'83 380 SL 296k miles. starts fine, idle at 650. When the temp reaches about 85C the idle Sometimes jumps to either 1100 or 1400 rpm. Again sometimes the idle stays high for only about 1 min then is normal. At other times it stays high.

When idle is normal the voltage at the idle solenoid is 14.0v. When the idle is high the voltage is .2v. Recently replaced the temp switch. The idle controller and solenoid were replaced in 1994 (about 30k miles ago). Checked the idle speed according to the shop manual with the throttle position switch disconnected and temp switch by the oil filter disconnected. Tested OK.

I have attempted to test the output voltage of the idle controller but each time I turn the engine off the idle is OK on restart!

Fast idle is not affected by AC on or off. Car runs fine otherwise. All rubber vac parts and idle circuit parts were replaced in 1994.

?

Bill Dormandy
Dorvbell@compuserve.com