So i got a Peter Farrel intercooler for my 93. Heres the mod list:

Streetport, Downpipe, High flow cat, catback, M2 Air Box, Power FC

And i just put on the PF IC today. Hooked it all up and started it. Engine revved to 7000 and held. Shut it down, check everything over, find a spot that didnt sit right so i fix that up. Start it and it revs to like 4 grand, holds for a second, drops to 1000 then fluxuates to 2500 and back. Well i leave it running and start poking around the engine bay and after a couple minutes i notice it isnt revving as high. It was actually getting closer and closer to a normal idle. A minute or two later it was idling find. Revved fine, drove fine.

So my question, why did it just start working and do you think it is going to work tomorrow morning?

 

The PFS intercooler would have nothing to do with your fluctuating idle. Maybe you accidentally bumped into a hose or something...

 

you dont think a leaking intercooler pipe would cause an idle like that?

 

anyone else?

 

No, it wouldn't. I can't explain your situation though, it is wierd that it fixed itself.

 

yea, i didnt even mess with anything to get it fixed

 

Maybe it was something with the PFC...increased airflow maybe tricked it at first (at idle) and it needed to relearn the idle airflow? Just a wild guess

 

I agree that it was the PFC relearning the idle. But it's strange that it would rev to 7K at idle in the first place, even if you leave an intake pipe completely open, I've never seen it idle that high. Normally an IC change wouldn't affect idle unless it's leaking somewhere. I'd test the IC and couplers for leaks, otherwise if it keeps working don't sweat it.

 

the pfc relearning was my first thought also, i just didnt know if that was a possibility. The car held up fine today, held 12 lbs of boost just fine so i think its good to go

 

The idle control on the car can't get the RPMs THAT high. Plain and simple, your throttle body is stuck open. Most likely there was a rag or packing material in the intercooler that got sucked into the throttle body. Pull the throttle body elbow and do a thorough investigation.

Guys, if you buy a used intercooler, you REALLY need to make sure it's clean and proper before installing! I've seen someone pull a used IC out and toss it on the car, then the car was idling weird. Pulled the TB elbow off, there was a shop rag and METAL SHAVINGS in there. Fortunately it didn't seem to hurt the motor, but you never know what the IC's previous life was like.

Dale

 

when i got the ic the pipes on both ends were duct taped shut, removed that and dumped it and nothing came out but i guess ill pull the elbow and make sure.