch of road very near my house, so used regularly.

[HPsauce]

Interesting. Been a few more miles this evening and definitely feel a lot more confident pulling out briskly at T-junctions. +++
No sluggishness at all and so much confidence that I've given myself a couple of "energetic" surprises. :o

BUT I still (as I discussed with Nollywood on Sunday) prefer the throttle response on the PF. There's something about the fly-by-wire throttle and interaction between that and the gearbox that I'm not totally happy with. :tuttut:

[PsYcHe]

The PF did just seem so much more 'connected up'.. I still miss mine sometimes.

[HPsauce]

I'd definitely rather have one in good condition. +++ The extra 20HP doesn't really do anything useful.

[Sir WIll]

Rubs chin, that's very interesting.

I from time to time get throttle lag in normal mode but never had it in sport mode. I shall to do some more driving and investigation.

For reference mine is a 2002 FL with the sport mode on the box.

[HPsauce]

For reference mine is a 2002 FL with the sport mode on the box.Ditto. Have you scanned with VCDS and checked what coding is on the transmission ECU at present?

[HPsauce]

Oh dear, still being a bit odd..... :Confused:
This evening, having driven maybe 5 miles plus sat for 5 minutes with the engine running (so nicely warmed up) I drove a mile or so at 30/40mph then came down a fairly long and steep hill to an A road and turned left.

Good visibility, nothing coming, so I didn't come to a halt.

As I pulled away, not heavy on the throttle, the revs rose but without that much power so just gentle acceleration. Similar feeling to a "slipping clutch" in a manual.
I did the usual "quick lift" and it sorted of "kicked in" and off we went normally.

I'll be doing that bit of the journey again later this evening so will try and be a bit more observant.

Most of my oddities have, thinking about it, been on or about hills or steep junctions. Wonder if the gearbox fluid level isn't right?

[HPsauce]

Well, it's still misbehaving, but with no pattern that I can discern other than it's worse when cold. :(

I'm also still having occasional starting problems, it doesn't always "catch", or if it does "chugs" for a second or two at low revs before firing up to over 1000rpm on all cylinders and then settling down.

Any thoughts? I've gone back to V-power after a tankful of Esso 97RON a while back.

I think I'm going to swap the MAF back again when I get the chance as I still have the old one.

PS Nothing showing on a VCDS scan apart from the occasional 01119 - Gear Recognition Signal (Intermittent)

[HPsauce]

A bit more input on this, the starting problems are getting worse, though it's always OK when the engine is hot.
And the hesitation is still there at times, randomly unpredicatable as ever.
Today I asked a retired garage-owner friend of mine to observe a cold start after 2 days of non-use.

I just cranked it until it fired, which was a few seconds and very rough. After a few more seconds of idling it was running normally.
He was at the rear and said there was nothing unusual in the exhaust except a bit of unburnt fuel as expected.

Hi thoughts are maybe it just needs a new fuel filter, I have no record of it ever being done. 80,000 miles (nearly, service due soon!) and all Audi "long-life" servicing so far - would they ever change it?

Any other thoughts?

[notorious]

I change my fuel filter every two years. Do it myself. Buy filter and crusher gaskets and just change it. I can help you.

[ainarssems]

Fuel filter change is not in service schedule for petrol engines so it's probably have never been changed.

Is it maybe loosing fuel pressure, leaking air in fuel system when parked for prolonged periods of time. Or leaking injector slowly letting fuel in manifold which builds up while stationary and causes mixture to be too rich at startup until it vents out.

Or possibly one of temperature sensors is giving wrong readings.

[HPsauce]

Well as a first step I've just swapped the MAF back to the original and will see what difference, if any, that makes.

[HPsauce]

None. :(

[HPsauce]

Tried starting just now after sitting overnight unused.
Based on yesterdays experiences I pushed the throttle down a fair bit before starting.
It fired up quite quickly, but was very rough (definitely not all cylinders firing) and there was a strong smell of unburnt fuel. Settled down to normal after about 20-30 seconds of keeping the revs up around 1500-2000.

So possibly too much fuel or not enough air or both, but how to narrow down the cause? Or an ignition problem that goes away after a few seconds - maybe not?

While changing the MAF yesterday I had a good look round the air inlet, pipes, filter etc. up to the manifold and nothing appeared amiss. :Confused:

[Architex_mA8tey]

Are your manifold flaps operating correctly on startup?

[HPsauce]

I haven't checked them for a little while, but they certainly were OK last time I looked and all components appeared to be in top-notch condition, free to move and moving as they should.
A job for tomorrow I guess, but wouldn't they be in the low-rev position at the start, or does that require the bellows to move them - I can't recall which way round the actuation process works.
Could them being in the wrong position (whatever that is) cause this, if so how?

Edit: Just been having a read how this works.
Engine off the flaps are open, giving the shortest inlet (suitable only for high revs)
On starting the vacuum moves both actuators, closing both flaps and giving the longest inlet, suitable for low revs.
So if I had a vacuum leak there could, as they say, be "unexpected results" due to an inappropriate inlet manifold configuration.
I've read a fair few articles/postings about replacing the vacuum pipes with more robust ones.

[HPsauce]

Are your manifold flaps operating correctly on startup?Yes they are, I just popped out to check.
Took the engine cover off and moved them by hand, all seemed fine (though could they be broken inside?) with both bellows "relaxed".
Started the car, it just caught and "chugged" so I ran round to the front and both bellows had "sucked in" as expected and moved the arms.

Watched it for about a minute by which time it was ticking over smoothly.

[Architex_mA8tey]

Hmm ok well always good to check. I do think its worth changing the fuel filter as Ainars suggested to eliminate that possibility as they are not a huge cost. I've changed mine a couple of times since I owned the car. Sounds like the mixture is not right somewhere in the scheme of things so either fuel system or air breathers etc are main suspects Andrew

[HPsauce]

I also posted my latest symptoms over on AudiSRS as a fair few of them have similar engines. The first suggestion was the plugs giving up as it's due for a service.
With Audi long-life servicing up to now (80K about due when I'll do the cam belt, water pump etc. as well) how old could they be and could it be that simple?

[Adrian E]

May have only had 1 set of plugs in its life - think they're due at 40k? Defo worth changing but I wouldn't expect your symptoms to come and go if the plugs were the sole cause

[HPsauce]

Yes, it seemed like a long shot to be honest. Why would a significant proportion of 8 plugs start to misbehave at the same time?

Thinking about it maybe being excess fuel (for whatever reason) I tried a slightly different starting procedure just now; normally I turn the ignition on, open the mirrors and set the SatNav before starting the engine, so the fuel system gets pressurized:

Put the key in the ignition and immediately started it, keeping the starter motor going until I was confident it was running. No throttle.
It started badly but quickly though was still "chugging" somewhat around 500rpm after at most 3 or 4 seconds of starter motor when I released the key. But it quickly settled down nearer 1000rpm without me touching the throttle.
It was still a bit "rumbly" so I revved it for a few more seconds and it was then idling smoothly.

[HPsauce]

I'm just wondering how much of a factor fuel could be, presumably in conjunction with something else?
My last 2 fill-ups have been (I think) Esso 97 followed by BP 97. Neither of which I have ever used before in this car.

Today, getting a bit low and needing to go out I called in at my "local" and filled up with cooking 95 (Esso). Only took 55 litres as I got the "tilted down filler" side of a very busy (bloody Tesco local shop and people "park" at the pump! :angry2: ) forecourt so will be a bit of a mixture. Did about 10 miles so the fuel lines should be well flushed through.

The "theory" is that lower octane is easier to ignite, I'll see how it goes over the next few days.
When I got home it was nicely warmed up and starting fine, as ever when hot.

[Kalchev]

80k miles with a single fuel filter? Wow you really got clean fuels :D
Get a good quality fuel filter and change it asap - it's cheap compared to all you have done and the change is real easy. If it's not the filter, it's value added for the operation of your audi. 80k miles with one filter... wow. Not sure what kind of marketing the audi long-life servicing is. I change filters every 10-15k km, including the petrol filter, disregarding the fact I'm on LPG. I use only VW spec or better filters, you just can't compromise with these, they are consumable anyway.

[HPsauce]

No difference with 95 RON.
Fuel filter will be replaced when it's serviced in about 10 days time.

But..... FINALLY I have a sort of error code:
16500 - Engine Coolant Temp. Sensor (G62): Implausible Signal
P0116 - 35-10 - - - Intermittent

Could that cause these problems?

The sensor is about 9 months old, so I'm trying to get a warranty replacement as it was supposedly guaranteed for 2 years. :rolleyes:

[HPsauce]

This morning I put the old sensor back (yes I kept it!) and it started fine and felt suitably brisk and urgent on the road.
Been for a bit of a run and it started OK again when I got home; will try again in an hour or so.

The problem with the old sensor is that the temperature display on the dash was always low, but the unit has 4 pins, so is there a separate sensor in it for ECU use?

Might toddle off to ECP on Monday and get a proper new one. Though fitting them is a bit of a pig. :(
Every step is easy and quick, EXCEPT fitting the locking clip back in, which with my big hands took longer than the whole of the rest of the job combined, and then some!
It's easy to lose as well, so "TIP" I tied a long bit of thin string around it so it didn't disappear down behind the engine.

[HPsauce]

The problem with the old sensor is that the temperature display on the dash was always low
But it's now also throwing a solid error code that comes back immediately on clearing:
1 Fault Found: 16502 - Engine Coolant Temp. Sensor (G62): Signal too High P0118 - 35-00 - - Readiness: 0110 1101

So I'll get that replaced ASAP. Anyone know the significance of the Readiness code, it was 0000 0000 yesterday but the engine was running today while scanning?

As for the sensor I took out, only a few months old, but giving this:16500 - Engine Coolant Temp. Sensor (G62): Implausible Signal The thing actually rattles if you shake it! Obviously something has broken inside. :angry2:

[nakata]

If not have other error at ECU. Erathic throtel response is from fuel injector. I have the same problem, with the change of them is normalize it. First sympthoms is at cold engine and going worst at the time. Is good to change and presure regulator which is responsibile for not starting at first time at cold engine.

[HPsauce]

I'm going to see how it behaves with a proper coolant sensor first. ;)

Checking back on my VCDS scans it had an intermittent problem with that sensor from before I bought the car.
That problem got worse and I replaced it with what turned out to be a cheap piece of eBay rubbish that failed badly relatively quickly.

Today I bought a proper OEM part (£40 vs £7.50 on eBay) and will fit it later. :cool:

[Bandycoot]

I've been getting the very same problems on my FL S8. Just to add a bit more confusion into the mix; have you checked for air leaks. Since my problems started I have found a few air leaks in the induction system and have replaced the two rubber elbows on the air box and throttle body and now I feel I have air leaks in the manifold.

Like you I've changed my MAF and a few other things without any result.

One thing you can do which may help is to give your throttle body a good clean with some carb cleaner. Refit with a new gasket and see what happens. You may have to do a throttle body adaption afterwards but this is a simple process.

My problem doesn't happen that often now as I think I'm getting close to solving this once and for all but a trick I use when it does occur is this: stop the engine then turn the ignition back on without starting the engine and leave it for at least 30 seconds before turning the ignition off. Turn the ignition back on and start the car. During this process DO NOT TOUCH THE THROTTLE PEDAL or else it won't work. If this procedure works for you then it could indicate a problem with the throttle body.

Hope this helps.

Steve

[HPsauce]

Thanks for those observations, and yes I'm still getting it at times.

The thing is it goes away immediately if I blip the throttle, so no need to do that procedure. And I have done the TBA process (using VCDS) a while back, it all went smoothly and nothing really changed. :Confused:

Is it possible to access the throttle body directly on the car and give it a bit of carb cleaner squirting there? I'm not really quite sure where it is.
The air pipes I'm pretty sure are fine.

[HPsauce]

Well it happened again today, when the car was totally warmed up near the end of an 80-mile run. :Confused:
I was leaving the M25 after several miles at "motorway" speeds, down a reasonably long slip road, so braking gently for maybe 200 metres to a roundabout under the motorway.
At the bottom I had to come to a complete stop as there was traffic (one small car!) on the roundabout, I then entered the roundabout and took the next exit, following it.

As I moved off I could tell it was misbehaving again, but it's a very quiet junction with nothing behind me or even in sight apart from the car I'd waited for, so I just lets things develop.

It moved off quite gently, even though my foot was down a reasonable amount, revving up to maybe 3500 before changing up a gear then carried on the same. It was a bit like driving a manual car with a slipping clutch. It was in full auto mode so I don't know what gears it used.

After the gear change I got bored and "blipped" the throttle, reverting everything to standard behaviour and overtook the little car (empty dual carriageway with 70 limit).

Does this give any clues anyone can interpret.

Fuel today was Sainsburys "Super" (97?) as we had a 10p off per litre voucher to use!

[HPsauce]

Today I replaced the Fuel Pressure Regulator, as discussed in this thread: http://forum.a8parts.co.uk/showthread.php?t=8351
I did buy a "cheap" Meat & Doria one (MD75013) but am prepared to get the OEM Audi one in due course if that is unsatisfactory.

Although I did release the pressure by undoing the 17mm nut on the fuel feed pipe it wasn't actually pressurised, though the car had been unused for nearly 2 days and it was in the cool of the early morning.
Getting the old FPR out was a bit of a struggle, it was very tight. Mole wrench to the rescue, with lots of wiggling and rotating. The new one went in fairly easily with just a firm push and a twist.

Turned the ignition on and could briefly hear the fuel pump refilling the unit until it stopped. No leaks evident so started the car and it was fine.
Went for a short drive and all seemed OK and suitably brisk, but the symptoms are intermittent so only time will tell.

[Architex_mA8tey]

I did buy a "cheap" Meat & Doria one (MD75013)

is that Meat & 2 VAG? :D

[HPsauce]

Hmmmm, well it's a bit different, but I've only done a handful of short runs (1 to 3 miles).

Once moving it seems as normal, but:
Starting is different, less "instant" and in one case (when warm) took a few seconds to catch. What are other people's D2's like to start?
I've noticed one possible brief "higher revs but sluggish progress" event after pulling out at a T-junction when the car was warmish from earlier use but had only been driven about 200 yards that time.

Starting, after I changed the coolant temperature sensor, was always quick and "violent" with a short burst of high revs (over 1500rpm) before quickly setlling down to idle.
Now it takes a bit longer but just goes straight to normal idle speed after a tiny initial blip at maybe 1000rpm.
Maybe fuel pressure was too high before and isn't high enough now? But "on the road" it's as responsive as ever - I had a little "play" this morning to check. :tuttut:

[steamship]

Have been reading this thread and noticed that no one else seemed to experience a similar problem. Since the meet in June, I've been focusing more on trying to sort out my garden and have been not paying attention to the car. I was out the other day, and experienced the exact same symptoms. I live down a very rough lane so I tend to crawl up it anyway. When I went to move onto the road, there was lots of revs but very little movement. It was almost as if you were driving with the handbrake on. It was only a short 4-5 mile run, but I noticed the same sluggishness several times, usually around junctions. I know I still have issues with SAI and fuel mixtures, but the one thing I did discover was that I was low on oil. Very low in fact, as it was just below the minimum mark (told you I hadn't been paying attention to the car). Anyway, I topped it up and the following day when I was out on another short run, it was as responsive as ever. Don't know if this is significant or not, but as you've experienced this on a number of occasions, it if was solely a low oil issue, I'm sure you would have spotted it before now. Mine is also LPG, so it doesn't appear to be fuel/petrol related.

[HPsauce]

When I went to move onto the road, there was lots of revs but very little movement. It was almost as if you were driving with the handbrake on. It was only a short 4-5 mile run, but I noticed the same sluggishness several times, usually around junctions. That does sound similar, though I can't see how engine oil level would have that effect. :Confused:
I've recently had a full major service (cam belt, water pump, the WORKS) so would be very surprised if the oil level was wrong. No warnings, though I haven't checked it lately.

[HPsauce]

I'm still confused by this, it's certainly a bit different since I changed the FPR. I was going to swap it back but have had problems with the other car (Focus - fuel pump fuse blew!) so I'm not touching the Audi at present as I am relying on it.

I now seem to have 3 modes of operation:
1. Normal (most of the time)
2. Sluggish, rare as reported above, resolved by a quick "blip" of the throttle
3. Scalded cat! :Confused:

The latter is new. Just using middling throttle (definitely not flooring it) it will sometimes take off much faster than I'm expecting. And you can really feel the power kick in as the flaps open at higher revs.

Forgot to add, starting is still a bit "iffy"; I find that if it doesn't catch quickly I turn off and try again and it's usually OK 2nd (or 3rd) time.

[HPsauce]

Finally decided to swap the Fuel Pressure Regulator back as I still keep getting little glitches at inconvenient times.
Just been for a little drive round in road conditions that often trigger it and all seems OK so far. At least I didn't break the old one getting it out with a mole wrench. :o

This time I used a little rubber-surfaced gadget we have for getting the tops off jars, that is much more gentle and enabled it to be wiggled out very quickly.

There's a good discount at ECP at the moment so if I want a genuine Bosch one they're only about £60.

[HPsauce]

Well, I've done quite a few short journeys today and all was going well, even at places that "often" show symptoms. The car was really quite "sprightly".

Then I did the short journey that is almost guaranteed to give problems and.....It was almost as if you were driving with the handbrake on. :(

To explain, I leave my house (which is on a corner of a side road so there's a bit of reversing and wiggling initially) and drive "down" my road to its end, some 350 yards downhill in a 30mph area steep enough to require minimal throttle or braking until stopping at the end where it joins a main road.
I then stop and turn right (mostly) onto a single-carriageway "A" road (still 30mph) and very often get these symptoms. It's slightly uphill and a fairly busy road so you need "reasonable" throttle, though this evening the road was empty so I didn't rush.
I drove about 200 yards with the engine revving around 3000rpm at under 30mph (and at least one gear change) before I got bored and "blipped" (released and repressed) the throttle at which point it reverted to sensible behaviour, pulling well around 1500/2000rpm.

Subsequent journeys this evening have been through very similar junctions (it's a hilly area) without problems. :Confused:

[steamship]

Bummer! I was hoping you'd finally sorted this, since I experienced something similar recently. I haven't had the 'scalded cat' effect yet, but then I still have issues with SAI and fuel mixtures running on LPG.

Your description of your drive to the main road was very interesting as it sounds similar to mine, the only difference being mine is about 3/10 mile long and involves avoiding potholes in the lane.

[Delboy]

I can't help but think these issues are gearbox related , have you tried leaving the house in tip mode and tried different gears like first all the way to the junction 2nd all the way etc etc

[HPsauce]

Delboy, I've had similar thoughts and tried Tip mode, though not consistently (I keep forgetting :o ) so it's not proved anything yet.

None of this is reproducible, it's intermittent - despite what I said about the "almost guaranteed" route which is one (due to traffic conditions) that I would only do at most once a week. Normally I go a different (only 50 yards longer) way to avoid a right turn onto a busy A road, whichever car I'm in.
I'm a creature of habit on which route I choose so don't think about it.

I can go that way later this morning, so I'll try and do it "Tip only", assuming I remember.

[HPsauce]

OK, so here's some relatively good diagnostic info. Today I have made 4 short journeys, all about a mile long and all in Tip mode.

1. About 9am with a cold engine, including my "dodgy right turn", seemed fine.
2. About 11:30am, with some residual heat from 9am, seemed OK.
3. Midday, engine still warm, thought I felt a couple of "twitches", decided to go out again 5 minutes later.
4. Just now (12:10) with a warm engine I had definite problems as described below.

Headed downhill from my house, tipped up to 3rd then 4th gear and stopped at main road very briefly, it dropped to 1.
Saw a good gap in the traffic and headed off, turning right it was definitely showing 1. VERY sluggish (for an S8)!:(
Changed up to 2nd, still sluggish but eventually got to approaching 30mph and around 3000 revs (does that compute?).
Blipped the throttle (release, press) and it instantly felt responsive, revs unchanged but started to increase revs/speed with normal power.
Changed up to 3rd and 4th all normal, then slowed for a roundabout which it pottered round in 3rd; cruised around the block normally at 30mph in 3rd/4th and went home to write this.

Thoughts welcome. :Confused:

PS. I guess the thread title may be a bit off the mark as well.

[Nuisanceneighbour]

Just out of interest, what happens if you continue to press the accelerator during the sluggish periods? Contrary to what I posted the other day I am still experiencing symptoms of a very similar nature to what you describe but on the 32v engine.

On occasions of sluggishness I have depressed the accelerator in frustration which results in the CAT warning light illuminating and a huge loss of power twinned with a jarring thud to the transmission. Less than a second later the warning light has disappeared and power delivery is restored albeit in the same sluggish form as moments earlier.

I have noticed at times of poor performance the car seems to change up the gears prematurely (25-30mph on a hill the car will select 4th gear).

[HPsauce]

Just out of interest, what happens if you continue to press the accelerator during the sluggish periods? In Auto mode it just changes up gears and accelerates gently until I get bored and "blip" the throttle.
It doesn't normally happen in a situation where I have the luxury of waiting to see what transpires.

I've ordered a genuine Bosch Fuel Pressure Regulator (from ECP) in desperation, should arrive tomorrow.

[Goran]

I'm still confused by this, it's certainly a bit different since I changed the FPR. I was going to swap it back but have had problems with the other car (Focus - fuel pump fuse blew!) so I'm not touching the Audi at present as I am relying on it.

I now seem to have 3 modes of operation:
1. Normal (most of the time)
2. Sluggish, rare as reported above, resolved by a quick "blip" of the throttle
3. Scalded cat! :Confused:

The latter is new. Just using middling throttle (definitely not flooring it) it will sometimes take off much faster than I'm expecting. And you can really feel the power kick in as the flaps open at higher revs.

Forgot to add, starting is still a bit "iffy"; I find that if it doesn't catch quickly I turn off and try again and it's usually OK 2nd (or 3rd) time.

All I can add is that this reminds me exactly how my old S8 behaved. Sometimes normal, sometimes sluggish, and on rare occasion accelerates faster than expected without much throttle.

My guess is its the Transmission software which can limit engine torque that's causing these varied behaviours. Certainly no such behaviour on the manual S8, doesn't matter if the weather is cold, warm, engine cold or warm, it just pulls the same with only the standard split-second delay every time (probably because of the electronic throttle). More like a jerk really rather than delay and could be because of the manual running gear, clutch, flywheel, etc.
So by deduction if you eliminate the transmission and these symptoms dissapear, the Auto symptoms must be transmission related in a lot of cases?

[HPsauce]

So by deduction if you eliminate the transmission and these symptoms dissapear, the Auto symptoms must be transmission related in a lot of cases?Any suggestions how to do that? I've tried in Tip mode and the symptoms were still there as noted a couple of posts previously. :(

[HPsauce]

I've ordered a genuine Bosch Fuel Pressure Regulator (from ECP) Arrived and fitted. Slight oops in that I forgot to tighten up the connection to the fuel rail that I'd loosened to release the pressure. :o Very smelly of V-power around the engine bay for a while until it evaporated. :tuttut:

Been for a drive round, lots of short segments, stopping and starting in between and choosing "challenging" junctions. All in Auto mode. No problems so far.

[Goran]

Any suggestions how to do that? I've tried in Tip mode and the symptoms were still there as noted a couple of posts previously. :(

I meant, if we assume both my S8ts were healthy engine wise, and I swapped from the Auto version to the Manual, and the hesitation/scalded cat disappeared, the Auto transmission must? have been causing the effect.
I know its a crude deduction, considering so many factors between the two cars. I just cant shake the thought that because there is a TCU module and software in the Auto ECU to reduce engine power for the benefit of the transmission, its bound to be trouble. As far as I know the manual version has no such interference (different software, no TCU), so the engine will respond directly (with proviso that its electronic) to pedal input, and doesn't care if you burn the hell out of the clutch. I know I have already done so on a couple of occasions :)

You cant remove the TCU and ECU software for TCU interference and still drive the car, so its not testable on a Auto version. I assume in the Auto TCU interference is always available even in Tip mode, to protect the transmission. Maybe if Mike does his manual conversion he will be in a unique position to test what happens when you swap transmission types (and remove TCU) without changing the engine.

[HPsauce]

I like your thinking Goran. It certainly feels to me (as a computer guy) more like a control electronics issue than anything else.
The puzzle is mainly what conditions trigger it, it's not consistent enough yet to start pointing the finger in any specific direction, though significant turns at lower speeds seem to be implicated.

[Delboy]

I know from my D3 that the gearbox ecu asks for a gear change and there is sometimes a hesitation in the gear change compared to whats displayed on the dis.

The 3000 rpm but little acceleration can only be gearbox related with either a clutch pack slipping or the torque converter slipping with the gearbox being in to high a ratio.

I'm unfamiliar with D2's so not sure if the box behaves the same as the d3 but in the d3 in sport mode the tcu locks the torque converter up earlier to allow for a more direct drive allowing for better acceleration.

Have you got sport mode on the D2?

[HPsauce]

Have you got sport mode on the D2?Yes, and I've also been told it locks up in Tip mode, but I get the same problem there.

It doesn't really feel like anything is slipping, just lack of power from the engine and reluctance to change gear (up). When I "blipped" the throttle in Tip mode it didn't change revs or gear but suddenly felt urgent and responsive.

[HPsauce]

I don't know if Jesse (Fast Show :snigger: ) ever had a whole week of HP sauce, but....
Today I 'ave mostly been driving........... an S8! :yippee:

I'm not saying it's fixed, only time will tell for sure, but it's consistent and responsive, getting a "decent move on" with only a gentle right foot. Without any need to use Sport mode, but if you do it really does get going. :cool:

This makes me think that what I referred to previously as the occasional "scalded cat" mode was in fact just "normal S8" and that my right foot had learned to be heavy from being used to it being pretty sluggish most of the time unless I floored it.

Certainly feeling more positive today. +++

[David's8]

Good news and I hope - for your sake - that what is possibly the longest running thread on a single problem will come to an end. +++

[HPsauce]

I hadn't realised how long it was! I wonder if the previous owner (and the trader I got it from) knew it had this weird problem and hoped it wouldn't show up too much. :tuttut:

Anyway, it's also starting better, so now I just have to wait and see how it behaves.

[Sir WIll]

Interesting stuff my D3 does have similar problems so I may change the Fuel Pressure Regulator and have a look.

Anyone have the part number for a 2003 D3 4.2v8?

[HPsauce]

It will almost certainly be the same, but put your car details in on the ECP web site to confirm.

The Bosch one I got was ECP part number 440440090 which according to them applies up to 05/2006.

Note that I now have a spare briefly-used aftermarket one (noted earlier in the thread, cost me £34) that I just don't know for sure is good or bad.
Happy to pass it on at a big discount (P&P plus beer money I guess) if anyone wants it for testing.

[HPsauce]

wait and see how it behaves.Still feeling good. :D
Picked SWMBO up just now from the station (3 miles away) and on the way back decided to try Sport mode. She was not best pleased. :ROFL:

[steamship]

Note that I now have a spare briefly-used aftermarket one (noted earlier in the thread, cost me £34) that I just don't know for sure is good or bad.
Happy to pass it on at a big discount (P&P plus beer money I guess) if anyone wants it for testing.

Keep us updated over the next few days, and if the car is running well and you still have the other one, I'd be interested.

[HPsauce]

It's available now if you're interested as I still have the original factory-fit one as backup. :cool:

The one thing I can say is that I've seen different behaviour (slightly, but I'm convinced) between the 3 (original, aftermarket and latest Bosch) though the Bosch one has only been in for under 2 days.

It's probably not going anywhere now until Monday.

[Norretal]

Still feeling good. :D
Picked SWMBO up just now from the station (3 miles away) and on the way back decided to try Sport mode. She was not best pleased. :ROFL:

It's a lovely feeling when an ongoing problem seems to have finally been sorted, your persistence looks to have paid off, congratulations +++

[HPsauce]

your persistence looks to have paid offThanks, but I'm taking nothing for granted as yet. It definitely feels better but I could be deluding myself or just be down to a change in the weather.

On an unrelated negative note, this evening my RNS-D decided my map CD (supplied by Adrian E and discussed at length elsewhere) wasn't valid, though it did eventually work after several ejects/inserts. Odd as neither car or weather were hot (usual factor in unreliability) and it's been fine for quite a while now even on the hottest days.
Though I guess there will be a new map release soon?

[HPsauce]

Been for a bit of a potter today and all seems well. Fingers and legs crossed.

Observing the revs/gears very carefully the change points don't seem much different to when it was in "slugged" mode, so I think the gearbox behaviour is consistent, just a huge loss of engine power.

I'll plug in VCDS shortly but don't expect to see anything of interest except the ever-recurring, intermittent and elusive ABS code "01119 - Gear Recognition Signal".
Edit. Forgot the alarm horn, low internal voltage - another job already on the list. Otherwise clean as a whistle! :D

[HPsauce]

Today I've done a fair few miles (200?) over lots of short journeys and a couple of longer ones. (and made two visits to my favourite V-Power emporium! :ROFL: )
No embarrassing "lack of power when pulling out" sessions I'm glad to say. And generally the car feels very sprightly, my right foot has been much lighter than recently but with better effect. :D

Had a couple of odd moments, but they were just moments and when I was doing out-of-the-ordinary things. I think they were the typical "confused ECU" events that I've experienced on many automatic cars where with sudden changes of turning, braking and accelerating the electronics can't quite decide what you're actually trying to do and change into the wrong gear at the wrong time then change again quite quickly to what you really need.

As an aside I wasn't 100% sure on my kickdown switch, so I checked it's "click" and decided clockwise was "on", then tested it as I joined the M25. Straight past 6000rpm in a flash! :tuttut:

[HPsauce]

I'll plug in VCDS shortly but don't expect to see anything of interest except the ever-recurring, intermittent and elusive ABS code "01119 - Gear Recognition Signal".
Shock, horror! :eek:

I plugged in VCDS after fixing the alarm horn with new batteries, cleared the errors related to that and did a full scan.

What did I find to my total amazement? I've never, ever seen this before.
Nothing. Zilch. Nada. Sod all. No error codes whatsoever! A totally clean scan. :rockin:

Even the 01119 has gone. Could the new Fuel Pressure Regulator have cured that? Or (worse) something else cured the 01119 which was in turn causing the throttle oddness. :Confused:

[ainarssems]

More likely this:

Or (worse) something else cured the 01119 which was in turn causing the throttle oddness.

Fault and incorrect signalling could cause torque reduction request being sent from ABS to ECU, hence varying throttle response. Possibly dirty ABS sensor or ring.

[The_Laird]

A totally clean scan. :rockin:



Delighted for you! :mexicanwave:

[Architex_mA8tey]

I think you should celebrate by coming to audis in the park . . . I promise I wont touch your rear headrests!!! :D

[HPsauce]

. . . I promise I wont touch your rear headrests!!! :D

I'll come if you promise to fix them (it, the other is OK) ........

[HPsauce]

:angry2:
Yes, it's misbehaved again. Big time. But only once in a number of short journeys. :Confused:

Left my house this evening (car unused for almost 24 hours) and drove up my road (200yards) then did a sharp left uphill at a T-junction and a sharp right also initially uphill at another T-junction just a few yards on into a B-road.

Low power! I went from 1st to 2nd to 3rd very gradually at highish revs (3000+), reaching about 40 mph, before I intervened. After that the car behaved perfectly on a 3-mile journey, as it did on the return an hour or so later.
I plugged in the laptop and ran VCDS - nothing recorded at all. Clean :Confused:

Went out a bit later, two short journeys about an hour apart again, all fine.
Came back and scanned again with VCDS - an 01119 showing this time in ABS.

[HPsauce]

A couple of journeys this morning very similar routes to last nights; no problems and no codes either - not that that seems to prove anything.

I'll be carrying my laptop with VCDS around with me from now on and plugging it in ASAP after any "glitches".

Edit: A few more short journeys today and no dramas. No codes either.

[David's8]

I know that this is a bit off the wall but these episodes always seem to happen on bendy bits and junctions? Are you not accidently hitting the tiptronic buttons on the wheel as you are turning the wheel which then drops the gear so you are revving without going anywhere. I know that I have done the same on a few occasions and thought that "something was wrong" when in fact it was a finger problem. The car seems to think that you are demanding high revs at low speed and therefore keeps the game going.

[HPsauce]

Definitely not.

[David's8]

Definitely not.

Didnt mean to insult you there but without having direct experience of the symptoms its hard to understand the problem fully. I guess the issue is not so much one of a lack of velocity but a definite lack of power at the actual revs?

[HPsauce]

without having direct experience of the symptoms its hard to understand the problem fullyEven with now almost 18 months of DIRECT experience of the symptoms I am nowhere near understanding the problem!:angry2:

[steamship]

Even with now almost 18 months of DIRECT experience of the symptoms I am nowhere near understanding the problem!:angry2:

Sorry to hear that this is still ongoing. I've only experienced it a few times on a shortish trip last month, so at least know the symptoms.

[HPsauce]

Didnt mean to insult you You didn't, I'm open to any and all ideas. :cool:
Today I "think" it was all OK, going to AITP and back, and no codes whatsoever showing at the end of the journey(s).
Roads coming home were not bad, so several "overtaking opportunities" were enjoyed, a couple making full use of kickdown.

And yes David, it's a BLATANT lack of power (which will continue, given enough time and no-one behind you, up through at least two automatic gear changes), which returns instantly if you release the throttle and press it down again to the same extent. :Confused:

[HPsauce]

Today it was driven some distance by a friend of mine (in the motor trade, the guy who helped me buy it) and he said it was perfect.

Also passed it's MOT (he took it there as a favour) with 2 minor advisories:
1. One of the four rear light bulbs had blown (sod's law, it was fine yesterday when I checked)
2. Slight deterioration of a NSF inner suspension bush, but no excessive movement.

Also no codes whatsoever showing when scanned later.

[B@fink]

Enormously unlikely but since you have eliminated all the ignition/injection issues and you aren't getting fault codes and as it seems to occur on random corners/slopes have you considered the possibliity that there's a physical issue that's the cause? If some of the baffle stuffing or one of the catalysts are moving/loose it could act as a partial blockage cutting the power dramatically and as you turn/accelerate/release the throttle (or whatever restores the performance) it could then return to the correct position and it drives normally again. It isn't likely but not an impossibility and you might not have thought of it? Trying to think outside the box here ;) I did have a car whose baffle stuffing started to come out that was intermittent on power before loosing it's go altogether which resolved my confusion to the power issues as the exhaust pipe had gained a dangly tail of stuffing out of it! new back box and it was back to normal. Hope all ideas are welcome.....even the slightly left field ones :D

[HPsauce]

Left field ideas welcome. +++
One of the cats was rattling when I bought the car, probably still is. Passed 2 MOT's since though.

[B@fink]

Perhaps It could still function correctly (I.e. Pass the emissions test) when not in the shifted (and blocking the exhaust) position, as long as the gas can get through the catalyst to react it will convert the gases still? Not sure how you could check it but stranger things have happened :)

[HPsauce]

I know it's only a few days, but the last time I experienced any oddness (low power, high revs at medium throttle) was about a week ago when I turned right at a T-junction on the A595 in Cumbria where it is joined by the A5093 at the coast near Silecroft.

After that I proceeded straight to the Hardknott pass which gave the gearbox a "good seeing to" on both 1 in 3 up and down slopes. During and since that journey it's felt fine. http://forum.a8parts.co.uk/showthread.php?t=8864

I wonder if there was some "redistribution" of fluid (or air bubbles or sludge?) as a result........:Confused:

[Reffro]

Just a quick observation, your power issue seem recently to be joined with sharp turns. Is there something amiss with your power steering pump? I remember when on full lock in my old D2 it used to cause the revs to dip slightly.

Also with regards to rattling cats, that was definitely a cause of power drops in my car, at times it felt like it I had thrown out the anchor, as the material in one cat used to move and block my exhaust flow.

[ainarssems]

Could it be ESP sending torque reduction request to ECU as this seems to happen on hills and turns maybe roll, yaw or acceleration sensors inside ESP unit are not reading quite right always. poor connection, dry solder joint maybe.

[HPsauce]

Yes, it's definitely associated with sharper turns, though not hard ones as it's usually at low speeds so minimal lateral forces.

I think the acceleration and yaw sensors are under the drivers seat so maybe I'll try to find and re-plug those. The yaw sensor sounds more relevant.

But the condition 100% clears with a twitch of the throttle (lift off and reapply) so I'm dubious, unless that somehow makes the relevant ECU have a rethink? :Confused:

If it was readily reproducible I could try with ESP off and see if that changed things, but it's not predictable enough.

[PsYcHe]

Maybe the steering angle sensor as well, giving incorrect readings, so causing the car to think that there's a slide on..

Do you get the ESP light flashing when it does it? That would maybe point it more to the cat/PS pump if not.

[HPsauce]

Definitely NEVER seen any ESP light when this happens.

[HPsauce]

the last time I experienced any oddness (low power, high revs at medium throttle) was about a week ago ...........
After that I proceeded straight to the Hardknott pass which gave the gearbox a "good seeing to" on both 1 in 3 up and down slopes. During and since that journey it's felt fine.And is still fine after nearly 3 weeks. :Confused:

[HPsauce]

Just a minor update on this still-unresolved issue.
Errant behaviour still happens every now and then, so I've now followed the lead of some others and order a replacement throttle pedal position sensor (potentiometer) from our sponsors.

The car is due in for a check up on a lift later this week; loud rattling when cold from under the car (stationary or moving) so I suspect that the iffy catalyst is on the way out and that the SAI pump is adding to the symptoms when cold. Might get the garage to fit the replacement potentiometer at the same time if it has arrived.

[RanjS8]

Have u consider the fuel pump relay or fuel pump?

[HPsauce]

Hi Ranj, yes I've considered it (and had the filter replaced) but the FACT that it ALWAYS reverts to normal good behaviour with a little off/on twitch of the throttle pedal suggests the problem is elsewhere.

[steamship]

Have u consider the fuel pump relay or fuel pump?

Mine sort of confirms what HP says, as I have a similar problem, but not as pronounced, as mine runs on LPG, and the twitch on the throttle resolves it.

[HPsauce]

I suspect that the iffy catalyst is on the way out Definitely is, extremely rattly. But over £1000 to replace with a new one. :-(

[HPsauce]

OK, so here's a really INTERESTING bit of diagnostic data.......

The catalyst was replaced yesterday and not long after I "thought" I detected a hint of the problem, but in a few short journeys since it's been OK.

Then an hour or so ago I had the opportunity to take a non-optimum route somewhere but one that often creates the symptoms. And it did! So, not the catalyst as a cause. :tuttut:

Now, it always behaves fine on cruise control, so I had wondered - what happens if I switch cruise on while it's having a "go-slow".

The symptoms appeared as I turned slowly into a main road with a 30mph limit, so I let the car accelerate gently (throttle pedal pressed some way down to do that) then hit the "set" button at 30mph without moving my right foot. I don't recall exactly but it was probably near 3000rpm when I did that - would that be 2nd gear?.
Wallop! :eek2: It instantly set off like the proverbial scalded act! :eek3:
Took my foot off and it eventually slowed and settled back down to 30mph on cruise.

So, what does that tell us? :Confused:
I don't think it took the time to do anything in the gearbox, the response was literally instant, going from gentle to heavy throttle, as if it had reread or reinterpreted the pedal position.

Any and all thoughts welcome......

I'll try it again whenever it happens and it's safe to do so. Anything worth noting at the time or changing?
(one thing I might try next time is pressing the cruise set button at a lower speed, below the normal activation limit which I think is 25mph.)

[Delboy]

Almost sounds like it's not reading the throttle pedal position correctly, cruise control makes its own calcs and therefore commands the throttle wax accordingly.

Did you ever check the wiring to the pedal sensor?

[HPsauce]

The intriguing thing is that it appears that the throttle pedal is being misread/under-read OR misinterpreted BUT just pressing the cruise set switch means that the pedal is read correctly (maybe it's reread?) and as it's already a fair way down it overrides the cruise setting until I lift my foot when it settles down.

It makes me think there's something weird going on in the engine ECU.

[brasiliangringo]

Just a minor update on this still-unresolved issue.
Errant behaviour still happens every now and then, so I've now followed the lead of some others and order a replacement throttle pedal position sensor (potentiometer) from our sponsors.

The car is due in for a check up on a lift later this week; loud rattling when cold from under the car (stationary or moving) so I suspect that the iffy catalyst is on the way out and that the SAI pump is adding to the symptoms when cold. Might get the garage to fit the replacement potentiometer at the same time if it has arrived.\

If you post up your short / long term fuel trims at idle i can advise if they are healthy, group 033 ad 034 screen grab.

Make sure you have some miles on the car since the last time you cleared codes in engine module group as is reset when this happens.

[Delboy]

Of course I mis read that, so it's possibly re reading the demand then noticing a different value then taking off.

How about as a test start out each journey and get the cruise control set at say 50mph and leave it active but not engaged, then if the car bogs down, don't throttle anymore but instead hit resume and see if the car starts to accelerate normally again.

[HPsauce]

Tricky to do that as it only normally bogs down near the start of a journey and at a low speed when moving off. And I'm sure resume won't work until you're over 25mph anyway, same as set.

If I lift off, as I typically do when setting or resuming cruise, it will clear the problem anyway as it always does. If I don't I would expect the same rocketship effect as today.
But I'll see if I can manage that test somehow. I have an idea how....

[PsYcHe]

You're on a fly by wire throttle, so the cruise control sends its own signals to the throttle/ECU.

Can't remember.. did you do the new throttle sensor like Jim had fitted recently? I'm sure there's a VCDS measuring block for pedal position, might be worth just playing with that when cold to see if it gives the figures you expect.

[HPsauce]

I have a replacement throttle pedal sensor on hand, awaiting fitment.
It's been on hold until the catalyst was sorted in case that changed symptoms - it hasn't.

I've tested the throttle position readings several times with VCDS and it's always appeared perfect.

The intriguing thing is that, as explained above, if you are on cruise you can override speed upwards by pressing on the loud pedal, which is why I did the test today. Basically the pedal was already pressed a lot but the car was acting as if it was only slightly down, which is the main part of the problem. As soon as I "set" cruise (without moving my right foot) it acted as if the pedal really was where it was and shot off!
So effectively, turning on the cruise control, or more precisely "setting" it, cancelled the problem and restored "normal service". Lifting my right foot then putting it down again does the same, but less violently.

I'm trying to understand what this "reset" effect from setting the cruise tells us about the problem.
It does suggest to me that the pedal sensor is OK, but that the signal from it is being processed incorrectly - a software problem?

[ainarssems]

It does sound like a accelerator pedal sender issue or associated wiring. There are two potentiometers in the sender for redundancy and safety. Both potentiometers go in different directions, for one resistance increases as you press pedal, for other it decreases, it is this way for safety and for more reliable reading. If both resistances does not match same pedal position engine will operate with reduced power output. If the difference is too great it will trigger fault code, otherwise it is reset when pedal released and if next time values are within specified range it will return to normal operation. Looks like setting cruise also resets pedal reading.

[HPsauce]

Interesting Ainars. All my tests with VCDS show both potentiometers behaving properly, but what you describe is pretty much exactly the symptoms though definitely no fault codes.
I guess replacing the sender is the logical next step, for which I am prepared!

[Delboy]

That description of operation describes exactley how your car can show these problems, if one pot is slighty iffy then you would get the reduced power that he mentions that clears in release of the pedal, is it possible to log the pots in VCDS and go for drive, then once you have a fault scenario you can timestamp I vcds so the log shows when the fault was so you may find it easier lookng through the log later.

[HPsauce]

As I already have a replacement I'll just swap it, checking readings before and after sitting on the drive.
It's not reproducible enough to set up with the laptop and go for a drive.

Might have a look at how easy it is to swap this afternoon as it's sunny, if it looks tricky I'll get the garage to do it.

[ainarssems]

I don't think VCDS show direct individual readings from potentiometers only calculated pedal position but could be wrong

[HPsauce]

It shows both (block 62, items 3 and 4 IIRC), but I'm going out in a minute to check again what the values are and how they change with the pedal movement.

[HPsauce]

Confirmed. Block 62 shows 4 values.
The first two are the throttle valve position and they "oppose" adding up to about 100%.
The second pair are the pedal position and one is roughly half the other.

All behaving as expected......... :Confused:

Now going to take the knee panel off and have a look at access.

[HPsauce]

is it possible to log the pots in VCDS and go for drive, then once you have a fault scenario you can timestamp I vcds so the log shows when the fault was so you may find it easier lookng through the log later.
I'm beginning to think I'll have to do that, but it will probably take whole a load of test runs to get anything useful. :(

I added more info earlier after taking the knee panel off, but it's disappeared. :Confused:
In summary I can see the unit and its moving properly, no slack no fouling, but is a pig to get at with a big air duct in the way.
I can only see one retaining screw for the duct and taking that out makes no difference, I think all the carpets and trim panels will have to come out first and reveal more fixings.

When it's a bit more springlike I'll probably do that to clean all the carpets etc. after winter and have another look.
If I still can't get the duct out I'll probably hand it over to my garage. I'd take all the trim out anyway before doing that. :rolleyes:

But a test run logging the pedal position while recreating the problem would be very instructive. I just have a suspicion that it will show the position signals are correct..... :tuttut: So the sooner I can achieve that the better.

[HPsauce]

Could, and if so how, petrol brand make a difference? :Confused:

For the last few days it's definitely been worse (more reproducible) than normal.
The last tankful I got ( about 2 weeks ago, desperate and on the A12!) was BP 97.

Yesterday, under extreme pressure from SWMBO aggressively wielding a Sainsburys 10p a litre discount voucher, I filled up with Sainsburys 97 in Peterborough. (She did pay :cool: )
Since then I'll swear it feels more urgent and no obvious symptoms since in about 4 assorted trips (100 miles total) yesterday and this mornings station run.

[Delboy]

I honestly feel that's clutching at straws, but if it does indeed turn out to be the cause then great.

There was a episode of fith gear where they tested the top brand juices and surprisingly Bp was the worst performing out of the top branded fuels, shell v power nitro came top.

From worst to best there was 5bhp difference in a golf gti so yes fuel is different, but is it bad enough to cause to problems you have had not so sure

[HPsauce]

I honestly feel that's clutching at strawsWell yes and no, more trying to understand the symptoms and see if that helps with a diagnosis.
This is a long-running thread and I noticed early on that changing fuel "seemed" to have an effect, but I didn't understand when and how and it clearly wasn't the whole answer.

Since then I've done loads of things and still got no nearer to a resolution. The recent observation about the response to setting cruise on is new information and I'll investigate that more. The fuel factor is an old one that isn't consistent enough to analyse as for some time now I've been running almost exclusively on Shell V-power.
I might try a tank of standard 95 soon.

[HPsauce]

I might try a tank of standard 95 soon.Circumstances forced me into a fill-up with BP 95. :-(
No severe sluggishness since then, but still occasional throttle inconsistencies immediately after a cold start.

Today I decided to redo Throttle Body Alignment, repeated a few times to be certain.
It ran quickly but I noticed that the lower adaptation value, stated by VCDS to be 10% or less, was more like 15% before and after. Any observations anyone? :Confused:

[HPsauce]

The saga continues............
After no serious symptoms for some time, today I headed off to buy some petrol. After maybe 200 yards from a cold start I turned left slowly at a T-junction and it was sluggish again.
Next junction (where I had to stop) was only 20 yards further so no chance to experiment; after that it was fine.
BUT the tank was pretty empty, showing 0 miles but probably well over 10 litres left. And the first 200 yards were uphill.................

Put in about 75 litres of Momentum (to flush out the BP 95) and it's been fine since.

[HPsauce]

But this evening I managed to do the cruise control thing again.
Hadn't driven for several hours and headed out with a cold engine and just got a "feeling" in the first few yards that it wasn't behaving totally properly.

So, got up to 30mph and set the cruise control. A few yards later braked and turned slowly left then almost immediately right at T-junctions.
It was very sluggish so I let the speed build up gently to just over 25 (it did change gear) and flicked the cruise on. Kick up the backside as my right foot was still a fair way down!
Lifted off smartly as I was still in a 30 limit with the 40 sign just a few yards ahead.

If I can manage it, the next time I'll try to get the car moving faster than the stored cruise setting and see what happens then when I switch it back on.

[Green Goblin]

Just a thought...

Might be worth checking for sluggish flap pivots as per this (http://forum.a8parts.co.uk/showthread.php?t=9857) thread. Maybe dirty and/or sticking?? Bit of a stab in the dark but you never know!

[HPsauce]

And nearly a year has passed with little comment from me, but I got the symptoms again yesterday, rather more oddly this time.
And yes, it has happened occasionally over the last 9 months, I just haven't posted.

We went out for lunch, a 25-mile drive along main roads and M25 to get there (near Egham). All totally normal.
Returned mid-afternoon and being a Friday avoided the M25, so just "pottering" along back roads mostly around 30 or 40mph.

Over half way home, car totally warmed up, drove through Old Windsor then Slough and headed north towards Stoke Poges. After a roundabout got up to around the 40mph limit normally and into 5th gear but then after a little while noticed the engine in higher revs, almost as if in sport mode, but still proceeding gently (pretty sure not on cruise control). The revs meandered up and down a bit then returned back to normal after a little while, below 2000rpm, presumably in top gear.

I did try Sport mode a bit later at similar speeds and while it upped the revs initially it dropped back quite quickly to normal as I was driving gently.

All seems very odd, thoughts anyone?

It's almost 3 years and about 20,000 miles since I had the gearbox fluid/filter changed so maybe that's due another go? And I am planning (not yet arranged) to take the car to Guy sometime this spring (pre Wales/Ireland) for a thorough service and "going over"....

[Architex_mA8tey]

All seems very odd, thoughts anyone?

It's almost 3 years and about 20,000 miles since I had the gearbox fluid/filter changed so maybe that's due another go? And I am planning (not yet arranged) to take the car to Guy sometime this spring (pre Wales/Ireland) for a thorough service and "going over"....

The gearbox oil change is recommended every 40k miles and perhaps every 5 years if less mileage is done, but have you checked all vacuum pipes for damage, and the correct operation of the manifold flaps and bellows etc, it does sound much more like something like that, or even blocked fuel filter or dodgy fuel? :Confused:

[HPsauce]

I've checked the flaps/bellows regularly (though not recently) and everything always works perfectly.

Fuel filter was changed at the last service. Fuel is either Tesco Momentum or Shell V-power, can't recall which I filled up with last. Tank about half full.

[Mechcanico Lee]

Ba Jesus !!! Just read through all the posts on this fault ........

The fuel type .....shell v power , supermarket plonk grade , whatever grade !!! it's NOT fuel grade causing this .... yes there is a difference in qualitys of fuel .....will it make a car go dead throttle on take off , then come back again and be all ok again ...... what ???have the octane fairys just sprinkled some magic glitter on that tank full and made it all ok again ....no chance .... just think it through .... think Delboy said it back there somewhere ., "clutching at straws " or some such , sorry for the bluntness , don't mean to insult your intelligence by the way .

The fault code in Abs 00116 gear ratio not recognised or some such , I think it's a big tell tale .... some of the good techs on here glanced on it .

So abs ecu is looking at road speed and individual road speed from each wheel to work out any traction control interventations , gearbox ecu will be receiving this info via can network , engine ecu will be looking at both abs ecu and gearbox ecu .....so far so good ??
So could we have conflicting messages what road speed is via abs to what road speed the gearbox thinks is the correct gear it should be in .

Here's where I would go ..... does the car have the button to disable traction / esp ..... if yes press it then start your normal drive cycle , see how it goes

Next test if it's still same after disabling esp .....

Un plug 1 of the abs sensors at the connector ....lets default the brakes to standard operation eh , if you lose speedo reading , re connect that one and un plug another , I don't know which one is the ' master ' sensor so trail and error , you do not want to lose speedo because the gearbox will just go to default and that's no good for our testing , yes abs light will be on and other lights , doesn't matter for our tests .

Are the tyres around the same wear levels ?
Does it have different brands of tyres on the same axle ?
Do you ever get a strange ' flutter ' on the brake pedal as you come to a near stop ?

Some things to go at for now

[HPsauce]

Ba Jesus !!! Just read through all the posts on this fault ........
Thanks for making the effort. +++
The fault code in Abs 00116 gear ratio not recognised or some such , I think it's a big tell tale .... some of the good techs on here glanced on it . Actually 01119 - Gear Recognition Signal 35-10 - - - Intermittent
And others have experienced/reported this but no significant outcomes. :Confused:

So abs ecu is looking at road speed and individual road speed from each wheel to work out any traction control interventations , gearbox ecu will be receiving this info via can network , engine ecu will be looking at both abs ecu and gearbox ecu .....so far so good ??
So could we have conflicting messages what road speed is via abs to what road speed the gearbox thinks is the correct gear it should be in . I've been thinking along those lines too, it definitely (I'm a computer guy) has all the symptoms of software behaving unusually, but with no clear cause/logic.

Here's where I would go ..... does the car have the button to disable traction / esp ..... if yes press it then start your normal drive cycle , see how it goes Good thinking, I haven't tried that, though the fault is fairly infrequent and not reproducible - it just surprises me every now and again.
(I have I think posted that resuming cruise control directly affects it, again linking to the software interaction ideas)

Next test if it's still same after disabling esp .....Logical. You mean re-enabling presumably. Though as noted, problem is not easily triggered.

Un plug 1 of the abs sensors at the connector ....lets default the brakes to standard operation eh , if you lose speedo reading , re connect that one and un plug another , I don't know which one is the ' master ' sensor so trail and error , you do not want to lose speedo because the gearbox will just go to default and that's no good for our testing , yes abs light will be on and other lights , doesn't matter for our tests .Not sure I could do that or want to risk it.

Are the tyres around the same wear levels ?
Does it have different brands of tyres on the same axle ? All identical brand/type/design, same wear etc. Happens on both winter and summer tyres/wheels - currently on winter 18's. Summer is FE 20's.
Do you ever get a strange ' flutter ' on the brake pedal as you come to a near stop ? No.
Some things to go at for nowTa muchly. :D

[HPsauce]

Just to add that I had thought of punching the ESP off switch when it happens but reaching for it would probably disturb my right foot on the throttle and reset back to normal anyway, so I haven't done it yet.

But I'll think about starting off a journey that way.

[Mechcanico Lee]

Defaulting the abs to normal brakes .....how old are you , I'm 45 and drove loads of cars without abs in my younger days when let's be honest ....that's when you needed it more , scragging around on two wheels and a door handle !!

Risk it hehe
When was the last time you panicked and the abs saved your life

What did we all do in the days when cars did not have abs ..... how did we all manage ??? Oh my
I'm telling you the steps I would take to diagnose that problem , if you do not want to 'risk it ' ....replace all abs sensors , replace all abs reluctor rings maybe part of the cv joints or wheel bearings if reluctor is part of the bearing and if it's still got the fault .... well what a waste .....lets guess at some more parts ...


My way will cost nothing but time , carry out relevant tests .... default some systems to basic programmes .... rule out ....move on to next test , no fitting of parts till customer runs out of money brigade ...( I see this everyday nearly )

Now appreciate the fault is very intermittent but it's been going on since 2013 so a few weeks of driving in default modes is liveable I think

You see switching esp off will only kill the traction side , if there is miss match of signals or voltage spikes from abs control having it enabled is not ruling it out so that's why I say it needs to be shut down IE un plug a sensor .

The cruise control forcing through the fault ...... Pedal position sensor does Spring to mind here like already said , but also it could force through the incoherence of whatever data is causing the original ' dead pedal ' all depends on the strategy of that system

Try this as a test , drive along with foot on accelerator ,with your left foot just rest on the brake pedal not enough to be braking but enough to bring brake lights on if you can see it in the window from the light in the back window .

Does it momentarily kind of kill the engines power , as I say your not braking but supplying the engine and abs ecu with the braking signal from the pedal switch , it may be nothing to do with your fault but have seen similar ' dead pedal ' issues when it's been the brake pedal switch right on the threshold of coming on whilst accelerator is being pressed ..

Does your fault tend to do it after a period of braking / slowing down then getting back on the gas to accelerate again .

Have you had it do it when you have let off the power but not done any braking then back on the gas pedal .

[HPsauce]

Defaulting the abs to normal brakes .....how old are you , I'm 45 and drove loads of cars without abs in my younger days .

Not bothered about no ABS, just about my ability to disconnect the cables without messing something up.
I'm way older than 45 and suffer from arthritis so I'm not going to scrabble around under the car! :tuttut:

[HPsauce]

Try this as a test , drive along with foot on accelerator ,with your left foot just rest on the brake pedal not enough to be braking but enough to bring brake lights on if you can see it in the window from the light in the back window .

Does it momentarily kind of kill the engines power , as I say your not braking but supplying the engine and abs ecu with the braking signal from the pedal switch , it may be nothing to do with your fault but have seen similar ' dead pedal ' issues when it's been the brake pedal switch right on the threshold of coming on whilst accelerator is being pressed ..
Clever, I'll try that. +++

Does your fault tend to do it after a period of braking / slowing down then getting back on the gas to accelerate again . Yes, but not always.

Have you had it do it when you have let off the power but not done any braking then back on the gas pedal .Not sure, but I think so.

Thanks for applying brain power and logic to this. :cool:

[Mechcanico Lee]

Not bothered about no ABS, just about my ability to disconnect the cables without messing something up.
I'm way older than 45 and suffer from arthritis so I'm not going to scrabble around under the car! :tuttut:



Arrrrr right you are , thought it was you was worried to drive with no abs , all the previous ' ripping you to shreds ' bit ...... I take it all back ..... carry on nothing to see here ......

[HPsauce]

I'd say 90% of my driving mileage has been in cars without ABS and an even higher percentage without ESP. :cool:
That said, I do occasionally like trying out the ESP (in safe conditions) just to see how competent it is, and I'm usually amazed!

I can't actually recall the last time ABS kicked in on either of my cars, it was quite a while back. The override I see most often (and even that is pretty rare) is the traction control on my old Focus, mainly because it's a bit too sensitive (the first electronic system Ford made back in the last millennium), especially when the tyres are a bit worn on a slippery road. :tuttut:

[steamship]

Here's where I would go ..... does the car have the button to disable traction / esp ..... if yes press it then start your normal drive cycle , see how it goes

Not sure if this helps Andrew, but I was out for a short leisurely drive yesterday and disabled the ESP at the very start. I have the same issue as you, but somewhat more regularly. Most of the trip was fine, except twice at junctions. One crossroads and one blind junction. As with you, when moving off, there were lots of revs, but little acceleration. A blip of the throttle restored it to normal function.

From all the suggestions previously mentioned, I still think the throttle position sensor may be the culprit. I even bought one from the forum sponsors, but haven't fitted it yet. Jim mentioned about a similar scenario, but his I think was more a one-off, and I believe his was related to corrosion of some terminals in the ECU box.

My reasoning for thinking it's the TPS is how I approached those junctions. Driving along around 40mph and then just easing off the throttle on approach to the junction, and just using the brakes to bring the car to a full halt. Someone mentioned that the sensor has a double rheostat, one registering from 0-100 and the other 100-0, and that combined they should give a 100% reading. If not, you don't get full throttle. That at least sounds plausible, but until I change mine and dismantle the old one, I can't be sure.

[HPsauce]

Yes, I've got a replacement TPS as well, also from our sponsors. ;)

Being not a great mechanic (and arthritic to boot) I'm going to hand it over to Guy to fit when I take the car to him to be serviced sometime soon (not booked yet).

BUT, what I have done is plug in my laptop and measure the throttle sensors, they are "roughly" as you describe. In static tests it's always 100% reliable and I haven't got round to logging it while driving, largely because it's so intermittent.

[steamship]

Yes, I've got a replacement TPS as well, also from our sponsors. ;)

Being not a great mechanic (and arthritic to boot) I'm going to hand it over to Guy to fit when I take the car to him to be serviced sometime soon (not booked yet).

BUT, what I have done is plug in my laptop and measure the throttle sensors, they are "roughly" as you describe. In static tests it's always 100% reliable and I haven't got round to logging it while driving, largely because it's so intermittent.

Could you tell me what channels to measure, and I'll see if I can do it. I only found one test for it and that was when static. It was also just a single reading, not dual.

[HPsauce]

See here: http://www.ross-tech.com/vag-com/m_blocks/060-069.html Group 62 shows all 4 values for pedal and throttle body.

[steamship]

Had a look at that, and also managed to get Elsa running again on the other laptop. Having read through what it says, I think my test sorts of confirms that my TPS is kaput. See below for results:


http://forum.a8parts.co.uk/attachment.php?attachmentid=12494&stc=1&d=1456251354

The Red and Green traces are the throttle valve in the engine bay, and is working correctly as one is a mirror of the other. If I've read the details on Elsa correctly, the Blue trace on the other hand should be a mirror of the Purple trace, which it clearly ain't. Time to dig out the replacement, methinks!

[HPsauce]

Did you do that with the engine running or just ignition on? Might try mine again when I have time.

[steamship]

Did you do that with the engine running or just ignition on? Might try mine again when I have time.

Ignition on only.

[HPsauce]

According to this, that is correct: http://wiki.ross-tech.com/wiki/index.php/18047/P1639/005689

There are 2 sensors in the accelerator pedal, both should increase in the same direction as the accelerator is pressed but they have different scales. This means one counts from 0 to 100, while the other one counts from 0 to 50.

[HPsauce]

Worrying development this morning - limp mode! :tuttut:

Jumped in the car, started it and selected reverse (to back out of drive) maybe a tad quicker than normal.
Nothing immediate (usually selects and creeps back) so I "think" I squeezed the throttle pedal. After a second or so there was a bit of a clunk and it moved backwards.
Another clunk at the end of the reverse when I changed to Drive - not sure if it was as I moved into Neutral or into Drive.

Headed off and it was "sluggish" going up the hill. It was cold so my DIS had faded out.
After a little while I could see the gears all highlighted in red on the DIS, though by then it was driving reasonably normally. All in 30mph limits though.
Just over a mile from home (after more hills!) I found a wide level place to pull over and stop.

Ignition off, restarted after 5 seconds, all fine. Car drove totally normally from there on - a journey of about 10 miles including some motorway. Returned about an hour later by the same route and all was fine.

What do we think? One-off on a cold morning due to selecting gear too quickly, dodgy F125 switch or something worse? :Confused:

Haven't plugged laptop in yet.........

[Architex_mA8tey]

It does sound rather like a dodgy F125 switch doesn't it

[HPsauce]

If that's all I'm not too worried, I'll get it down to Guy sooner rather than later, presumably he can deal with that?

Would that be consistent with my long tale of weirdness?

[HPsauce]

It does sound rather like a dodgy F125 switch doesn't itConfirmed by VCDS scan. Clean apart from 2 codes, one of which is a regular, the other the F125. :(

The usual: 01119 - Gear Recognition Signal 35-10 - - - Intermittent
The expected: 17090 - Transmission Range Sensor (F125): Implausible Signal P0706 - 35-00 - -

I didn't clear it, though maybe I should?

[HPsauce]

I cleared both codes and had a little potter back and forwards on the driveway, all fine and no codes returned.

Wait and see at this stage I guess, next trip is probably tomorrow afternoon/evening.

[Adrian E]

F125 can come and go - moving it to R or D will make it likely to come on. If you start a journey and get to D without triggering the fault it won't come on at all until you next move the gear selector

Be warned there's 2 types of switch with different plugs so order from TPS with VIN to make sure you get the right one. Costs about £150 IIRC and bit of hassle to fit as box needs to be dropped a little to access I think, so one exhaust pipe off from memory

If it's due a box service it makes sense to do at the same time as it'll save some labour

[HPsauce]

Adrian, I'll probably get it all done by Guy sometime soon.

Had a few journeys since the "glitch", all totally fine. :Confused:

[The_Laird]

Mine does this once in a blue moon. If there is a pattern to it, it seems to be when I've reversed the car out of the garage to wash it and then driven it back in and left it. Next day it very occasionally goes into limp when I engage reverse again. Turning the ignition off and back on again always clears it.
I'll probably get it done at the the next gearbox service later this year.

[moltuae]

If there is a pattern to it, it seems to be when I've reversed the car out of the garage to wash it and then driven it back in and left it. Next day it very occasionally goes into limp when I engage reverse again.

Mine used to do that when I first bought it years ago. Disconnected and cleaned the F125 switch connections; never done it since.

[HPsauce]

Mark, was that just the wiring plug (8-pin I believe) or did you remove the unit from the gearbox?

[Adrian E]

Mark, was that just the wiring plug (8-pin I believe) or did you remove the unit from the gearbox?

It can be done in situ, although on a ramp would help!

For an intermittent connection issue that appears unrelated to moving the gear selector, it'd be worth a try. If the symptoms seem to relate to movement of the gear selector it's more likely to be mechanical wear in the unit so no amount of cleaning the pins will help.

[HPsauce]

The limp mode the other day is the only time ever that moving the gear selector has had any unexpected effect.

[moltuae]

Mark, was that just the wiring plug (8-pin I believe) or did you remove the unit from the gearbox?

Just the wiring plug. Unplugged it, cleaned the pins, applied some contact lube and connected/disconnected it a few times.

The plastic undertray was missing when I bought the car, which I think probably left the connection a little more exposed than usual.

[HPsauce]

limp mode! :tuttut:

Jumped in the car, started it and selected reverse (to back out of drive) maybe a tad quicker than normal.
Nothing immediate (usually selects and creeps back) so I "think" I squeezed the throttle pedal. After a second or so there was a bit of a clunk and it moved backwards.
Another clunk at the end of the reverse when I changed to Drive - not sure if it was as I moved into Neutral or into Drive.

Headed off and it was "sluggish" going up the hill.
.
.
.

Ignition off, restarted after 5 seconds, all fine. Car drove totally normally from there on
.
.
.
.
Haven't plugged laptop in yet.........
Same again today, I'm expecting the same codes as before.

The car had been sat unused for a couple of weeks prior to starting it today, maybe I should have let it idle briefly and get the fluids moving before selecting reverse?

[HPsauce]

Same again today, I'm expecting the same codes as before.

And that's what I had:

The usual: 01119 - Gear Recognition Signal 35-10 - - - Intermittent
The expected: 17090 - Transmission Range Sensor (F125): Implausible Signal P0706 - 35-00 - -

[HPsauce]

I'm having this looked at, possibly replaced. This problem has been niggling at me for over 3 years and whilst I can't say that "money is no object" I do want it fixed!

Does anyone know (roughly) what the price of a NEW F125 switch is and how many hours labour by a garage (assuming Audi specialist who know what they are doing) the job will take?
(I know I can get a used one from our sponsors for about £100 so presumably a fair bit more than that new and the Audipages "amateur" swap took several hours)

[HPsauce]

Be warned there's 2 types of switch with different plugs so order from TPS with VIN to make sure you get the right one. Costs about £150 IIRC and bit of hassle to fit as box needs to be dropped a little to access I think, so one exhaust pipe off from memory.

I've been told £900! And several hours labour. :eek:

[Adrian E]

I've been told £900! And several hours labour. :eek:

I've left you a rambling voicemail!

[HPsauce]

I've left you a rambling voicemail!

Thanks, got that. Minimal mobile reception where I am at present. Mines an FBG gearbox.

I've been told parts are on backorder as well, so I'm getting the car back tomorrow without that done, though I think they've checked and cleaned the plug, which was OK.

[HPsauce]

I've been told parts are on backorderI think they've got some part numbers mixed up, they should have these. :tuttut:
Thankfully Adrian has given me the right numbers (having had this done not so long ago) and I've passed them on. +++

The service managers description of the work corresponded with Adrian's description, so I think they have the right job, just an error in passing on the part number.

[steamship]

I've been told £900! And several hours labour. :eek:

Was trying to find some info on this late last night, but only one I could find was related to a modern Audi (A6 Allroad), and the cost was around £700. Hoping they made a typo in the part number to come to that price!

[ainarssems]

It appears there are 2 possible switches depending on gearbox code, one with 8 pin plug about £350 and one with 10 pin plug about £180

[HPsauce]

It's the 10-pin for my FBG gearbox - 01L 919 821 B at £153.09 plus VAT. ;)

[steamship]

It's the 10-pin for my FBG gearbox - 01L 919 821 B at £153.09 plus VAT. ;)

Now that's more like it. When I bought one from the forum sponsors back in 2013, it was £110, although can't remember if it was 8 or 10 pin.

[HPsauce]

They have a couple for sale around that price, one is stated as 8-pin the other looks like it's probably the same.

Given the amount of money I'll be paying to a garage for their labour the extra for a new one is worth it to me, even if they did have a 10-pin one.

[HPsauce]

Oh well, too late to get all this sorted out before the bank holiday, so I got the car back today. Hopefully it can be done next week.

Interesting comment I got re leaking seals though (I've been suffering from the usual burning smells), they replaced the rear one on the gearbox/diff and commented that it was different to what was fitted before.
Checked and rechecked and were quite sure what they fitted now is correct.

I recall some discussions on variations of the seals, was it that one? If so is it a revision or are there differences in other components too?

[Adrian E]

Tail shaft on the centre diff is the one that varies depending on whether the tailshaft extension has a later design to accommodate a lip on the seal. Most late cars seem to have it from the factory but it still bloody leaks with a new seal!

[HPsauce]

Thanks Adrian, that sounds like the one. Must have been changed in the past and had the wrong one put on.
Leaking drive shaft seals is "just one of those things" that you have to live with as a D2 owner. :ROFL:

[HPsauce]

Oh well, too late to get all this sorted out before the bank holiday, so I got the car back today. Hopefully it can be done next week.

A very long week, well over 6 months in fact, but it's done now, last Friday in fact. +++

As noted in other threads, currently rather active, first reactions are very good, but only time will tell. The 01119 error has not yet returned since the job was done.
This is the current discussion, started by David: http://forum.a8parts.co.uk/showthread.php?t=12221

[HPsauce]

Horrible cold wet morning and I went out early in the S8, it behaved impeccably, absolutely no hint of throttle misbehaviour. :cool:
(And a quick VCDS check confirmed that the 01119 error hasn't come back either)

[HPsauce]

Another 3 days, a few more trips, still behaving and still no 01119 error. +++

I'm seriously convinced that all those comments about cleaning ABS sensors etc. are just coincidental and that the real cause of the 01119 error is a worn F125 switch.

[HPsauce]

Good news and I hope - for your sake - that what is possibly the longest running thread on a single problem will come to an end. +++Just spotted this from well over 2 years ago. :ROFL:

[notorious]

Glad to know all was resolved. Will be cleaning f125 connector contacts on my car to fix 01119 error preventively. If it won't help will change the whole switch. Epic thread.

Edit: Is the electrical connector of F125 switch easily accessible?
(I wanted to start from replacing only the connector to new and then replacing the full switch if it does't help?)

[HPsauce]

Glad to know all was resolved. Will be cleaning f125 connector contacts on my car to fix 01119 error preventively. If it won't help will change the whole switch. Epic thread.

Edit: Is the electrical connector of F125 switch easily accessible?
(I wanted to start from replacing only the connector to new and then replacing the full switch if it does't help?)

I think the connector on the fly lead is easy to get at, several people have opened it up and checked/cleaned the contacts with mixed results. The problem I and others have had is wear/corrosion on the moving parts INSIDE the switch.

[notorious]

Understood. Will change the full switch then.

[David's8]

Sergei, you are not known for doing half-hearted jobs +++ Given the construction of the switch (see my thread with photos) it doesnt give the impression that a squirt of electrical cleaner or any other form of repair would do the business. With mine, one (at least) of the contactors was damaged. It MIGHT have been possible to have built it up with solder but i wouldnt have given tuppence for it lasting. The F125 switch is £153 (IIRC) + VAT so it should give you peace of mind for another 100k +++

[notorious]

Went to order the switch. Cheers David.

[MikkiJayne]

Given the construction of the switch (see my thread with photos) it doesnt give the impression that a squirt of electrical cleaner or any other form of repair would do the business. With mine, one (at least) of the contactors was damaged. It MIGHT have been possible to have built it up with solder but i wouldnt have given tuppence for it lasting.

Agreed. Cleaning the inside of mine has solved the problem for now, but its not a long term solution as the contacts are clearly wearing away. I was curious so it was worth a try but I have no idea how long it will last. It may be another 100K, but it may be a few weeks. Certainly if you have to pay a garage 4-5 hours to do the job there is no point whatsoever in skimping on £180 for a new switch.

[HPsauce]

Another 3 days, a few more trips, still behaving and still no 01119 error

And another week has passed without incident +++. Clean VCDS scan - well apart from a low voltage in the alarm siren.
So as I said earlier:
I'm seriously convinced that all those comments about cleaning ABS sensors etc. are just coincidental and that the real cause of the 01119 error is a worn F125 switch.

[HPsauce]

Agreed. Cleaning the inside of mine has solved the problem for now,I did wonder, but forgot to ask yesterday. Just assumed as you turned up in the S8 to tow another away that it was behaving itself. :ROFL:

[briang9]

And another week has passed without incident +++. Clean VCDS scan - well apart from a low voltage in the alarm siren.
So as I said earlier:

glad to hear you got this sorted Andrew+++

[MikkiJayne]

2. Pulling out of a side road and accelerating the car only speeds up "gently" not "urgently" as I expect. No ABS/ESP warnings or symptoms. Only seen within the first minute or so of driving the car and not always by any means.


Interestingly, since having 'mended' my F125, mine is now doing this most of the time. The first 50% of the throttle does very little, but prod it a bit further and it takes off like a rocket. It happens mostly in 1st which is very annoying, but also randomly in other gears. If I'm in town pootling around at 30 and slow down for something it'll take a hefty prod to make it move, at which point it changes down to 2nd and goes a bit nuts. Its much better behaved in tiptronic, to the point I had to tow the FE home entirely in tip otherwise it would barely move. No codes either.

Time for a new switch methinks...

[moltuae]

The first 50% of the throttle does very little, but prod it a bit further and it takes off like a rocket. It happens mostly in 1st which is very annoying, but also randomly in other gears. If I'm in town pootling around at 30 and slow down for something it'll take a hefty prod to make it move, at which point it changes down to 2nd and goes a bit nuts.

Check your brake pedal switch too. Had a similar problem with mine a few years ago, turned out to be iffy brake pedal switch contacts. I noticed the fault would tend to occur more after firm braking and tapping/wiggling the brake pedal before setting off again seemed to alleviate it.

[HPsauce]

Interesting, though not exactly the same as my symptoms, nonetheless very similar.
It all points to the F125 switch causing odd behaviour that doesn't throw an error.

One interesting test that you might be able to do is to set a cruise control speed at some point early in a journey (say about 35mph) and then when the symptoms appear at a lower speed turn cruise back on once at/over 25mph.
In my case this instantly (without moving my right foot) reinstated full power mode.

[Adrian E]

Just to add to that theory, there was a note on a service record for my S8 that the previous owner reported an unresponsive throttle.

Camspec didn't detect an issue during the time they had it for cambelt etc, but when I bought the car soon after I had the F125 flag up.

As I changed it pretty soon after first detecting it, it might explain why I never experienced the poor/non-existent throttle response to connect the potential causes of issues together?

[steamship]

Interestingly, since having 'mended' my F125, mine is now doing this most of the time. The first 50% of the throttle does very little, but prod it a bit further and it takes off like a rocket. It happens mostly in 1st which is very annoying, but also randomly in other gears. If I'm in town pootling around at 30 and slow down for something it'll take a hefty prod to make it move, at which point it changes down to 2nd and goes a bit nuts. Its much better behaved in tiptronic, to the point I had to tow the FE home entirely in tip otherwise it would barely move. No codes either.

Time for a new switch methinks...

After I had the faulty F125 switch problem (dashboard lit up), I had it replaced with one from the forum sponsors. That has worked fine most of the time, but I too started experiencing the same issues as Andrew, and resolved it with the same quick stab on the pedal, although I only tend to experience it in the lower gears like moving off from junctions or having slowed at a roundabout.

Check your brake pedal switch too. Had a similar problem with mine a few years ago, turned out to be iffy brake pedal switch contacts. I noticed the fault would tend to occur more after firm braking and tapping/wiggling the brake pedal before setting off again seemed to alleviate it.

Curious you mention this as I've had error codes about the brake switch before and had it replaced with a brand new one. However, I still get error codes relating to the brake switch. In fact, I get it in Engine (01) 16995, Transmission (02) 17087 and ABS (03) 00526. Is it possible that the connector on the loom could be loose and not giving me 100% contact? If so, can the connector be opened up and the crimps tightened, although from memory I think they are round in shape.

[MikkiJayne]

Curious you mention this as I've had error codes about the brake switch before and had it replaced with a brand new one. However, I still get error codes relating to the brake switch. In fact, I get it in Engine (01) 16995, Transmission (02) 17087 and ABS (03) 00526. Is it possible that the connector on the loom could be loose and not giving me 100% contact? If so, can the connector be opened up and the crimps tightened, although from memory I think they are round in shape.

Likewise. I've just changed the brake switch because all three modules were complaining about it. With the new switch only the ABS unit logs a fault. I wonder if that is still affecting the ECU?

Further diagnostics needed +++

[ainarssems]

I find that that error is always in ABS unless you press brake pedal after switching on ignition. So try that- switch ignition on, press and release brake, connect VCDS and scan ABS for fault codes, brake switch error should not be there.

[MikkiJayne]

Will do thanks +++

[Adrian E]

I find that that error is always in ABS unless you press brake pedal after switching on ignition. So try that- switch ignition on, press and release brake, connect VCDS and scan ABS for fault codes, brake switch error should not be there.

That's weird - never had to do that with mine? Maybe it's a PF thing?

[HPsauce]

I find that that error is always in ABS unless you press brake pedal after switching on ignition.Yes, known idiosyncrasy.+++
(I think Ross-Tech have a note on it somewhere) So try that- switch ignition on, press and release brake, connect VCDS and scan ABS for fault codes, brake switch error should not be there.Standard procedure that I always use. :cool:

[MikkiJayne]

That's weird - never had to do that with mine? Maybe it's a PF thing?

You might be right there - I've never noticed it on mine (FL) before the switch broke, but the Titanic (PF) did seem to behave like that even after a new switch. I'll try it in a bit :)

[MikkiJayne]

Mostly normal service resumed :D

When I fitted the replacement brake switch I got it in the perfectly wrong position (yes, there is such a thing!). It has two contacts - one normally open (for the brake lights), and one normally closed (for the ECUs). The ECUs expect to see both contacts change together so they know the switch is working. I'd managed to get it in just the wrong position so the normally open was open, but just enough pressure on it for the normally closed to also be open! The ECUs knew something was up so all got in a grump :D Wound the switch in another half turn and everything is fine now - no codes, and enough oomph from stationary to wake up the ESP +++ I wish I'd figured this out before towing the FE home :eek3: Steamship - that could well be your issue too?

Curiously the cruise control still isn't working, despite the ECU seeing all the switch contacts operating, which is odd. Need to do a bit more digging on that.

No brake switch error code on power-up either, so that must be a PF thing :)

[HPsauce]

No brake switch error code on power-up either, so that must be a PF thing :)Pretty sure I get it on my FL. Must check sometime.
Maybe my brake switch is faulty too.....

[steamship]

When I fitted the replacement brake switch I got it in the perfectly wrong position (yes, there is such a thing!). It has two contacts - one normally open (for the brake lights), and one normally closed (for the ECUs). The ECUs expect to see both contacts change together so they know the switch is working. I'd managed to get it in just the wrong position so the normally open was open, but just enough pressure on it for the normally closed to also be open! The ECUs knew something was up so all got in a grump :D Wound the switch in another half turn and everything is fine now - no codes, and enough oomph from stationary to wake up the ESP +++ I wish I'd figured this out before towing the FE home :eek3: Steamship - that could well be your issue too?

Sounds like something I'll have to try. Question is, how did you test their open/close positions? Was it using VCDS, and if so, how, or just using a multimeter across the terminals?

[MikkiJayne]

I discovered it with a multimeter so since it was already in there adjusted it until it was right also using the meter, but you can see it in Engine measuring block 66 in VCDS too. Mine was only showing one bit changing when I pressed the pedal where there should be two. Once I'd wound it in half a turn both bits changed and everything was happy.

[HPsauce]

Pretty sure I get it on my FL. But no, I don't!
It was actually very difficult to get into the drivers seat and NOT put my foot on the brake pedal, but I managed it.
Did a VCDS scan and no errors, so I guess it really is a PF issue. :cool:

To repeat NO ERRORS. After nearly 4 years of niggling behaviour and the infamous 01119 error. Best Christmas present for a long time. :D

[HPsauce]

I discovered it with a multimeter so since it was already in there adjusted it until it was right also using the meter, but you can see it in Engine measuring block 66 in VCDS too. Mine was only showing one bit changing when I pressed the pedal where there should be two. Just tried that with VCDS. The switch was showing a value of 1000 when untouched.
A VERY LIGHT touch on the pedal (engine off) would change it to 1010 but the slightest bit more and it went to 1011.
That sequence could be reversed by lifting off very carefully.

With the engine running and servo operating it was just about possible to replicate the two stages with great care. But in practice they were near-simultaneous, and I'm sure that on the road they would be.

Does anyone know what those two switches are supposed to do when set correctly, i.e. are they meant to be very slightly apart and if so which way round?

[MikkiJayne]

Thats exactly what mine does now its adjusted properly. One set of contacts acts a mm or so before the other. I think this is deliberate so that the ECUs know whether you're pressing the pedal or letting it go, the same as the TCU knows which direction the F125 is moving.

[steamship]

I discovered it with a multimeter so since it was already in there adjusted it until it was right also using the meter, but you can see it in Engine measuring block 66 in VCDS too. Mine was only showing one bit changing when I pressed the pedal where there should be two. Once I'd wound it in half a turn both bits changed and everything was happy.

Just tried that with VCDS. The switch was showing a value of 1000 when untouched.
A VERY LIGHT touch on the pedal (engine off) would change it to 1010 but the slightest bit more and it went to 1011.
That sequence could be reversed by lifting off very carefully.

With the engine running and servo operating it was just about possible to replicate the two stages with great care. But in practice they were near-simultaneous, and I'm sure that on the road they would be.

Does anyone know what those two switches are supposed to do when set correctly, i.e. are they meant to be very slightly apart and if so which way round?

Thanks very much to both of you. I thought I was being clever when I replaced mine, by measuring how far the old one had been screwed into place. When I did the VCDS scan today, I was getting the 1010 with very little movement, but didn't get the 1011 until I pressed it much further. When I had the engine running, I was getting 1010 all the time. I lifted the pedal with my foot and it went back to 1000. That would explain why the ECUs aren't giving me full power after a gradual braking to a halt. The pedal is not releasing 100%.

Anyway, gave it a full turn, connected up and tried again. 1010 with the slightest touch and 1011 shortly after. With the engine running, same results. Haven't been out in the car yet, but just reversing it round to the front of the house felt so much freer than before.

[HPsauce]

This ancient thread (14th February 2013, 06:01 PM) is uncovering all sorts of intriguing little issues. :cool:

So, how many of us will be plugging in VCDS this weekend and checking Block 66 in Engine while toying with the brake pedal, engine off and on? Someone start a poll (separately please!).

just reversing it round to the front of the house felt so much freer than before.Sean, let us know how it behaves next time you go out.

[steamship]

This ancient thread (14th February 2013, 06:01 PM) is uncovering all sorts of intriguing little issues. :cool:

So, how many of us will be plugging in VCDS this weekend and checking Block 66 in Engine while toying with the brake pedal, engine off and on? Someone start a poll (separately please!).

Sean, let us know how it behaves next time you go out.

There doesn't seem to have been many people with the issue... or they've never seen this thread. It was only because Mark made a comment about the brake switch that prompted me to mention the codes I was getting, with MikkiJayne reporting how she resolved it.

Will keep you updated on how the car responds.

[steamship]

Well, it's been a week now and the car has been used extensively for lugging loaded trailers around, and I'm happy to report that I haven't had a single instance of throttle hesitation.

Not only that, but it just feels so much easier to drive, and I get to hear that V8 burble more as it's more lively.

I haven't scanned it since, so have no idea if there's anything still lurking in the Engine, ABS or Transmission blocks.