horrible idle....surprise
 

hey all, i have an 82 380sl. it has the haunted idle problem of 1500rpm in nuetral. i swapped out idle valves with a 82 380sel and it still sucked, just bought a new idle control module and that hasnt fixed it.....im gonna test the voltage at the idle valve later today. Is there any other item that could make this car do this??? thanks

There is a temp sensor in the intake manifold that gives the idle computer it's reference. If it's bad it could cause problems. I believe it's in the pass. side rear of the intake on that model..

If you do a search here you will find that the most common issues on W126 cars are the idle control valve or the over voltage protection relay fuse.

Not sure if your SL has similar systems but I would suspect they are quite similar.

Search here on OVP and see what you find.

Good luck.

Matt.

just tested voltage at the valve and it was 0.....so its gettin no juice whatsoever. im thinkin that relay is gonna be the one. thanks for your replies...

solenoid
 

test for current not voltage, solenoids operate on changes in current not voltage. Put the multimeter in current mode and put the multimeter in series with the solenoid (put one lead on one end of a wire going into the valve and another on the valve lead). with that said, you probably are not getting the right current to the solenoid which leads you to the temperature sensor, idle computer or I think but am not sure, the warmup regulator. Be careful making voltage measurements at the solenoid, I once accidentally did it and it shorted the solenoid and I think it can damage the idle computer. Mine was not damaged but the sound made wasnt good. Again, measure in series for current not voltage to avoid that.