89 420sel idle out-of-control

after 3 years, I finally got it running, but the idle is always at 1500 rpm or higher, I did some checking, auxilliary air valve is working(w/current will close). but after I start the engine there is no electric current event after 5-10 minutes engine running and warm-up. therefore there always extra air/fuel-enrichment.
Can you anybody tell me what sensor or relay control this valve ????
or any other suggestion ??
any help greatly appreciated
mark

Have you thought about testing the Idle Control Unit and Idle Control Valve?

I don't work on them, but my buddy just picked up his car from the MB mechanic. It had symptoms just like you are describing. Those are to the two items the mechanic mentioned.

Holla back when you get it resolved.