Yet another idle isuue.

[Drifte]

Ok, before any bashing begins, give me a chance, i dont have the free time to check everything.

allrighty, soo. The car is a 94 talon es, converted to turbo with turbo bottom end. the idle, well it was fine. It has a 92 tsi ecu, and i have gone over all of the wiring. when i unhooked one safc wire, it idled perfect, then the surge came back. so i hooked it back up, and it idled perfect, then the surge came back. I just completely unplugged the safc to see what that would do...idle surge all the time. Randomly the car will idle perfectly at 750, sometimes lower, usually though very high and surging. I have very little throttle control when this is going on.

i have read a bunch of other peoples surge problems, and i know what i need to check, but i want to hear some opinions. I really think its just the computer, the only cel i have is a knock sensor...and theirs nothing wrong with any of that.

today though, i had the hood up, and unplugged the throttle temp sensor, the surge went away, but it idled at 1600.

the coolant lines no longer run through the tb on this car, the previous owner removed those. Could that be it?

I know you all ne more information, and some variables need removed, but that will be when i have the time.

opinions ????

 

[Drifte]

I followed the step by step directions from http://dsm.org/how-tos/tttt/tttt3.html. I think that was a very very helpfull tech guide.

i have no boost leakes, my CEL is only for the knock sensor.
EGR is blocked off. So i clean the tb, which was all ready very shiny, i pulled the ISC, and sprayed where it was with brake parts cleaner. The ISC itself was extremely dirty, so i cleaned that, and reinstalled it. didnt do anything, so i tested the pins. http://dmtalon.v8eaters.com/ISC.html
^ that was also veryvery helpfull.

resistance between all pins was perfect, except for 1-2.resistance was a staggering 220ohm!

i tested my spare ISC, but resistance was incorrect on all but one pin.


I will keep all updated on what happens next.


-colton

 

[Drifte]

forgot to throw in how this came to be.

fixed all wires on ecu. car ran perfect. out of no where the idle surge comes back. i pop the cover on the ecu an theirs black soot on the inside of the cover...

After some reading i see the ISC coils can short out ruining the ecu. Correct me if I'm wrong, because i have a chipped and socketed e-prom to put in and i dont want to fry that.

 

[Drifte]

Dianosis: ISC.

i pulled one off my other car and it fixed it right up. I do need to reset my BISS, but i foret how for now...but thats another day.

have any questions about your idle you can PM me.

later

_colton