I've been reading and searching around for some info maybe someone can help.
To start with its an 89 cherokee with 4.0 auto.
Problem 1: cranks for a long time before it starts. read some suggestions on fuel system pressure and also cps Also read starter no good (not spinning fast enough) but it's brand new.
problem 2: sometimes when i start it up, it idles at 2000 Shut it off and restart and sometimes it's fine and sometimes it idles high again. read that idle motor bad, but replaced with 3 others works for a while then there it goes again

Any info would be appricated.

 

Not the idle air controller... the idle problem sounds ALOT like a TPS either out of adjustment or bad.

Cranks how long??? Renix Jeeps will normally crank longer than other vehicles.

 

yes that jeep will crank a couple seconds longer than anything else. i had a 1990 that did the same hi idle on start up, only at times. shut it right off, start again and fine right. i tried everything, clean the throttle body, iac, tps, lube throttle linkages. can't remember how it turned out, i think it stopped.

 

My 93 XJ cranks for a bit too.. usually 2-3 secs.

 

Will have to see what I can find but it sounds like a latch relay problem. I have read about this but never actually seen it happen. Whowey do you have any latch relay experience? Know of a fix for a defective or intermittent latch relay problem?

 

Found this thread on NAXJA and it shows where the latching Relay is located and as you may have guessed it controls the IAC motor and thus your idle. So when the IAC motor is new and you are still experiencing different idle speeds then the latching relay may be the culprit. You can switch the relays around in that group of four relays to see if it is the relay itself. HTH
Blue
http://www.naxja.org/forum/showthread.php?t=944652

 

I had a problem with one.... But it was cracked and the moisture had corroded most of the inside of it...

Honestly, I had completely forgotten about the relay... Seems like I had swapped out the A/C relay to test it.. But always remember to put your A/C relay back even if your A/C doesn't work. The A/C and the fuel pump relays are the same. Nothing like carrying a spare fuel pump relay right under the hood in an emergency.....

 

Thought of another cause for the erratic idle problems. Loose intake manifold bolts will cause those same symptoms too. Check their tightness and if they are loose then that might explain the symptoms. Sry I didn't think of this sooner, getting old and not as sharp as I once was.

 

What does the latch relay do? And is a malfunctioning relay affected by the weather. I have the idle issue described above it gets worse in hot weather and almost disappears when the cooler fall weather hits. I have replaced the O2 sensor and cleaned the idle controller. Still trying to figure out the problem.