Erratic throttle response when cold

[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]

Originally Posted by 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.

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:




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]

Originally Posted by HPsauce

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...7/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!

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?

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?