zone zero

So I'm at the point that I might have to sell my completely rebuilt Cherokee
I'm talking new engine trans axles paint interior and a bunch of after market parts mostly ARB

So these are the issues I'm having .
Starts fine when cold, on days that are below 45 it runs ok anything hotter than that when I shut it down it will not restart and needs time to cool down.
Check engin lights on
The codes listed are these
Coil pack A
Coil pack B
Coil pack C
Inter minted signal between Crank position sensor and cam position sensor.

Have had 22 hours of diognostic done on the truck to the tune of $1800
Can't figure out what's going on.

The hole truck after rebuild only has 40,000 on it now . Problems started last fall and have become a safety hazard.
The jeep will speraticaly die when driving. When this happens my rpm gage will go up but the engine will bog down and stall out. I can shift to neutral and start it and it takes off and runs fine.

3 weeks ago I replaced the cam and sensor , the crank sensor, plugs, coil pack rail, fuel injectors
Battery, battery cables

I drive the jeep about 150-200 miles a week, and it died at 75 mph on 95 north bound the other night. I'm won't let my wife drive it now until I figure out what's going on.

The local jeep dealership won't touch it and any of the local shops want to throw parts at it.

I'm wondering if it could be a bad computer.
If I can't get it fixed I'm going to have to find another jeep and shelf her
I'm really bummed out.
In total I probably have $18,000 into this jeep from all the new parts, everything was built with a purpose
We use the jeep for long range expedition trips and have a big one planed for the summer.

Basically I need some help guys.

zone zero

travs2448

Had all the same issues you did on my 2001. and went through pretty much all the same diagnostic steps. It ended up being my camshaft position synchronizer. Which is the part that the camshaft position sensor goes in to. Take the cam sensor off and see if there is any play in any direction with the pulse ring that spins.

Also check your negative ground cable from the battery to the body of the jeep. as this broke off on me from so much rot when i disconnected the battery to do this repair. so its hard to say whether that was more or less a cause of the problem. It seriously took me about a week or two of forum jumping to figure this out. Actually came across the issue on a TJ forum. Since only 2000-2001 cherokees have this part i suppose its not a widely talked about issue here.

zone zero

Thanks I'll have to double check that see if there's an issue have you hear of anyone having a computer crap out on them?

Fred/N0AZZ

It has happened but most of the times it came down to wiring issues in the harness/connectors somewhere. Its very hard to tell most of all anyone trying to help online and sounds like you have tried at local shops.


Wish I had a more solid answer for you, how long did it run without any problems when you got it back after the complete rebuild?

Hapdad

Any possibility that this is related to heat soak? Is the heat shielding in place? The fuel in the fuel rail can boil and thus vaporize. When things cool down the fuel condenses and life is good again for a while. I would elaborate on this if I knew more about it but this is one of the things I looked at on a previous jeep I had with similar issues and was ruled out when the fuel injectors started leaking fuel and were replaced. The problem disappeared afterword.

zone zero

Well I did the complete tear down and rebuild myself I have had 11 jeeps and 2 land rovers over the years this is my 4 th Cherokee.

It ran fine for about a year with no issues. Then started acting up in the summer on hot days, now if I see the forecast is above 45 I plan on having trouble.

The heat shielding is in place and I have added 2000 degree heat shielding under the injectors and have wrapped them in the same shielding. The grounds are good and have been replaced when the truck was rebuilt we checked everything we could. I spent 17 hours of my own time with a Mack tools diognostic computer, it keeps saying its intermittent signal between the cam and crank but the wiring test out fine the signal voltage going out and coming back is consistent during start up and running.

We even took out my friends coil pack rail and swapped them I used his for 3 days he used mine. Mine, ran like **** his ran fine. So we know the rails good

We checked all the computer ends for signal they tested out fine. It's a nightmare.

LAF1269

I had a similar issue on my '98. It ended up being an issue with the wiring harness. The part of harness that passes behind the head had come loose from the stud, and was hanging lower and close to the exhaust. The Jeep would run great until it warmed up, but would "buck" pretty badly and not restart when it was at operating temp. If i waited until it cooled down, it would start every time. I chased that issue for quite awhile until I finally repositioned the wiring harness, and it fixed the problem. I haven't had an issue since. It may not be your problem, but it's something to check.

travs2448

http://www.askamechanic.info/askamec...nt/view/55/47/

This is the article that caused me to start suspecting it was the synchro. Its a good read. Mean to post it last night but couldnt find it

zone zero

Thanks for the helpful info, I'll be checking the electrical line by line this weekend, it's a pity no one makes a replacement harness for the Cherokee. I'd be in for one.

Turbo X_J

Your not using dielectric grease on any of the electrical connectors are you? (other than inside spark plug boots)
Blast of this on any and all connectors sure won't hurt anything.