Talon runs rough, ECU is speachless

[GriffLaserRS]

My 90 Talon TSi FWD runs horrible. The car runs fine under load but seldom idles right. The car spits and sputters if the throttle isint open atleast 1/3. Idles anywhere from 2000-500 rpm. What could cause this? Throttle body was replaced by the previous owner. The car picks up idle when I turn on accesories but still will barely run. I figured if the throttle body and sensors were to blame i would at least get a check engine light?

 

[Turbo Talon DL]

Ok, im just gonna take a couple swings at it. Is your idle switch next to the ISC hooked up? That switch tells the ecu to run in idle mode with closed throttle. Next, are you running your coolant lines into the bottom of the T-body? If you dont run those, the fast idle air valve will never close. Have you checked for boost/vac leaks? If that thottle body has bad shaft seals, you will leak, more than what you would think. Try some of those things if you havent already. Im sure somebody who knows more than lil' ol me will help you out.

 

[GriffLaserRS]

The ISC was junk. I replaced the whole throttle body for $2o from a junkyard. It was 20 degrees out today and was a pain but I did it. It ran alot better untill the idle screw which i hadent touched flew out the top. luckily i had the old TB shotgun. The car still spits and sputters. No more leaks. How do you test the ECU? I tried using a LED but got nothing. Better but not quite right.

 

[GTM]

...
It ran alot better untill the idle screw which i hadent touched flew out the top. luckily i had the old TB shotgun. The car still spits and sputters. No more leaks. How do you test the ECU? I tried using a LED but got nothing. Better but not quite right.

How did you determine where to set the biss screw?

Cheers,
GTM

 

[steve]

How do you test the ECU? I tried using a LED but got nothing.

http://www.ecanfix.com/~mdhamilton/errorcodes.html

If you use an LED it has to be a 12v LED (with internal current limiting resistor) or a regular LED with the correct series resistor and oriented correctly. Pin one will pulse at +12 with pin 12 being ground. I use a 12v piezo buzzer from Radio Shack (273-059) instead.

http://www.radioshack.com/product.a..._011_002_003_000&product_id=273-059&hp=search

Steve

 

[GriffLaserRS]

I tested once again and recieved no response. Dug through the dash pulled the ecu and it looks great. My sense of smell is poor but it definatly smells like fish!!!!

 

[steve]

I tested once again and recieved no response. Dug through the dash pulled the ecu and it looks great. My sense of smell is poor but it definatly smells like fish!!!!

It's interesting that your ECU runs the car, even if it does it poorly but you don't get the heartbeat from the diag connector. If it smells funny then the caps have leaked but it sounds like even thought you can see any leakage it's gotten to at least one other circuit. From what you describe your car doing it sounds like it might have damaged the ISC circuits and the communications.

Steve