92 Talon Idle Problem

[force_feed]

Whats up?

Ok, I have been working on a customers car, and I cannot for the life of me figure out what the problem is, so I'm looking to my fellow DSM'ers to help me out.

The car is a 92 Eagle Talon Tsi, and It idles around 2000 rpm's with a slight idle surge (it goes from 1900-2000 fairly quick).

The car has an ECU from an 90 gst, and I swapped the 2 wires at the ECU. I cleaned the throttle body, and replaced the gaskets. I checked the TPS sensor to make sure it was set right, and working. I've tried to ground out the ECU to adjust the BISS screw. When I do ground out the ECU, the idle DOES NOT GO DOWN!!!!

Funny thing is the ECU out of the 92 makes the car idle perfect, but wont rev past 3200. It starts to cut out and sputter while sitting in neutral. Sometimes with the 92 ECU, the car wont start. So I decided to switch out the 92 with a 90. It starts right up, and will rev to redline. The idle is way to high though, and has that slight surge.

Can anybody point me in the right direction?

Thanks
-Jonathan

 

[stevo911]

The 92 ECU is shot thats why it wont rev past 3200. Now theres a good chance the ISC motor is gone to that would cause the idling issue and also the issue with the BISS not lowering idle. Would not have noticed this on the blown ECU for the main fact that the driver for the ISC was more then likely blown by the broken ISC. If the ISC in a DSM is broke and left on the car it will in turn blow the ISC drivers damaging the ECU and making it not able to rev.

 

[force_feed]

I know the 92 ECU is bad. I just thought it was funny that the car would idle perfect with the 92 ECu vs. the 90 ECU.

I have another TB I'm going to remove the ISC from, and give it a try.