I just installed a new GM crate motor using all my TPI stuff and now my car revs at 2500 RPM's. I checked for vaccum leaks and do not see any. I also set the TPSsensor. I even tried turning the idle screw until the butterflys close enough to hit the wall of the throttle body and it still revs high. what could this be. What does a motor rely on for idle speed on start up. Does the motor need the TPS and IAC sensors when you first start the motor and let it run for a few minutes? what is causing my motor to run so high for. please help I need to set my timing and fuel pressure and cant do it until i get the motor to idle right first.

 

I'd guess it could be a vacuum leak or advanced timing...not sure if you could get the timing to take it to 2500 though.

Is the IAC fully extended to close off the passage?

 

how can i check to see if the IAC is opened or not

 

Well, you can extend it manually, and leave it unplugged.

Or you can jump the A and B pins with the key on (look for the procedue to set min idle in the Tech Articles on the main page), but if it is electrically not working, this won't do squat for you.

 

Oh, I should mention you'll need to remove the IAC to manually extend it, then reinsert it. Make sure you don't go more than needed, no use tighteniung it back up with the pintle binding against it's seat.