1G Idle Surge/Idle position switch?

[Chrisjones500]

Well I had the dreaded idle surge so I went through a couple of the steps to fix problem... Well I got into cleaning of the throttle body so I took it off cleaned it and reinstalled it and then hooked up all the conections....Except one..without knowing I forgot it...The idle position sensor?? for the ECU... I could be giving this one a wrong name but it is the 1 wire connector that fits right above the rotating spring for the throttle...Well when I started motor..PRESTO no idle surge, so I thought I was cool and started rechecking all the bolts and stuff then I noticed the plug unhooked so i plugged it back in .....IDLE SURGE!!! SO obviously this switch is bad in some way?? Maybe it is stuck wide open and when the throttle closes it doesn't know it so hence the revvvv, revvvv, revvvv that is so appealing.....So a long story longer...Is this switch replacable? Am I naming it correctly? is there a way to check it with a multimeter or something?? Will this harm my car if I leave it unplugged??

 

[CurtTSI]

The thing you are talking about is called the Idle Position Switch. To test it, check the electrical continunity between the body of the switch and the conector blade at the top of the switch. When the switch is fully open it should be non conductive. When closed it is conductive. Yes, it is replacable.

 

[steve]

It's not that the Idle Position Switch is bad, but that it's a key sensor that the ECU uses in deciding if you have an idle problem that results in idle surge.

With it disconnected the ECU doesn't think your throttle is closed and skips the tests to see if the idle speed is too high. The surging is caused by the ECU checking the idle speed and if it's too high, cutting fuel, the RPMs drop below the threshold and the ECU turns the fuel back on, your RPM's climb going over the threshold and the ECU cut the fuel again, over and over. It's caused by too much air getting past the throttle plate.

The IPS also acts as the stop for the throttle plate, so it's adjustment is critical. Too far in and the throttle plate is held open (allowing too much air to pass), to far out and the plate can bite into the throttle body.

Steve