1992 E36 325i - Rough idle at all times. Hesitates when cold.
I've got an issue with erratic idle on my E36 325i Coupé Non-VANOS.
It's not really the classic 400-1000 rpm surge, it's just erratic, sounds as if cams are swapped.
Tried disconnecting O2 sensor. No go.
Tried disconnecting TPS sensor. No go.
Tried disconnecting water temperature sensor (blue). No go.
Tried disconnecting MAF. No go.
Tried disconnecting IAT sensor. No go.
Tried another ECU. No go.
Tried another MAF. No go.
Fitted new rubber boot. No go.
Haven't checked the ICV as it's not surging as much as just being erratic.
It idles poorly at all times, when cold it surges a bit from 7-800 rpm in "jumps", and the engine hesitates while driving. Seems "nervous" in its running. After approx. 4 miles, the hesitation disappears as fog to the sun (litterally from one second to another!), and all is well - except for the rough idle as told above.
If I start the engine when it's hot, and drive, the hesitation is not present. It's only when driving for the first few miles after a cold start in the morning.
SOLVED!!!!!! CPS was the culprit.
Last edited by puttitat; 09-27-2011 at 08:23 AM.