Erratic throttle response when cold

[HPsauce]

Originally Posted by steamship

I replaced my TPS to try and eliminate the erratic throttle

Did that solve it?
I bought a replacement TPS but decided in the end (supported by VCDS readings) that it probably wasn't the problem as the symptoms weren't of the appropriate pattern.
So if anyone needs one, I have one spare.

Originally Posted by HPsauce

Test drive later

Test drive was flawless. Fingers crossed now and hopefully I'll build up confidence in the car when pulling out of side turnings.

Originally Posted by HPsauce

14th February 2013, 06:01 PM Erratic throttle response when cold
Pulling out of a side road and accelerating the car only speeds up "gently" not "urgently" as I expect.

I started this thread four years ago having had the car just one month! It's been a randomly intermittent problem for all that time.

[steamship]

Originally Posted by HPsauce

Did that solve it?(

No. It seemed fine for about a week or so, and then started playing up again. Considering how awkward it was to replace, I probably knocked the brake switch several times which may have made it work properly for a while.

Since following MJs advice and your pointer to block 66, I sorted it.

I also have a spare TPS, but may keep hold of it... just in case.

[briang9]

Fingers crossed for you guys that this is solved now

[steamship]

Originally Posted by briang9

Fingers crossed for you guys that this is solved now

Fingers, toes and anything else that can be crossed!

[HPsauce]

Originally Posted by steamship

Fingers, toes and anything else that can be crossed!

All of the above and anything else you can think of! Plus several you wouldn't want to....

That said, it is the one thing that logically/analytically fits 100% my remaining symptoms.
Until, to misquote Donald Rumsfeld, we find the next of the unknown unknowns....

[HPsauce]

Originally Posted by MikkiJayne

That said, the V8 D2s do have overly sensitive throttle pedals IMO, making it hard to pull away at any setting thats not 'Driving Miss Daisy' or 'Scalded Cat'.

Originally Posted by Goran

Lol, this is a perfect description of D2 throttle response

And driving away from cold just a while back that's exactly how mine is now. Definitely back in "scalded cat" mode.
So much so that SWMBO who was with me said "what on earth are you doing?"
(The main problem is that the throttle pedal is just SO different to the Volvo which is much more progressive until the turbos are fully wound up)
It calmed down a bit when warmed up, but is definitely lighting up the ESP now at the slightest provocation; hasn't done that for a while.

And "giving it the beans" from even a very low speed the gearbox is changing up smoothly without any oddness.

So I'm beginning to think this brake switch issue (compounded by the F125) was affecting me rather more than I realised. Fingers crossed.

[HPsauce]

Well more than a week has passed and it's still all good, I'm gaining confidence pulling out briskly from T-junctions now. But always considerately so as not to cause any concern or annoyance to the main road traffic.

I'm also noticing a consistency in the "take-off" from stationary or crawling. The very first movement is gentle then a fraction of a second later you can feel the gearbox respond (maybe the torque converter or a clutch adjustment rather than a gear change?) and "tighten up" and off we go suitably briskly.
In the past it's not generally felt consistent, but certainly seems so now.

[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 ..

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 .

I've just been reading back through this incredibly long thread and found this comment from exactly a year ago (#175 21st February 2016, 09:01 PM ) which I'd describe as brilliant. Unfortunately, at the time, I didn't grasp the significance of it.
So, Lee, respect. And sorry it's taken me a year to focus down on your analysis of the problem.

the brake pedal switch right on the threshold of coming on whilst accelerator is being pressed

And I actually said:

Originally Posted by HPsauce

Clever, I'll try that.

But I didn't actually do it.

PS Had a lovely sprightly drive this evening.

[steamship]

Originally Posted by HPsauce

And I actually said:But I didn't actually do it.

Don't beat yourself up Andrew I've been following your thread for a long time, recall seeing MLs comment and thinking 'must try that', as he described the exact scenario when it happens, and never did.

And kudos to Lee, even though we ignored him

[HPsauce]

Originally Posted by steamship

And kudos to Lee, even though we ignored him

Kudos indeed, though I didn't ignore him, I was distracted. Mainly because a few days later I had this:

Originally Posted by HPsauce

Worrying development this morning - limp mode!

Which I then didn't get fixed until fairly recently (November - 9 months later!), so I just assumed (incorrectly I think) that the F125 was the only problem.

Then in December MJ referred back to my initial problem. And moltuae mentioned the brake pedal switch. You then weighed in with your issues and the brake switch problem became clearer due to both you and MJ. Then my symptoms reappeared and, as they say, the rest is history.

Let's hope it really is history. And an experience that can help others.

PS Sean, good to see you'll be at the June meet.