Hey guys, I know they've been hundreds of posts on this but there seem to be so many different things that could cause this problem. I'm taking my car to the mechanic yet again tomorrow, but now that I've discovered all these online forums I can finally give the mechanic some leads. He's a friend so it's been relatively cheap so far (labour-wise anyway).
Anyway, my issue is the standard tracking idle - anywhere between 900 - 2100 rpm's. It's a 2000 156 2.0 Selespeed. I've had the throttle body and MAF replaced before with no real effect ($$$!). I tried cleaning the butterfly valve (before reading that this shouldn't be done on selespeeds), but that had no effect either.
I did an ECU and throttle reset yesterday, which actually seemed to make it worse - after around 5 minutes of the car being on it will now track up to 2200 rpm's - seem to hit some sort of defined barrier - and drop back down the 900, rinse & repeat... So anyway, I'm trying to compile a list of things for the mechanic to check out, please let me know if I'm missed anything!
The list (in no particular order):
1. Check/clean the idle actuator
2. Check/Clean the air filter
3. Check the Oil vapour separator valve (specifically the sprung valve in the breather pipe which connects the cam-cover to the inlet manifold)
4. Check for any loose seals on the air intake pipe
5. Check the contacts to the ECU for moisture
6. Check the stepper motor
7. Check the throttle potentiometer (what is this exactly?)
8. Check the Exciter wire connected to the the alternator.
I also wondered if the fact that I've been driving without an undertray for around a year may have something to do with the problem (as far as I can recall the problem started only after it fell off, though this could have been many months after).
I really love this car, but the constant revving makes it such an
Oh, and one more thing. It actually used to idle (at the start of the problem) between 600 and 1500 rpm's, occasionally stalling. I had another mechanic look at it and he said he adjusted the idle. Any idea what he would have done? After (and if) I get the idle tracking problem fixed, I'd like to get this set back to the original setting. Is it likely to be opening the butterfly valve slightly? I noticed that it did not close fully - is this normal?