300 rpm idle question

[bstclum]

Ok I bought my 1g turbo awd talon and I noticed that it idles real high (3000 rpm). So i Looked under the hood and there was a sensor unpluged on the tb, I plugged it in and the motor pulsates(revs high and then low). When i unpleg it again it revs back to 3000. What could this be and is there a fix?

 

[DSM90AWD]

I'm guessing that sensor is the ISC which the ECU uses to control idle.
I suspect the previous owner was not to savy in fixing his idle surge issues so unplugged this and set ide via the BISS screw.

If it were me, I'd try cleaning the TB/ISC, resetting the base Idle, check base ignition timing and curing any boost/vacume leaks to see if that corrects the Idle surge issues

 

[steve]

Unpluging the IPS (Idle Position Sensor) will stop the idle surging by tricking the ECU into not knowing when the throttle is closed.

The ECU won't then use the ISC (Idle Speed Control) stepper to manage the engine idle speed since it doen't think the engine is idling.

Steve

 

[ddavisaf]

.... test and replace the ISC. www.vfaq.com under intake