90 GSX
15+ Year Contributor
- 322
- 2
- Jun 24, 2004
-
Fremont,
California
When I was installing my big16g a few days ago my friend turned the key to the ignition on position to move my steering wheel to get some extra room down there. I didn't know this at the time.... when we started connected the lines to the turbo, I think he went to plug in the MAF or some other connector in the area and right when he did it, I heard a couple noises and the legendary buzz sound come from the ISC. Since then, my idle has not been right. Some peolpe just don't use common sense I guess... Anyway, I didn't think anything of it, I just turned the key off and finished installing.
It almost seems like the ISC is not doing anything. When the car is cold it usually idles around 1300-1500. Now it's more like 1800-2000, like the ISC can't compensate for the extra FIAV air. When I am crusing and throw it in neutral to come to stop, the idle is low (it should stay up while I am slowing down until I stop, then it should go back to 750). It hangs out around 700 stumbling but not dying, then when I finally come to a complete stop, the idle rises to about 900-1000. On occasion I have seen the idle fluctuate slowly but it's usually a steady idle, at the wrong speed.
Testing the ISC coils was the first thing I did. All of them register fine (~35 ohms warm).
The ECU is freshly rebuilt and has ran well for 4 or 5 months now.
When the car is idling high, my logger says the ISC is at 14% and it doesn't change or try to compensate.
Other than this problem the car runs perfect and pulls hard.
I will test the other sensors on the TB, but the IPS and TPS were both adjusted perfectly.
WHAT GIVES?????
It almost seems like the ISC is not doing anything. When the car is cold it usually idles around 1300-1500. Now it's more like 1800-2000, like the ISC can't compensate for the extra FIAV air. When I am crusing and throw it in neutral to come to stop, the idle is low (it should stay up while I am slowing down until I stop, then it should go back to 750). It hangs out around 700 stumbling but not dying, then when I finally come to a complete stop, the idle rises to about 900-1000. On occasion I have seen the idle fluctuate slowly but it's usually a steady idle, at the wrong speed.
Testing the ISC coils was the first thing I did. All of them register fine (~35 ohms warm).
The ECU is freshly rebuilt and has ran well for 4 or 5 months now.
When the car is idling high, my logger says the ISC is at 14% and it doesn't change or try to compensate.
Other than this problem the car runs perfect and pulls hard.
I will test the other sensors on the TB, but the IPS and TPS were both adjusted perfectly.
WHAT GIVES?????
