Rick86

I changed my PROM from stock '86 to a stock '89 PROM, because I converted to '89 fuel rails. My car is trying to idle at 450-500 RPM when its cold. I already have the throttle screw screwed all of the way out. My car will idle around 600 RPM when warm, but that is still too low. Do I need to change the Idle RPM in the Prom? Thanks

Morley

You need to follow the "minimum air" adjustment procedure first.

conv90

On my 90 (speed density) there is a table called : "Idle engine speed vs. temp".
You should change this table to allow the IAC to run accordingly.
I'm running 775 rpm from 80 C° deg to 152 C°.
Values under 80 C° are higer...800 rpm at 68 C, 825 at 56, 850 at 44, 900 at 32 ,......
-Beppe-

Rick86

Thanks I'll try to set the IAC again, but I already did it once, not that I did it right.