HELP !! cant get IAC #'s down for the life of me..

[AsphaltAnihil8r]

Ok the car is Running like crap,idle surging up and down from 800-950rpm,,IAC is 127, temp is 200°

What I did was to take the TB and Dog house off my GN that is running fine,,and put it on the Bad running Turbo T,that did not help, the IAC is still sky high,,now the Gn ran fine with the same parts that I just swapped over to the Turbo T,but its still high,,How do I check the signal going to the IAC,,there are 4 wires and I have a Fluke multimeter,Scanmaster2.0,,please guide me

At this piont I am thinking it is the signal ,,
could it be a Vacuum leak causing the IAC to never come down?

Dennis

 

[TurboTR]

Well a vac leak would drive them lower, not higher. If the engine and all was healthy then it sounds like maybe you just need to re-adjust the throttle blade setting, open slightly more in this case, and then reset the TPS of course. Opening the throttle blade will tend to drive the IAC counts lower and vice versa. Don't know why the rest of the stuff is crappy though (surge, 200 deg, etc). Can't get a good final setting until the rest of the stuff is sound...

Do you have a PCV valve with open crankcase breathers? That can really throw things off at idle since the valve acts like a big leak in that case. Sorry, don't know what has been posted anywhere else about your problem.

The IAC is a stepper motor that has pulsed signals on the 2 pairs of lines going to it.

TurboTR

 

[AsphaltAnihil8r]

here's an update....

I took the TB and Dog house of the T which idles like crap,has IAC counts of 128 with the coolant over 190° AND put it on the GN that was running perfect...

And it still runs perfect

The Turbo T still runs like crap with IAC of 127 ,and that is with the TB and dog house from the GN which was running perfect

So I know that my problem is not the IAC Valve itself or the TB

What could cause the IAC to bee so high

Dennis