Inconsistent high idle - very strange - Help? - Page 2 - 3000GT/Stealth International Message Center

jcr5186 · 10-28-2009, 10:40 PM

I cleaned my IAC with electronics cleaner and ohms tested it. Seems to be in good working condition. Also replaced the caps on my ECU. My car generally idles about 1700 when cold and about 1200-1400 when warm. Also it will fluctuate and rev up and down between the two. Any ideas?

Jon

Stealthee · 10-28-2009, 10:48 PM

Possible vac leak.

jcr5186 · 10-28-2009, 11:57 PM

I did the vacuum line delete mod and pressure tested yeilding no leaks. I would imagine it would have to be reasonable size to make it flucuate idle so much?

frozenevolution · 10-30-2009, 04:35 PM

I completely disassembled the IAC and cleaned the grimey parts. All pin's ohm'd out to mid 28's, which is good.

So I reassembled it and put it back on the car, now if I'm driving and come to a stop the idle fluctuates from around 1200-1800 very quickly, constantly going up and down until the car starts moving again. Could the IAC just be crapped out and need replacing? Or would something else cause this?

Stealthee · 10-30-2009, 05:34 PM

Its possible the pintle is malfunctioning, I guess. If it ohmed out good and is still not idling properly then the next logical step is swapping it.

turbodevil91 · 10-30-2009, 06:35 PM

I recently had Idle fluctuation! Going the cheap route I decided to go ahead and clean it with electronics cleaner spending a total of 1hr of my time, immediately my car idled perfect for about 2 days then suddenly it was back to its old ways again. For what its worth replace it with a new ISC save yourself the trouble go spend $84 at Napa and buy a new ISC MY car idles perfect now "Idle steps up and down like fluid"

Stealthee · 10-30-2009, 06:48 PM

Better yet go spend $70 at Rock Auto and get the better black bodied ISC. Part number is AC99.

jcr5186 · 10-30-2009, 09:11 PM

Well frozenevolution... looks like we need new IAC's.

Defianse · 10-31-2009, 12:30 PM

Quote:

Originally Posted by Blurr

IAC

Get some electroncs parts cleaner and a toothbrush that you don't care about anymore. then read this.

Stealth 316 - ISC Servo Motro

The section that you're looking for is toward the bottom of the document.

This is an excellent article! Thank you very much for providing this link.

frozenevolution · 11-07-2009, 12:12 PM

Quote:

Originally Posted by jcr5186

Well frozenevolution... looks like we need new IAC's.

You might be lucky and just need that, I don't think I am though...

Sorry about the time gap everyone. I ended up putting in a new IAC. Long story short, it didn't do anything. Still idle's high. After I put it in it idle'd around 1600/1700. Staying probably around 1500 right now. It still does the thing when you pull up to a stop, the rev's will go up and down jumping by about 500/600 +/- from the current idle rev constantly until I start driving, but it does not do this all the time; when it's not doing that, it just idle's high.

Any other suggestions that would cause this? Thanks