87 XJ 4.0 Runs rough @ backfires

sarwolfco · 11-03-2002, 06:31 PM

Just put a new engine in my 87 XJ. When I first got it going, it ran OK. Now, with about 200-300 miles on it, it runs REAL rouch about 2500-3500 RPM, and backfires & sputters at high RPM. Also, it smells like the air/fuel mixture is REAL rich....I'm LOST. Any ideas on what I can try?
Thanks!

XJBill · 11-04-2002, 12:13 PM

you have tried the timing right? sinces its not carburated thats the only thing i can think of

sarwolfco · 11-04-2002, 03:01 PM

I did, but, unfortunately the timing is not adjustable. All i can think is to replace the computer or ignition control module.

**balloo93** · 11-04-2002, 03:39 PM

Check out the #10 mod on this site. This might be what you need.

http://4wdandsportutility.primediaautomotive.com/archives/tech/0501_tech02.shtml

I assume you either replaced the timing chain or knew that it was good. If the chain was put on wrong it will give you same problems due to bad timing.

11-04-2002, 12:13 PM	#2
XJBill Registered User Join Date: Sep 2002 Posts: 515 Profile Gallery Classifieds My Jeeps	rough you have tried the timing right? sinces its not carburated thats the only thing i can think of

11-04-2002, 03:01 PM	#3
sarwolfco Registered User Join Date: Nov 2002 Location: Colorado Springs Posts: 3 Profile Gallery Classifieds My Jeeps	I did, but, unfortunately the timing is not adjustable. All i can think is to replace the computer or ignition control module. __________________ SARWolf Colorado Springs, CO http://www.sarwolf.com