Rough Idle, Stall
Hello all, Customer brought this vehicle to us with a concern of, it dies intermittently when coming to a stop.. tested for codes (none found in any module) distributor timing was off by about 15 degrees, I adjusted it with no improvement did an upper intake cleaning (with BG equipment and cleaners) with no improvement. if I turn the a/c on (making the cooling fans come on) it runs fine, but when I turn the a/c off it surges a couple times and dies. the same thing happens if I use a scan tool to turn the cooling fans on and off. so I replaced the cooling fans with no improvement.. what next? what can I test next?
Thanks in advance!!
pull iac and clean check to see if passages are blocked. see if throttle plate sticking or needs cleaning. Luck sometimes these old ones are a pain.
These have bad tps might check it out and see use a scope to graph it and check closed throttle switch
I second servicing the IAC,Then having the minimum idle air rate set as well as an idle re-learn. Those procedures require a factory scanner to complete successfully. They are problematic for aftermarket scanners. If you are not equipped I recommend that you do not attempt.
I've seen this model do exactly what you'e describing. An intermittent maf sensor will drop out long enough to stall the engine and not code. Can be verified with a data recorder or scope on the maf output. If the car does this regularly it will be easier to verify
What are the readings when idling.Like fuel trims and temp,tps position,etc.Those might help you better pinpoint your issue.
Optical dist. Check that is free of oil inside, those car that use that kind of distributor can give you the same problem you got,
Check the egr valve may be stuck open a bit since it only happens at idle.When you turn the ac on it increases the engine to off idle to compensate for the load of the ac.Just a thought