Cold idle issue 89 3.2 Carrera

[thepenguin99]

I recently purchased this car and drove it home 1900 miles. All in all it performed well on the drive home. That said, it seems to have an issue at idle while cold. It will idle but if you rev it and let off the accelerator it will die. It also seems to rev more sluggishly than when hot. Not sure if that is a symptom or normal. I googled the dieing issue and thought there was a good chance the ICV was bad. The part was reasonably cheap on Amazon and easy to get to so I purchased it. No change after install. Something I did notice after it died today is that the exhaust has a fairly strong gas smell to it. It would seem to be getting too much fuel. Any help would be appreciated.

[dshepp806]

That ICV can be cleaned,..usually with good results. Sometimes not,...sounds like you've already changed that out.

I'd look into the idle setting, especially the mix settings. Get her measured to see that she's within specs as to mix,..(first things first).

BEST!

Doyle

[Justin@Athens]

The question is why can't the ECU find the correct fuel/air mixture. The idle is not "adjustable" per say in motronic, or at least it should not need to be adjusted. The fact that you smell unburnt fuel in the exhaust indicates a rich condition when cold. I'd install a new o2 sensor before doing anything else.

Even before that however I would check to see that the idle microswitch is being triggered when the throttle linkage comes to full rest. You should be able to hear it/feel it if you manually squeeze and then release the throttle in the engine bay.

Also check for vacuum leaks. The ICV can compensate for vacuum leaks, but will only do so when the idle microswitch is functioning properly.

[thepenguin99]

I have removed the oil cap and it makes the engine run rough but not stall. I have read that this is a pretty decent indication I don't have serious vacuum leaks but not sure how true that is. The PO mentioned replacing the O2 sensor within the last year but that doesn't mean much really. I will check the microswitch next then probably buy a exhaust gas tester if the microswitch is working.

[VMAX1]

check out this thread....Alternative Fuel Injectors
My 3.2 had a good cold idle and rpm's would drop in a few. That is when my idle would be choppy. I could not pass up this deal. Hot cranks would be a bit longer on the key, not any more. Maybe, you have injectors that are leaking fuel when shut down. You may already have one, but a Bentley is a good tool to have, but this forum is the best tool a Porsche owner could have!

[DCinVA]

Justin's advise is spot on.

In addition, get a bottle or two of Techron fuel system cleaner and add it to you next tank of fuel. 20+ year old fuel injectors can be a bit finicky, and techron can help them to operate as designed.

[inthedoghouse]

I've run a few bottles of sea foam through mine over time and it seems to help smooth things out a bit.

[stlrj]

Originally Posted by thepenguin99

It would seem to be getting too much fuel. Any help would be appreciated.

Pictures of the engine, close ups, would be helpful.