during this past winter(downtime) i have installed many mods- pfc, 1300's,etc and blocked off everything i didn't need- emissions, sequential crap, and bypassed the throttle body coolant line. i've had my car running for over a month now and i have not been able to get it to idle smoothly under 2k rpm. i have checked isc resistance, wired back the wax rod thing halfway because of the throttlebody coolant line elimination, played with both idle adjustment screws for hours, checked for tension on throttle cable(cruise has also been eliminated), and tried changing pfc settings=no better. today i removed the isc solenoid installed a blockoff plate and viola! a nice 900 rpm idle. is it ok to be without this, i don't see why not, but i just want to make sure. will i have to make any adjustments on the pfc?
thanx for your time-garrett

 

I could not get the PFC to idle consistently on all three modes so I just unplugged the ISC, no problems but I have to make seasonal adjustments to the idle adj screw under the elbow. With my street port I have it leaned out at idle as far as possible without stalling, trying to keep the race plugs clean. It's not a perfect idle, it stumbles a bit and bobs around some like an aggressive cam, but it works consistently.

 

What is this ISC you speak of?

 

idle speed controller=isc. the only issue i have had is the occasional bobbing from 700- 900 rpm after the car is warm, but it does not do it all the time. i think i may try a isc off someone else's car sometime to see if mine was defective, although the resistance was within spec.

 

i'm having a similar problem. started it was just with AC on but now it does it all the time. hopefully i'll have a good ISC tomorrow to try. if you unplug the ISC you do lose idle control at the pfc (duh).

but you checked the ISC resistance turbogarrett? thats the only test the manual gives, so i'd hope if it was within spec that part would be working. else must be a pfc problem.

after i shut the car down i'll frequently get a buzzing noise from the area of the ISC so that may be it for me.

 

yes the resistance was within spec and i did have similiar buzzing sounds from the isc, so i am thinking something is mechanically wrong with my isc.

 

The buzzing noise is normal. Never heard with stock ECU but have noticed it on a few cars with PFC. I notice it with key in the ON position and motor not running.

Jack