I seemed to have fixed all but one problem with my SC. When the engine gets to a specific temperature, the car will begin surging at idle. It will rev up to about 1800 rpm and then rev back down to 200 rpm, nearly stalling. This only happens at idle though. Any ideas?

Thanks,
Alex

 

I'm interested in this thread..mine does the same thing. When it is dead cold it's fine. When it is super warmed up it's fine...in between it surges up then dies...up then dies (if I tweaked the idle position it would probably idle at 200 or so like yours..cause if i just rest my foot on the accelerator alittle bit it will idle low). Weird thing is after about 30 minutes of straight driving it's fine.

Also Thanks!

Jim

 

My early CIS car used to surge until I had the mixture properly adjusted.

Also, look for vacuum leaks by spraying a bit of WD-40 around the vacuum hoses, air box, and air lines (be careful to not use too much or you may start a fire!).

 

Hi:

Harry offered some sound advice as vacuum leaks from the intake manifold rubber hoses and injector O-rings will cause rough running. I use a can of carb cleaner to spray a bit around all these junctures and if the idle speeds up momentarily, you've found the problem.

I would also find out what your CO is as rich or lean conditions will cause surging. The fuel filter must be clean and if its not been changed in 10K, its time for replacement.

Also,....Warm-up Regulators do not last forever and since those controls fuel pressures, that should also be thoroughly checked out.

 

82911SC, my 83SC did the same thing. I took it to TRE in North Hollywood and they changed the injector seals and cleaned them. They (Tyson) also set the mixture and my problem was solved. I saw that you live in Malibu, not that far from TRE.....

Good luck, David

 

Alex: You're right down the street from Marc At Red Line (720 Colorado Ave, Santa Monica). Call him, your problem sounds like an easy fix, as Steve suggested. (310) 450-7414. FYI: Your car will stall just below the lowest engine speed (600 rpm, not 200) reflected on the tach.
Pete

 

Correction! - I think that I mis-spoke regarding the tach & stall speed! Too many cars, too little time... Your car's tach probably reads all the way down...
Pete

 

My '85 did this 'surging idle' but it seems to have gone away on its own (hasn't happened for a couple years - knock on wood). It only happened every loooong once in a while, usually after sustained freeway driving.

ken

 

I suggest checking Fuel Frequency Valve or Relay. I may be wrong and I am new to these cars, but, they cleaned up my idle and hesitation problems. New Rotor and Distributor cap helps. I had a lot of moisture in mine. Fuel Injection cleaner too. Please don't beat me up over a fix for me. Newbe!

My 2 cents worth.