Re:Engine Idle Too High 325ES

["Phil Otis" <psotis@xxxxxxxx>]

Brad,

What you most likely did was to have inadvertently cleaned your Idle Control
Valve. This is a cylindrical device that plugs into the air manifold
somewhere after the air cleaner box but before the air mass sensor. It has a
connector on the back and a smaller hose coming out the side. This valve
controls idle speed by bypassing air. The circuitry works by "learning" the
valve's actions and results, so the valve should NEVER be cleaned.

That said, I cleaned mine because my idle was horrible. After a while, the
idle settled down - maybe the circuitry had a chance to relearn the "new"
valve action after it was cleaned. I still have occasional idle problems
that usually mysteriously resolve themselves. I have all new vacuum hoses,
reworked cold start valve, plugs & cables, distributor cap, etc. The only
thing I haven't replaced is the ICV.

It's also remotely possible that by getting cleaner into this valve, the
idle control circuit, located in your glovebox, may have become toasted.
There are updated replacements for this circuit, which is prone to failure
anyway, especially on a car with your age.

best,
Phil
1986 535i


>>Well looks like I screwed up. Cleaned the mass airflow sensor and throttle
body with carb cleaner and replaced the rubber bellows that connects the two
and now the idle is way too high. I wonder if I toasted the mass airflow
sensor. Car is an 86 325ES. Can't find any loose connections or vacuum
leaks. Idle was fine until I tried to do this PM.
Suggestions appreciated
Brad Purvis<<

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