barza21
15+ Year Contributor
- 106
- 31
- Oct 11, 2006
-
Fairbanks,
Alaska
Hello,
The car in question is a 1991 Eagle talon TSI AWD (6bolt). I just rebuilt this engine about 100 miles ago. Here is the issue that I am having: The car won't idle correctly. It surges. I have done some research and have gotten some interesting results back from the testing that I completed. I have narrowed it down to being an electrical problem (or so I think). I have taken care of the boost leaks. The TPS is adjusted properly and so is the idle switch. The TB is properly grounded. I did a basic test of the IAC. I took it out of the IM and had somebody turn the ignition on. When I did this the IAC simply rattled. It didn't move smoothly how it's supposed to. I bought a new one, connected it to the harness and the same results occurred. I swapped the original ECU with a spare one that I had, and it still does the same thing. I checked the wiring from the ECU to the IAC connector, they are ok (good continuity). I checked the power wires to the IAC connector, they are ok(good continuity). I checked for voltage at the IAC connector (pins 2 & 5) , 12v were present there). What are the odds of another bad IAC? The resistance of the coils are way within specs (39.2-39.6 ohms on all coils). I have opened the ECU and inspected for burned ISC drivers and I cannot see any sign of a burn or damage that has occurred. Are there any other suggestions as to why the IAC is not testing properly when I hold it in my hand and it connected to the harness? When the car is on and idling, when I disconnect the idle switch, it does nothing for the idle. It doesn't stabilize it. It keeps surging. I checked the switch and it checked ok. Any other suggestions as to what to check? What am I missing?
Thank you for your time.
Oscar
The car in question is a 1991 Eagle talon TSI AWD (6bolt). I just rebuilt this engine about 100 miles ago. Here is the issue that I am having: The car won't idle correctly. It surges. I have done some research and have gotten some interesting results back from the testing that I completed. I have narrowed it down to being an electrical problem (or so I think). I have taken care of the boost leaks. The TPS is adjusted properly and so is the idle switch. The TB is properly grounded. I did a basic test of the IAC. I took it out of the IM and had somebody turn the ignition on. When I did this the IAC simply rattled. It didn't move smoothly how it's supposed to. I bought a new one, connected it to the harness and the same results occurred. I swapped the original ECU with a spare one that I had, and it still does the same thing. I checked the wiring from the ECU to the IAC connector, they are ok (good continuity). I checked the power wires to the IAC connector, they are ok(good continuity). I checked for voltage at the IAC connector (pins 2 & 5) , 12v were present there). What are the odds of another bad IAC? The resistance of the coils are way within specs (39.2-39.6 ohms on all coils). I have opened the ECU and inspected for burned ISC drivers and I cannot see any sign of a burn or damage that has occurred. Are there any other suggestions as to why the IAC is not testing properly when I hold it in my hand and it connected to the harness? When the car is on and idling, when I disconnect the idle switch, it does nothing for the idle. It doesn't stabilize it. It keeps surging. I checked the switch and it checked ok. Any other suggestions as to what to check? What am I missing?
Thank you for your time.
Oscar