NAXJA Forums -::- North American XJ Association  

Go Back   NAXJA Forums -::- North American XJ Association > NAXJA Unibody Jeep Technical Forums > Jeep Cherokee XJ (1984 - 2001) > OEM Tech Discussion
HOME Member FAQ Sponsor Info Rules Bylaws E-Mail

OEM Tech Discussion Forum for OEM (Original Equipment) or stock XJs and MJs.

Reply
 
Thread Tools Display Modes
  #16  
Old December 5th, 2016, 13:36
old_man's Avatar
old_man old_man is offline
NAXJA Member
 
Join Date: May 2003
Location: Loveland, Colorado
Posts: 15,303
Re: Another xj missfire thread

120 isn't great compression. Did you also do a wet test?

As far as having more power when the CEL is on, it may be running open loop (richer).

I would do a vacuum check. Look up what to check for. It isn't just a single value but if it is bouncing around. 15 isn't that great either at your altitude. You could have a vacuum leak or clogged CAT.

I would swap the #1 coil pack with another cylinder and see if the problem moves.
__________________
Tom Houston - Former Colorado Chapter President & Terminal Adrenaline Junkie
Loveland, Colorado
You're just jealous because the voices don't talk to you.
Reply With Quote
  #17  
Old December 5th, 2016, 16:11
Ohsplat Ohsplat is offline
NAXJA Forum User
 
Join Date: Nov 2016
Location: florida
Posts: 18
Re: Another xj missfire thread

All injectors are brand new. Used a noid light and all injectors fire. Same issue with old injectors back in. So the injectors are new and ticking. The plugs are new and putting the old ones in did nothing to help. I'm just throwing parts at it now. No idea if maybe the cps is a OEM or mexico made autozone turd. I've had this issue since I had the jeep.
Reply With Quote
  #18  
Old December 5th, 2016, 16:12
Ohsplat Ohsplat is offline
NAXJA Forum User
 
Join Date: Nov 2016
Location: florida
Posts: 18
Re: Another xj missfire thread

I changed the back o2 sensor when I removed the cat, but the front one is pretty rusted and frozen in. I could not break it loose to change it.
Reply With Quote
  #19  
Old December 5th, 2016, 16:14
Ohsplat Ohsplat is offline
NAXJA Forum User
 
Join Date: Nov 2016
Location: florida
Posts: 18
Re: Another xj missfire thread

Quote:
Originally Posted by old_man View Post
120 isn't great compression. Did you also do a wet test?

As far as having more power when the CEL is on, it may be running open loop (richer).

I would do a vacuum check. Look up what to check for. It isn't just a single value but if it is bouncing around. 15 isn't that great either at your altitude. You could have a vacuum leak or clogged CAT.

I would swap the #1 coil pack with another cylinder and see if the problem moves.
The cat is gone, I'm at sea level pretty much in Florida. So your thinking its the engine? I thought dry the pressure of 120 was fine. The manual states 120-150 with no more then a 30 difference I believe.
Reply With Quote
  #20  
Old December 6th, 2016, 08:24
90xj06's Avatar
90xj06 90xj06 is offline
NAXJA Forum User
 
Join Date: Aug 2006
Location: Peabody, MA
Posts: 1,665
Re: Another xj missfire thread

do you have a way to test for spark? thats the only thing left.
Reply With Quote
  #21  
Old December 9th, 2016, 08:06
Ohsplat Ohsplat is offline
NAXJA Forum User
 
Join Date: Nov 2016
Location: florida
Posts: 18
Re: Another xj missfire thread

Just as a follow up for people with the same problem. I sold the xj because it was a engine problem. When my mechanic did the leak down test it was not having the idle issue. I bought my own gauge and waited for the problem to arise. I performed a compression and leak down. Compression was less then 100 and air leaked out into the valve cover. Seems after talking to a master tech at my local jeep dealer that the 2000-2001 xj had a known issue of the exhaust and intake valves not rotating. This causes them to wear funny and only seat right in one position. This caused my intermittent problem. When I high reved the engine it would cause them to rotate and not seat correctly for a while. Hope this helps others with the same issue.
Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
CEL and Missfire -rhino- OEM Tech Discussion 6 October 24th, 2016 21:19
missfire on cyl 1&6 or it seems that way ryan72490 Modified Tech Discussion 0 March 3rd, 2013 23:49
Missfire... ?? Doose-doe OEM Tech Discussion 4 December 29th, 2011 10:25
4.0 missfire cordog OEM Tech Discussion 4 May 12th, 2006 23:08
4.0 missfire abes OEM Tech Discussion 12 September 7th, 2005 07:26


All times are GMT -7. The time now is 07:49.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
NAXJA and NAXJA logo's Copyright NAXJA. All content/images Copyright NAXJA 1999-2014