Idling problems Z3 M Coupe. [Archive] - Bimmerfest - BMW Forums

: Idling problems Z3 M Coupe.

Matt O'DOnnell
07-11-2005, 05:53 AM
Hello to all!!!
I own a 99 Z3 M Coupe here in Dublin. I've owned the car for approx 3 months. Since, I've had the car, it has had idling issues. Some of the symptoms are:

1) After starting the car, the revs continue to rise quickly and won't stop until I hit the accelerator!
2) When at traffic lights, the cars revs will rise up and down from approx 600rpm to 1200.
3) And even when it doesn't do this, the car idles annoyingly high (at approx 1100 rpm). Sometimes, reving it hard fixes this and it settles back into 750 rpm.

Anyway, I have a warranty with the car and have brought it back to the specialist dealer where I purchased it twice already. The delaer tells me that the Vanos has been changed 3 times already (by a main dealer) so its unlikely that. Also I was on the website and they recommended that the o-rings be changed on the intake manifold. This was done (& improved things for a day or so) but it went back to normal soon afterwards.

I got other advice to clean the Lambda sensor and then grease the throttle cable. The specialist dealer has offered to do this again while he looks at the car (for a third time).
Also, I got advice to replace the potentiometer (but this costs approx 300 euro). Might do this as a last resort and its unsure if it will fix the problem. So here is the plan:

1) Change O-rings (DONE)
2) Clean / replace lambda sensor.
3) Grease Throttle cable.
4) Replace potentiometer.
5) Clean Idle valves (as they can become stuck)
6) Check / replace the throttle position sensor. Sensor Voltage can fluctuate, causing problems for the DME.

All these ideas came from the forum.
I will be giving this list to the mechanic next week when I give him the car.
Was just wondering if anyone else knew what else I could ask the mechanic to check? I was told this was a good forum for solutions!!!

Idling problem is driving me mad!!!! :bawling: :mad:

Thanking everyone in advance!!!