Hello everyone , I own a 1999 jeep cherokee sport with a 4.0 inline 6. My jeep shuts off while driving and the check engine light comes on then goes off. It starts right back up again but i rarely make it a block. I replaced my fuel pump assembley yesterday hoping that was the issue but as i awoke this morning and tried to drive to work once again it stalled , check engine light flashes and goes off , this time my oil gauge went straight to 80 and stayed there. Any ideas what this can be?

 

Pull the codes. Even though the check engine light shuts back off it should be storing the code

 

Mine's been doing this as well, but it's my cat converter that's causing it because it's so old and rotted out. My oil pressure will stay fine though. Try to check for any codes the engine is giving

 

When I had that issue, it was the crank angle sensor failing. I got no CEL and no other symptoms. Since you had a CEL, I agree, pull the codes.

 

I tried pulling the codes,but nothing comes up. I checked the ground wire on the passenger side of the engine block , moved it up and down and it stalled.I have replaced the ground wire. It ran for a while then died once. Shook the line again on the passenger side of the transmission it stalled and started back up then I moved a wire near the cat sensor and it hasn't stalled whiled driving, very weird.Robert_b whats the crank angle sensor?

 

Cant pull any codes, the check engine flashes then goes away.

 

Wiki:
A crank sensor is an electronic device used in an internal combustion engine to monitor the position or rotational speed of the crankshaft. This information is used by engine management systems to control ignition system timing and other engine parameters.

On your 99 XJ, it's on the top of the transmission bell to the left side (approx. under accelerate pedal). You can see it from the engine bay. Two bolts. It plugs into the engine harness on the left side of the engine near the fuel injector rail (rear). Common part to fail as your Jeep ages. I recall the OEM part is about $80. It's a bit tricky to replace because of the location. You'll need a long socket extension or two with a swivel. 10 mm socket I think. I not certain this is your trouble but a good candidate.

 

Is there a way to test the crank sensor?

 

Haynes says you can use an ohmmeter to check it.
'92 and earlier: terminal A to B open
'93 and later: terminal B to C open
I would assume this would be a total fail of the sensor.
Mine was an intermittent fail that was not detected by this test. It would stall while cruising. I could restart and not have any problem for days or weeks. Then same thing. I replaced the sensor a year ago and no more problem.

 

Mine ended up being code P0320 which was the CPS sensor going bad, Not my cat, sorry for the misinformation.

 

Thanks!

Do you happen to have a diagram of plug to determine which terminal is which? I tested (don't remember which terminals) and showed 580something ohms.

 

https://www.cherokeeforum.com/f51/testing-cps-5563/

 

My plug looks different. It has flat blades, and any other indicators of which way to hold it do not match. I'll try to get a pic.

 

 

I think I matched the square key tab to the diagram.