W202 2.3 Kompressor M111 High Idle (Fixed)


New Member
Jun 19, 2016
W202 230K 1996
Recently bought a Mercedes C Class 1996 230 Kompressor with a high idle and wanted to share my experience as I believe I have fixed it (long term/temporarily).

I had a constant high idle (around 1400rpm no matter what temperature), checked all vac pipes, air intake pipes, etc, even changed throttle body for a good working one and the return spring - still the same. No warning lights either.

Anyway I noticed that there was a bit of play/slop in the mechanism at the throttle body so that you could rock it slightly back and forth allowing the butterfly to open slightly, enough to give high idle.

Noticed further down where the throttle cable connects to some kind of linkage that there was a plastic roller held on by a clip i thought i may have been worn and allowing the whole thing to move up and open the butterfly.

Anyway took it all apart (2x10mm bolts to remove linkage from inlet manifold) and then built up the old plastic roller with electrical tape, razor bladed off the excess on one side and put it all back together making sure the roller moved freely and that there was little free play as possible.

Now idles at 800 rpm! Had to adjust the adjuster bar right down but so far so good!

Above picture was taken before the fix (noticeable butterfly throttle gap before stop which has now been eliminated)
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