New 01 Cherokee (70,000 miles) been in the shop for over week on this and they are ready to give up with no solution. Need some help. Runs & starts great. Throws a code/engine light comes on after about 7-10 miles. everytime. Motor was recently out to replace cam bearings, oil pump and pickup by guy who sold it to me. Did not have this issue before that. Original issue was low oil pressure. Thought it would be something quick and simple that guy forgot to hook up. These guys have gone thru everything a couple times now. Replaced coil paks and computer. still does the same thing. They've checked ground, cam sensor, plugs, wires, etc. They are saying maybe fly wheel was put on 180 off. I think they are out of ideas. Anyone got any thoughts on this. This shop is usually really good but they are stumped on this one. any help would be greatly appreciated.

 

When a shop says the flywheel may be installed 180 degrees off, find a new shop and have them do a cylinder leak down test. The flywheel will only bolt on one way.

 

Yupp id start with a compression check, check injectors, fuel sender, and fuel pressure regulator as well

 

Yeah, I think they are at wits end with this. They have checked the compression a couple of times already, says its good. Replaced the plugs, coil packs, still nothing. Traced the wiring back to the computer, say no cracks. Replaced the computer today, no help there. What is a leak down test? Never heard of it.

 

Yep, check fuel pressure. For some reason, low pressure seems to cause misfires on 1 and 6 (not sure why).

 

ha I knew I was right but a bad regulator could cause high or low pressure, both are bad. I have a 96 and the pump, regulator, and sending unit are a one year 96 specific one piece unit. Some other years have individually replaceable parts. But 96 is all one piece, non serviceable

 

You're not right yet until the problem is solved.

 

true shi* right there

 

Thanks for the ideas guys. I will pass it on to the shop but I think I will pull it from them first ( flywheel off 180)and go back to the guy I bought it from. He is easy to work with and a standup guy. Will post up what happens
Thanks

 

Ok Guys, here's the scoop. Cherokee is running like a top. Still need to put a few miles on it to make sure but the shop ran it just about out of gas to verify its good. Now the good stuff. After the install of the new cam bearings, Guy I bought it from said he reset the cam sensor but apparently it was not right. The shop checked it multiple times and swore it was dead on. They called Chysler and thru a friend there told them the specs in the book they had were off by 20 deg. I guess that you can disconnect the computer so it is "stupid" and it is supposed to "learn" the setup and make minor adjustments. With it being 20 deg off, it was too much. When they calibrated to the #'s from the Chysler guy, all was well. I may be off a bit on the terminology but basically that's how they explained it to me. I drove it about 15 miles around town and it seems to be running strong and solid. Thanks again for all of your help as yesterday I was at wits end with the shop & the Cherokee. So I'm going to celibrate with an H4 headlight conversion & putco relay setup this weekend. If all holds well, then comes the RE 3.5 lift, wheels and tires!!!

 

Glad they got it fixed for you! Thanks for letting us know the cause.