Re: I tried the basics, need idle help. (archive)

There is a screw in the ICV(Idle control valve) Turn this screw and it will change the RPM the motor idles at. If this doesn't help, then adjust the stop on the throttle body and that will also change the idle. As for the serging, I have found that that generally means that the ICV is faulty, but yousay it is good. Maybe try cleaning it out.
Rob A
M535i SIG Technical Advisor
www.M535i.web.com

My '84 633 will not tightly regulate the engine speed after warm up. Speed cycles between 1000 and 1200 RPM. No drivability issues. I am certain the problem is in the idle system because the problem begins after warm up and as soon as the throttle switch opens, the engine speed is steady. I just rebuilt an engine and put it in. The old engine had no idle problems. No vacuum leaks are evident. O2 Sensor appears OK. Idle valve buzzes and mA is within rang. Screw setting controls solenoid current, but not idle speed or oscillation speed. All voltage and resistance measurements were as suggested per Bentley's manual. Throttle adjustments are as per Bentley's as well. Cleaned idle valve and checked solenoid valve operation-OK. What's left? Any insight would be appreciated.

There is an idle control module in the glove box near the ECU. It is probably black or green. There was a recall. However, the control module is probably OK since it worked prior to the engine swap.
If the car is running too lean then the idle will jump around. Check for vacuum leaks.
On my car, the idle was jumping around because it was running too lean and when I pulled the cover off of the Airflow Meter I could see that the little needle was jumping back and forth when the car was supposed to be at idle. I lessened the spring tension in the AFM a bit and adjusted the idle air bypass. This made the idle smoother and the little needle in the AFM settled to a steady position at idle.
Check out this link: http://www.mesaperformance.com/faqs/idle.html
If it is not a vacuum leak, a lean-running condition or a bad idle control module then you may have incorrect valve gap settings.

A question for you guys...
What is the correct (factory) idle setting for these cars:
3.0
633/635
M635

My old 1984 633Csi was quite happy around 900. My M635 seems to idle much smoother around 1200, but that seems a little fast.

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Re: I tried the basics, need idle help. Rob Anderson 19:18 12/11/2000 (0)

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