1G ISC circuit control

[mjdarg]

I have been having idling issues for the past 6 months or so I have just been dealing with it. There doesn't seem to be any consistent pattern to it. Sometimes it idles around 1400 while driving around and just last night, it was around 800. I've got a logger and I have noticed that with the higher idle, my ISC steps were 76 or 77. Last night with the lower idle, it was at 42.

When I turn the wheel, I can see the ISC steps increase by 15 to compensate for the extra load. I have noticed that the rpm will go higher than normal when I turn the wheel. It seems the ISC is opening too far. Turning on the headlights and rear defroster does not change the ISC steps and the idle will drop about 200 to around 600.

I sent my ECU out to ECMlink a few months back and they said everything checked out fine. I've checked the resistance on the ISC and everything is good there.

It seems like the ECU isn't getting the proper signal to adjust rpm with the ISC, but I'm not exactly how the circuit works. Does the ECU, just use the rpm signal or is it more complicated than that?

 

[lee98talon]

From my experience, I never got my isc value to read steady at ~30 on ecmlink at idle. I believe on the ecmlink wiki page, it says to set the isc to read close to 30 at idle which then will give you the ideal idle, ~750rpm.

As of now at idle my isc reads 0 at ~850rpm on ecmlink. And the isc value does bounces when I give it throttle. I get a little idle surge sometimes. But, I like having my idle a littler higher the 750rpm any ways and I like it.

 

[Nuzzi]

make sure your tps and idle switch are in good working condition and the throttle stop is adjusted properly. These will all affect each other.