I've been so upset I have had the title in hand ready to trade it in. OK calm down. 1988 cherokee, manual trans. When it's cold idles at 900. When it's warm it idles at 1200 rpm. 800 would be better. I've change out every sensor on the motor ( used ) except the CPS. Put a new O2 sensor. New manifold / exhaust gasket. And rechecked for manifold leaks. And yes it has the C101 wiring harness. I have adjusted the TPS on two different sensors. My guess is my Idle control valve is getting the wrong volts. I can't find anywhere the four wiring specs that go into the ICV. I need to prove the ICV is getting the wrong info/volts. I have a wiring harness out of a 1989 that does not have the C101 plugs, but it still has my style of connectors. also got the ECU from that 1989. I was getting ready to install the harness and ECU on my jeep. But I would like to isolate the wiring problem, if that is what it is. I thought I was a smart guy, but this Jeep-High Idle has nearly broken my spirit. Your help is needed. Also if anybody knows a Jeep Geek in the Seattle area let me know. I need a expert on this 87 to 90 Renix. I read and printed the Renix manual someone posted. That was a huge help. But did not tell me about volts into the Idle control valve.

 

Also I'm new to this forum thing. If I'm in the wrong area or doing this wrong please help. Thanks Stocker

 

Let me see if I understand this, your replacing used parts with different used parts? I guess that's OK as long as the replacements are known to be good.

Now to properly see what the IAC is doing (signal/response) you would have to use an ocilloscope because it (not unlike a fuel injector) is driven by pulses (+ - Hz.).
What happens if you start the engine cold with the IAC electrical connector removed?
Have you removed the vaccum lines & plugged the ports?
Are you sure the manifold & head mounting surface are true?

 

did ya check vavuum line at vacuum ball ?

 

I know i have been using used parts. Not made of money. It seems if the system was working right it would choke, or high idle when stone cold. It runs a low idle when cold. Then creeps up to 1200 rpm. Can't find a vacuum leak. Wish i could. After reading the Renix manual. I need to know is the ECU receiving the temp signals and is it sending signals to adjust timing and idle. I've tried unplugging everything one at a time with know change. Not the best way to check. But I'm trying.

 

have you seen this...http://www.eriejeeppeople.com/ejpfor...?showtopic=217

 

-well played sir

 

 

-this is the kinda response ya want,if yer a newb and in a 9-line-bind, and at yer wits end, not do search ya moron, who knows? maybe a new member? kudo's Free

 

All else aside, have you cleaned the IAC? Something to do anyway, and maybe will help.. move forward. Un-plugging it, I gather, just leaves it set where it is. There is a deal on that Cruiser 54 did in my signature, as well as some other Renix stuff.

We no longer have the idle speed screw from carb days. The butterfly sits on it's stop, and the IAC lets air through.