MAC Posted May 23, 2007 Report Share Posted May 23, 2007 The Throttle Body Idle Speed Control Actuator is causing idle problems. I think I may have to replace it even though I took it apart and cleaned the points and greased moving parts. I used the PCM to overide the actuator and sure enough when I force the plunger down the idle speed decreases. However, the plunger is not staying in as the idle speed will become erratic and increase again. I think it's time to buy a new one? Link to comment Share on other sites More sharing options...
Ranger Posted May 23, 2007 Report Share Posted May 23, 2007 Did you adjust it correctly after reinstalling it? Link to comment Share on other sites More sharing options...
MAC Posted May 24, 2007 Author Report Share Posted May 24, 2007 Did you adjust it correctly after reinstalling it? I left the factory adjustment alone. I took it apart in February and all was fine until the last couple of weeks. So I tend to believe it's time to buy a new one. Link to comment Share on other sites More sharing options...
Ranger Posted May 24, 2007 Report Share Posted May 24, 2007 Might try adjusting it first. It's easy enough and might save you some money. Link to comment Share on other sites More sharing options...
MAC Posted May 25, 2007 Author Report Share Posted May 25, 2007 I had to disconnect the Speed Control Actuator. The rpms where getting out of control and it was to the point that I was having difficulty using the PCMs 'Overide' to control it. So I decided to override the Actuator to lower rpms while idling, then immediately shut down the engine and disconnet the Actuator harness. I checked the plunger while at idle and it was confused--meaning it was moving in and out and causing rpms to surge to 2-3K. Unless there is something else causing the problem it looks like it's time to buy a new one. Link to comment Share on other sites More sharing options...
Ranger Posted May 25, 2007 Report Share Posted May 25, 2007 I checked the plunger while at idle and it was confused--meaning it was moving in and out and causing rpms to surge to 2-3K. Sounds like it may be time for a new one, but I am not sure how it would react if it was out of adjustment so I'd do the procedure just to be sure. Link to comment Share on other sites More sharing options...
jackc Posted May 25, 2007 Report Share Posted May 25, 2007 Mac - I'm pretty sure you can command the pintle to retract with the Key on but the engine not running. Then unplug the ISC. I went through the failing ISC / wild idle thing with my car and a new ISC solved the problem. One other possibility may be that the TPS is loose or failing - causing faulty signals to the ISC. But if I were in your shoes I'd do a visual on the TPS then replace the ISC motor. Good luck. This stuff is no fun....... Link to comment Share on other sites More sharing options...
MAC Posted May 25, 2007 Author Report Share Posted May 25, 2007 I checked the plunger while at idle and it was confused--meaning it was moving in and out and causing rpms to surge to 2-3K. Sounds like it may be time for a new one, but I am not sure how it would react if it was out of adjustment so I'd do the procedure just to be sure. I did retract/manually adjust the plunger with a 10mm open-end, but the Actuator compensated by forcing the plunger out further. I also made sure the harness was clean and secure, to no avail. Link to comment Share on other sites More sharing options...
MAC Posted May 25, 2007 Author Report Share Posted May 25, 2007 Mac - I'm pretty sure you can command the pintle to retract with the Key on but the engine not running. Then unplug the ISC. I went through the failing ISC / wild idle thing with my car and a new ISC solved the problem. One other possibility may be that the TPS is loose or failing - causing faulty signals to the ISC. But if I were in your shoes I'd do a visual on the TPS then replace the ISC motor. Good luck. This stuff is no fun....... I take it that the Throttle Position Sensor (TPS) is part of the ISC? I did a visual inspection to see if I could spot anything out of the norm but all looked OK. It is possible to retract the pintle without starting. I only started because I wanted to see if I could get the pintle to retract and leave it where the engine would idle at normal RPMs. This is indeed no fun, especially when trying to come to a stop and the engine wants to go. Link to comment Share on other sites More sharing options...
jackc Posted May 25, 2007 Report Share Posted May 25, 2007 My TPS is mounted on the side of the throttle body. I think 94 is the same. It is separate from the ISC, but it plays a big role in the signals the computer sends to the ISC. That's why I suggest that a problem with it could result in screwy signals to the ISC. But if its plugged in and seems ok, then my money is on a bad ISC. The only way I've found to keep the ISC out of the game is to unplug it. I had a wild ride home one day too, courtesy of the ISC. Link to comment Share on other sites More sharing options...
Ranger Posted May 25, 2007 Report Share Posted May 25, 2007 Mac, as Jack said, the TPS is located on the side of the TB. It is inline with the throttle plate fulcrum. Link to comment Share on other sites More sharing options...
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