- High Idle on Cold Start
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High Idle on Cold Start
My '87 325iC recently started idling high after a cold start. It will idle high for 8-10 seconds and then settle down. If I push the accelerator and release the clutch, drive a 1/4 mike to the stop sign and clutch in, the same thing happens. This goes on for 1-2 minutes then it settles out and drives normal.
I'd suspect a vacuum leak except I'd think it would continue throughout idle and wouldn't be limited to just cold start.
This car has a stock engine other than a Comforti chip. The chip has been in for years and this is a relatively recent change in idle. A BMW mechanic friend suggested I clean the throttle body and plate with carb cleaner. Done. No change.
Suggestions? Spark plugs, O2 sensor, vacuum leak, what?
Thanks in advance for any help.
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Idle control valve,maybe?
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Maybe. I hadn't thought of that. Would be an expensive guess!! I may have to try it if I can't come up with something else.
Any way to test it? Ohm meter or something?
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Just reporting back. I cleaned the ICV with brake cleaner and then let it sit a few days to dry out while I waited on some brake parts, etc. from BAVauto.com.
Net, it appears to have fixed the problem!!! So, thanks for the tip.
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here's a weird suggestion. How tight is the throttle cable to the throttle body? I've seen a few cars where the cable is just too tight. there should be a bit of slack at idle.
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Problem is back. I'll check the cable.
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Hate bump old threads, but looking for a solution here. I have the exact same problem and a, having difficulty finding a fix. Haven’t thrown any parts at it, but curious if anyone has advice on this 12 years later. Thanks.
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how high is the cold start idle?
No e30s again.
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It will cold start idle 1.8k to 2.0k. I don’t think I see it go above 2k. It will start and idle pretty well until I give it gas. Generally it’s once I load the engine and travel a little bit in first or second then when I come to a stop it will idle at 1-1.5k and quickly creep up to 2k. This happens until it’s warm.
Example, once im on the highway for a bit then come off the highway it will idle just fine.
No problem during the winter cold starts.
Now as these cars are so old, I’m hesitant to include to much unnecessary information that may muddy the waters. I have checked a good amount of items and troubleshooted a lot of items and will chime in with those when/if necessary.
Last edited by Wrench Turner; 04-19-2019 at 08:17 AM.
Reason: Info
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First thing to do when checking high or erratic idles is to check to vacuum leaks. A lot of times thats all it is. When the car heats up the hoses expand and wherever it's leaking from will seal up. Check the hose going from the valve cover to the throttle body, when that one leaks it really messes things up. The valve cover gasket leaking could also cause some issues with vacuum as that hose mentioned earlier will be sucking in air from the valve cover.
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