1G Idle Position Switch and CEL only at idle

[Dsmturbo]

Hi guys, I've been researching this check engine light issue I'm having but can't get it sorted out, hopefully you can help.

I'm working on my brother's 1g gst and his check engine light comes on only when the car is at idle, however the car idles perfectly. The second you give it any gas the light goes away until the revs come back down to idle and then the cel illuminates again.

If i remove the connector on the idle position switch the cel goes away but the car searches for idle and can't find it so it's all over the place (surging 500rpms-2000rpms). If I pull the idle position switch out and put my finger over the tip of the sensor then the cel comes on, if I take my finger off then cel goes away (this is with the car in the on position).

I've tried adjusting the ips but there are only two options, it's tightened down and I get a cel or it's too loose and the car can't find idle. Any ideas? Thanks everyone!

 

[Paintballaa5]

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It is possible the idle position switch needs adjustment. I'm not sure if it will throw a CEL, but test the switch as shown in this video. Start at 2:00 for info on the switch.

 

[Dsmkauai]

So are you talking about the Isc (idle switch controller)? It's possible it's just bad which it kinda sounds like.

 

[Dsmturbo]

Sorry guys I had to go out of town, I did get the car fixed, it was the tps. Thanks Paintballaa5, great vid!

 

[Paintballaa5]

Sorry guys I had to go out of town, I did get the car fixed, it was the tps. Thanks Paintballaa5, great vid!

Glad you got it fixed! Check out his youtube channel for a wealth of information about these cars!