Erratic throttle response when cold

[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]

Originally Posted by Mechcanico Lee

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.

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 now

Ta muchly.

[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]

Originally Posted by 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 .

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!

[HPsauce]

Originally Posted by Mechcanico Lee

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.

[Mechcanico Lee]

Originally Posted by HPsauce

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!

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.
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.

[steamship]

Originally Posted by Mechcanico Lee

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.