I am getting an intermittent Check Engine Light. By intermittent, I mean I can drive my XJ 5 times or more in between times and it runs fine with no issues. When the CEL comes on, it is during just normal mid speed, I.E. 45-55 MPH driving. It stays on until I pull over and turn off the engine, wait 5-10 seconds and restart the engine. A couple of times when shutting off and restarting the CEL did not go away but, everytime after leaving it sit for awhile and restarting the CEL will go away. The only other accociated problem I see when the CEL comes on, the volt gage dips down to around 8 volts. My gage is always right on or very near 14 volts when all is well. I was thinking bad alternator but, everytime I have ever seen an alternator go bad, they just go bad and quit putting out. I've never seen an alternator go bad intermittentantly. I was wondering if any of you guys have seen this with your XJ 4.0 motor before....and better yet, what fixed it.

 

I had the same problem on my 98 it was the altanetor. the regulator went bad inside of it.

 

Thanks for the quick relpy, bro. I figured it was most likely the alt. or reg. which are all in one. I was just hoping it wasn't as.....in the last month and a half I've done a starter, vibration dampener, serpantine belt x 2, water neck gasket and water pump gasket. My Jeep hasn't handled the summer to winter weather change too well.: brickwall:

 

i put a junk yard alt on mine and it worked fine too cheap to buy a new one plus it came with a warranty

 

Hey I never thought of looking at the junkyard. My local junkyard only has an 88 XJ left out in the yard but, they recently crushed 3 XJs that they'd had for awhile. They might just have an alternator on the shelf inside. Thanks for the help.

 

anytime

 

Insted of starting a new thread ill ask in this one. Maybe mine is the alt. also. Becuase if i jump the battery it will run but it wont charge the battery while running and also my jeep if i drive it and get on it a little bit the check engine light will come on and then if i let it sit for about a hour and go to start it the check engine light wont come on. Do i have the same problem as him?

 

I would say either the alt or a bad ground.

 

I've already been through my cables end to end when I found my starter bad. This Check Engine Light thing just started happening a few days ago. I'm sure mine is the alternator, just a VERY spendy thing to have to replace just before Christmas.

 

mine was from a jy for $30 with a 60 day money back warraty