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Old 07-11-2019, 02:59 PM   #1
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E30 318is M42 Warm Start Issues

I have a 1991 318is with the M42 engine. Cold start and idle have no problems after I fixed the vacuum leak and cleaned out the ICV.

My issue is my engine would struggle to stay idle after I restart it after driving. It would fire up normally, and RPM would begin to drop and stay struggling to stay idle for about 30 seconds before going back to normal.

I've asked my mechanic friend but he doesn't know what the issue is, and now every time I warm start it I have to let it run for a couple minutes before I start driving or else it'd stall out.

any ideas?

*this issue only happens when the engine is warm. at cold start i can just hop in, start the car, and go.
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Old 07-11-2019, 06:14 PM   #2
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I had this problem when I first got my 318is, there's this black connector in the engine harness (under the beauty cover on the firewall, it's literally a 1 pin plug) that I disconnected and it fixed it permanently.

I remember being waist deep in old M42club threads and read something about how that connector is only to be connected on Euro 318s or something like that.

The M42 is already out or else I'd include a pic, I might have one deep in my phone's camera roll if you need some visual!
91 318iS - aluminum M52B28 + ZF320 + 3.15 Torsen
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Old 07-11-2019, 08:16 PM   #3
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Sure, it's possible that it's the no O2 sensor plug that's plugged in, but it could easily be other items, and I'd suggest that OP search for hot or warm start threads here or on m42club so we don't have to run in circles guessing.
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Old 07-12-2019, 04:07 AM   #4
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definitely disconnect the black plug fastestbox mentioned if it's not already disconnected.
1991 318is ---230K - DD
1991 318i ---- 308K - retired

Originally Posted by RickSloan View Post
so if you didnt get it like that did you glue fuzzy oil to the entire thing?
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