ISC pintle movement?

[forcefed86]

Seems I've been fighting this idle surge for a while now. TB rebuilt. FIAV blocked. New o-ring on BISS. Pressure tested entire system. No change.

I can watch the ISC count on my datalogger and it seems to be working at higher rpm. But at idle it doesn't change. I can even adjust the biss screw while idling and the ISC valve never changes to try and compensate. So either the ISC has a problem or my ECU drivers are on the fritz!

I unplugged the neg bat term. Removed the ISC. Key in the on position. Connected the neg term on the bat. The pintle retracts until it hits it's stop and then just clicks for a second or so. It never drives in. Is this normal? Shouldn't it "smoothly drive in and out" per the vfaq?

Think this sounds like drivers in the ECU crapping out or ISC?

Thanks!

 

[yokotabrat]

If you can actually see the ISC pintle moving when you reconnect the battery terminals, that means the drivers are likely good, as is the ISC. It isn't a smooth movement. On older ISCs it's a pretty loud clacking.

Have you verified that your closed throttle switch (idle switch) is operating properly? A lot of times the switch either gets gunked up internally and doesn't make contact electrically, or the ground strap and brace are missing, so the switch doesn't get a good ground connection.

 

[rstchris]

The ISC will still function without the idle switch, it is only for pulling fuel over 14-1500rpm on closed throttle. My ISC was being OWNED by the stiff spring in it and was locked up. I had to clean all the parts and put a softer spring in it. Now it works perfect. If you don't have the servicable one get on from ebay for $10. It's the one with 3 screws on the front.

 

[forcefed86]

Yes I tested the idle switch.

I can give the softer spring a try. How soft did you go?

$10? Cheapest I found was 50. Could U shoot me a link?


thanks guys!