Engine dies while driving
 

First off, I appreciate it if anyone makes it through this long post. My fiance is using my 2001 XJ Auto 164,000 mile rig as her daily driver, so fixing this matters. If she didn't need it every day for work I'd probably let it sit outside and tinker with it whenever I had free time. Alas, this is no longer the case.

A little background,3 years and 30,000 miles ago I had a trail failure of the crankshaft position sensor. We had to use an Advanced Auto sensor because there were no dealerships or parts depots in the area. It was a horrible experience replacing it on a cold October afternoon, 4 miles from a road and about 80 miles from home, with the sun setting and rain coming, but we got it in and I haven't had any related issues, until maybe now. I know a Mopar sensor is preferred.


2 weeks ago I finally got around to replacing the fuel pump with a Bosche unit. I had been living with a “prime it 3 times before start” procedure for 4 years, but decided to replace it before it failed on me. During this repair I noticed that the evap line going to the canister was very rusty and the rubber fittings are pretty beat up. I assume this is causing my small evap leak code. Now it starts up immediately, no extended cranks and no priming needed.


Onto the big problem: engine dies while driving. Takes multiple attempts to start, always starts after an extended crank. Always dies within 3-5 minutes of engine starting up cold.


9/6 1st occurrence:
Sunday afternoon driving to Kohl's. Got 2 miles from home and it died. Tach does a slight gauge sweep, it’ll climb about 500 revs then drop back to normal, and it does this 2 or 3 times. Engine speed doesn’t increase during the tach sweep, but there is a minor hesitation, then the engine shuts down. 3-4 starting attempts, no start. Sat scratching my head for 2 minutes, finally extended crank and start. Drove it to Kohl’s, then a few test drives with no problems.



9/6 2nd occurrence:
Sunday night on my way home from my aunt's, it had been sitting for about 6 hours. Got maybe 2 or 3 miles from Aunt's house and died. Gauges did their weird sweep again before engine failure. This time the CEL came on as we were coasting to a stop. CEL was 2 instances of P1391,CMP or CKP Signal Intermittent Condition. Cleared the code and sat on the side of the road for a good 5 minutes trying to start it. It finally started after an extended crank and we drove home.


I did a bit of searching and decided to replace the camshaft position sensor.



9/7 Cam sensor replacement

I replaced the cam sensor, took it for a bunch of test drives with multiple ignition cycles, no problems. Went to Wegman's, it sat for about an hour while we shopped, then it wouldn’t start. This was the first and only time it wouldn’t start after sitting; the other 2 failures were while we were driving. After 3 attempts to start it, I used a screwdriver and checked pressure at the fuel rail by pressing in the pintle valve, and there was pressure (I didn't have a fuel gauge to check the actual pressure). After 2 more attempts to start, I tapped on the new cam sensor while my fiancé cranked the engine, and it started.

At this point I assumed it was a faulty replacement sensor, so I swapped it for another. Did a few test drives with several ignition cycles, no problems.


9/8 Katie drove to work, no problem

9/9 3rd occurrence:

Katie got about a mile down the road and the engine shut off, this time with the same gauge sweep. However, right before it stalled the CEL came on, for a small evap leak. This is ongoing and I don’t believe it to be related. After 2 attempts, she was able to drive it back home.

Today I did some more research, and ended up checking the timing of the cam sensor for possible slop in timing chain, but my timing is right on using the “toothpick” method (aligning the 2 holes in the cam sensor and housing when cyl 1 is at TDC)


I'm thinking I need to replace that AZ crank sensor with a Mopar one, but before I do, does anyone have any other ideas?


If you've made it all the way through this post, thank you for your time.

Have you tested the CPS (cam position sensor)?

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

Edit: Sorry, that's a link to test the crank position sensor. You could do it to be sure that's not what it is though.

I found this link to test the cam position sensor:

http://www.fixjeeps.com/camshaft-position-sensor.html

Also, if you verify one or both of these are faulty, try and replace with OEM electronics. They typically have a much longer life-cycle, reliability and more resistant to thermal failure which is what it sounds like you're experiencing, hence the reason it runs ok for a little bit then acts up.

I was leaning towards replacing the crappy crank sensor that's in there, I just needed the push to pull the trigger without being able to verify exactly what's causing this. I did test the crank sensor between terminals B&C and it passed, but since it's an intermittent problem that really doesn't mean much. Thanks to Amazon and my points balance it'll only cost me $35, which takes the sting out of throwing parts at it. Thanks for the input.

Your signature makes me chuckle. In this situation I didn't have a choice but to use the AZ sensor when it failed on the trail, but this time around it will definitely be a Mopar sensor.

My XJ wouldn't start because the distributor connection tips reached a point of corrosion and wouldn't start so I replaced the distributor cap and spark plug wires and it worked fine and takes half the time to turn on than before (when it would start but it would take about 7 seconds, still too long)

Crappy parts will give crappy results. I only buy Standard brand or OEM sensors and switches. Rockauto has them, or copy and paste the part number into Amazon.

I have distributorless ignition, but thanks. My plugs are in good condition and I can't imagine it's my coil.

You're quite welcome Jayne. I understand that sometimes ya gotta do what ya gotta do.

Let us know how it works out.

94 grand Cherokee limited stalls replaced crankshaft sensor cam sensor what else....please help thanks in advance

Check your TPS (throttle position sensor) and IAC (idle air control) valve. Also check for vacuum leaks.

Engine dies while driving
 

Well that's what I thought too but when I opened up the cap, there was a small dark silver bead like thingy that had a medium sized diameter (approx) and it didn't fit anywhere which was quite odd. Plus corroded connectors on the cap meant that the metal in the wires touching the corroded connecters was also corroded. After I replaced both the cap and the wires, the car starts in 2 seconds rather than 4 and idles at least 4x more smoothly and the idle stays at a constant 400(ish) rpm instead of the 750 rpm that it idled at before.

Progress report: looks like the Mopar crank sensor took care of the stalling issue. Almost a week of driving with no more problems. Hope this helps anyone out with future diag issues.

That's a good point. Might be why my jeep stalled when shifting from reverse to drive the other day. And when I had just turned it on, and when I'm at a stop light, the acceleration might lag a little bit and then it lurches forward. It's odd. But I need new tires though really badly

I had this same exact problem with my 2000 Jeep Grand Cherokee AND again in my 2003 Grand Cherokee. I took it into a Jeep dealer and they raked me over coals and eventually I had paid a couple thousand bucks for them to replace things that weren't the problem. My Jeep kept dying. Eventually, last, they replaced the CPU (or PCM I can't remember what it's called). It is basically the computer of the Jeep. It is about the size of a large piece of bread and it's silver metal. My Jeep no longer dies, problem solved. The CPU I purchased was a used one off another Jeep from a scrap yard and it's still going strong 6 years later. So if I was you, and I was having this exact problem, I would START with replacing the PCM computer FIRST. Good luck.

Yeah I luckily am friends with a mechanic who gave me his ecu (that's what you're talking about) from his xj and now my jeep runs great. Apparently the ecu is starting to go out on Cherokees for people