1995 Jeep Cherokee emissions controls

Avatar
DMANAGER
  • MEMBER
  • 2 POSTS
Engine Performance problem
1995 Jeep Cherokee 6 cyl Four Wheel Drive Manual

Lets try this again , nitrous oxides are at double plus the allowable for this vehicle. All other parameters are well within spec. at half or less of allowable. This generally leads me to the E.G.R. loop , either the ports are plugged with carbon , or the E.G.R. valve is not functioning. To the best of my visual , there does not seem to be an E.G.R. at all on this vehicle. I have pulled the throttle body and looked in the intake for any signs of coking or carbon from an E.G.R. , but see no signs of such. Is there something else that would raise the NOX levels without affecting driveability ?? F.Y.I. I am A.S.E. cert. PARTS not Tech. This is making me nutty. Thanks for your consideration.
Oct 5, 2009 at 11:31 AM
Advertisement
Avatar
RACEFAN966
  • ✓Experienced Mechanic
  • 5,029 POSTS
Ok this could be caused by either a bad O2 sensor or a bad Cat. Nox output is higher when the temp is higher this is natural. So with that how hot does you Jeep get? How old is the oil? How old are the spark plugs? If anything here is old or if any plugs are worn then the combustion temps may be getting high which will produce more Nox. If you plugs are new then I would check for the proper heat range too. If the plug heat range is to high then it will raise combustion temps and again produce more Nox. You don't have a PCV it is just a vacuum hose from the intake to the valve cover check the orfice in the manifold where it connects and make sure it isn't pluged. You do have an egr valve, it may be underneath the manifold but there is one, here is a pic of it.


https://images.2carpros.com/forum/automotive_pictures/249564_egr_1.jpg

Oct 5, 2009 at 12:03 PM
Add a reply
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.

Frequently Asked Problems for This Vehicle