My 3.6 won't idle and dies, idles and dies, repeat until Warm.

[A 911 Dream]

I know there are a lot of 3.6s installed across this thread.

My new to me 1992 C4 has gone through an extensive engine out re-fresh but it continues to stall at cold start, erratic idle, dies, repeats until warm and then drives great.

Initially the original ISV was cleaned, re-installed, but didn't resolve the issue.

I bought a new ISV (Lowe Automobil), installed it and it apparently "cured" the issue but it became re-infected. I didn't have the car at this time so I can't confirm how well it ran for or how long?

I have scoured the Forum, received some feedback and compiled the below list.

Any other suggestions? As mentioned, the car stalls at start-up and continues to stall out until warm. Please feel free to let me know if any of the below should be removed from consideration given that it eventually warms up, idles and drives normally.

1. O2 sensor?
2. ISV properly installed? Backwards?
3. DME relay
4. Engine Temperature Sensor
5. Vacuum leak?
6. Idle microswitch set-up / throttle linkage
7. Cylinder head temperature sensor

Thanks,
Chris

[uwanna]

Had exactly the same symptoms you have. Read this post, it fixed my problem but
some weeks later problem resurfaced. Then repeated the fix, no problems since.
964 hard/no start problem

[RedCoupe]

Continuing on the electrical side, a few years back my 964 started running erratically during warm up and stalling whether hot or cold. After a lot of testing and replacing ignition parts, I found that the main battery negative cable had approximately 700 ohms resistance instead of zero. A new battery ground cable solved all of the problems.

[A 911 Dream]

2 great suggestions. Thanks guys.

UWANNA, before you diagnosed and corrected the issue, did your car eventually warm-up and start to run properly?

I certainly will give this a go - can't see any downside to your proposed solution and it certainly is way cheaper than starting to order random parts.

Thanks,
Chris

[uwanna]

Originally Posted by A 911 Dream

2 great suggestions. Thanks guys.

UWANNA, before you diagnosed and corrected the issue, did your car eventually warm-up and start to run properly?

I certainly will give this a go - can't see any downside to your proposed solution and it certainly is way cheaper than starting to order random parts.

Thanks,
Chris

Yes Chris, my symptoms were precisely the same as yours. Try the fix and good luck!
Grant

[uwanna]

Chris,
Any update on your problem? Did you try my suggestions?

[A 911 Dream]

Thanks Uwanna.

The 964 is back in the shop. In addition to the cold start issue, there was a "dragging" sound from the steering wheel.

I'll definitely update this post if the issue is resolved with your suggested fix.

Thanks again.
Chris

[A 911 Dream]

So, we’re chunking through the list and still no resolution.

Uwanna, unfortunately your DME solution didn’t work.

Going to look for ground issues next.

Anyone else had a similar issue that was resolved with new ignition coils? Or a replacement DME relay? I want to try to avoid dart board new part purchases, if possible.

But, open to any/all suggestions.

Thanks
Chris