1G Idle Speed Control

[SinisterRacingDSMJMC]

Need help! My idle keeps bouncing from 2,000 and 1,000 sometimes it holds I'm pretty sure it's anot idle speed control sensor. Can anyone point me in a direction to where I can get one. Also, could it be possible that an exhaust leak could be throwing off the 02 sensor to throw off the idle I'm fixing the leak at the downpipe tomorrow to see if that's it. However, still think it's the sensor. Again can anyone point me in the right direction for an ISC sensor for a 1g 1990.

 

[nwBryce89]

You can test your isc using a digital multimeter, there is write up on vfaq on how to do it. I would first start by looking for vacuum leaks, build yourself a boost leak tester and see if any air is entering or exiting after the maf.

 

[steve]

That tests the the coils aren't shorted or open but doesn't test the the ISC works.
For that you need to pull the ISC and verify that it steps in and out when you power the ECU up. The ECU homes the ISC as part of the startup process.

 

[miguelmcv]

Describe the problem a little better, if idle goes up and down constantly when idling then it should be a boost leak, but, if it does it randomly then it can be the ICS.
As both posts before stated, first test the ICS before replacing it.

 

[zedicus]

i have had more FIAVs go bad than any other issue with throttle bodies on these cars. just 1 more thing to consider.

 

[SinisterRacingDSMJMC]

Ok, here's a little more info. I started it up for the first time the other day after I replaced the oil pan. And as soon as I started it up.... it idled at 2k then bounced down to about 1.5 then back up to 2k and so on and so fourth. It held after I reved it up a couple times but it was idleing then around 2k and then went back to bouncing between 2k and 1.5 and 1k

 

[SinisterRacingDSMJMC]

Appreciate the help though guys!