Volcomroofus

First of all I don't know much but I'm learning as I keep having to fix things as they come up. Which lately has been more often than I can fix them.

Alright I've got a delmia. My truck was running fine on sunday then when I jumped in to go to work on Monday morning it wouldnt start. It would crank but not start. The battery read kinda low around 10v So we tried a jump and that wasn't it. My friend was telling me it might be the CPS, so I researched that alittle bit on here. I found http://www.go.jeep-xj.info/HowtoCPSchange.htm and in there it states,
“The problem is that when the sensor starts to fail, you get no spark or fuel so it will either not start, or suddenly without warning, stop the engine while it is running!”

There have been a few times (probably 4 in the past month) where it would just shut off on me while driving. It would happen only when I turned sharp, like the 90*. The fuel light came on so I figured I was just running out of fuel. My fuel sensor is out, it used to read everything under a half tank but now it just stays at E all the time. The light still comes on with audible so I know when I'm really low on gas. Ever since I filled it up it hasn’t happened since. Could it have been the CPS going bad instead of me running out of gas?

My main question is where do I start to troubleshoot to make sure it's the CPS and not another problem? The fuel pump turns on and I have fuel going to the engine... I know this has been answered before and I just keep finding that it's the CPS, I want to make sure before I order parts though because I have to pay 150% duty on things and labor is CRAZY expensive here. I don't have too much free time or tools to work on my truck on a blacktop parking lot in the hot *** caribbean, I'm trying to cut my time down under the hood..

superj

the only way you can be sure its the cps is to find hte specs on the sensor and check it with a multimeter. if its out of spec then its bad. also though, wiggle the wires going to it while checking stuff because i have found cps (on other makes) where the wiring harness was bad at the cps (where the wires go into the actual sensor) and would read good if you held it a certain way and bad if you hit a bump and it shifted some.

Volcomroofus

What about a stuck throttle body?? Could that be the problem?

BlueXJ

no keep looking for the cps specs.

Volcomroofus

Alright you have to bare with me because I'm learning about engines as I fix things... Never took a class in highschool or anything for that matter. The most I've done before this jeep is basic parts replacement on my jetski and the usual maintenance on my 5.2L dakota. Which by the way was a hell of alot easier to work around than this 4.0L lol.

This is what I found to check for the CPS..
From: http://www.jeepforum.com/forum/f11/9...ew-cps-924600/

"TESTING PROCEDURE 1991 – 2001 4.0L H.O. engines

1. Near the rear of intake manifold, disconnect sensor pigtail harness connector from main wiring harness.
2. Place an ohmmeter across terminals B and C (See Image). Ohmmeter should be set to 1K-to-1OK scale for this test.
3. The meter reading should be open (infinite resistance). Replace sensor if a low resistance is indicated."

He also suggested checking the O2 sensors for shorts or opens. Now my O2 has been bad for a few months now, but I was told it isn't a nessesity to get fixed. My CEL is on and when I hook up the diagnostic the O2 comes up. Not really sure what the O2 would do to make it not start, is there something that would make it not start with the O2?

Now a stupid question, even though no question is stupid right, What specs exactly am I supposed to be looking for, for the CPS? I'm guessing you're talking about what ohm tolerance the cable should have like the guy states in the testing. I searched the internet for 2000 xj CPS specs and all I get are forum threads. Cant find anything in the manual, would the chilton's have it? I'll try to dig that out of my closet while at lunch today...

Volcomroofus

okay, found this..
https://www.cherokeeforum.com/f2/jee...art-help-5451/

When I get off work today I'll try the unplug clean replug trick. I have no patience in the 90* heat with no shade and once the sun goes down alittle and cools off the misquietos come out. I'm hoping this is just a dirty connection. Part of Montserrat's volcano canopy collapsed and the wind shifted towards us. We're only 30 something miles away and there's ash EVERYWHERE. Some people down south even reported that the ash was so fine it got between the pages of closed books on the bookshelf. I'm gonna check all that stuff today right after work around 4pm EST. and come back with any info I have.

claygrassmann

well basically if you are gettin spark and gettin fuel then its pretty much the cps try rockauto.com for cheap parts