Almost embarrassed to report how easy it was to deal with the engine idle speed racing after replacing distributor cap & wires.......Here's the original post:


My daughter's '82 240DL continues to amaze us with it's antics. Found a bad plug wire several days ago & replaced
it....got the car going fine again. Today I pre-empted and replaced wires with new, also new rotor and new cap. Engine
races like gangbusters--had to unplug the IAC valve to tame it. Adjusted idle screw at throttle plate to get steady
normal idle, adjusted TPS to click with first movement of throttle plate. Plugged in IAC & ROAR, off it goes....unplug
IAC and nice, tame idle. Seems if IAC was bad, nothing would change with it plugged in or unplugged. This car has
the Chrysler ignition and Kjet fuel system. What gives??

WELL, upon close inspection I found the block temperature sensor plug that's just behind the distributor to be dislodged. A little finger pressure on it made contact and Presto! the engine idle drops to normal.....let it go and idle races to high rpm again. The rubber boot was deteriorated and wasn't holding the plug in place anymore.....I managed to wire-tie it, but this still seems to be a bit wimpy. However, problem fixed. Thanks guys for your helpful responses earlier.

Regards,
John Perry