300E Idle Speed

Hello,

My 1988 300E W124 has idle speed problem...when the car is cold, idle speed (when engaged in P or N), it's about 600-700 rpm (which is normal), however, when the car is warm, the idle becomes 1500 to 2000 rpm (when engaged in P or N)!!

My MB mechanic told me that the electronics part of the "air flow volume" sensor (the thing that looks like a diaphragm underneath the air filter element) is defective, however, the actual diaphragm is fine. He told me that I must replace the whole thing (the diaphragm with the electronics part) must be replaced, since they only come together, and the electronics part is not sold separately. The whole thing will cost CDN $700!!

I figure, if the electronics part is available separately, I would save quite a bit of money. Is the "electronics" part available separately? Does anybody have the part number to it?

Thanks very much.

Lee !
I have to tell you SORRY the air flow sensor is only come with air flow housing you can't
buy it separately have to pay big $$$ for it
hope is help.

The reason that you cant buy the sensor separate is that the adjustment is very critical to emission results & most shops don't have the equiptment to test the emission output.

Be sure that it is not the throttle switch that is faulty! Either way the fuel distributor has to come off.