Unstable idle on a 16V. Where to look?
My wife`s 87 190e 16V has issues. Starts immediately when cold and idles fine while warming up.
(I believe the mixture specs are different than what Stevebfl describes on the 300e as when I turn the mixture screw clockwise to richen, the duty cycle number increases (?). I currently have it set at 55% and am seeing a zero to negative two millamps at the EHA which I think would correspond with a slightly rich mixture (does this make sense?)
Anyways after I adjust it when its hot, it idles at a nice steady 900 rpm. Go for a drive around the block and return and its idling at 1200 rpm. Turn it off and restart, and it almost always idles near 900 rpm. Drive around the block and return....back to 1200 rpm? It also has some moments when you come to a stop where it nearly stalls or stalls. But once it starts to idle at 1200 rpm, it won`t stall which is understandable.
Any ideas? The decell switch is ok, throttle position swith is making contacts a idle and full, air idle valve is new, OVP is fine since I am seeing ma at the EHA. NO vacuum leaks. valves adjusted. Air flow position sensor appears to be within spec. with a nice linear increase to approximately 5v. I know these have been problems with these car and are prone to causing high idles. Should I focus my attention there? What else could cause the idle to change???
Thoughts? Condolences? Prayers?