Chad18ge

Hello, I'm new to the forum and hoping to get some guidance from experienced XJ owners.

I have a 2001 Cherokee Sport that I bought in 2012 w/96000 miles and overall above average, good condition. About a year ago I started having sporadic crank/no start and engine dying while driving. It didn't always result in an engine light, but when it did a trip to the auto parts store revealed a crankshaft or camshaft sensor error (can't remember the code number). I replaced both with Autozone parts and the problem was back within a month. Further research suggested to only use Mopar OEM replacements. I replaced both with OEM parts. After about 6 months or so, the problem is back again. I don't drive the jeep a lot and when I do the problem is random. A good example is about 3 weeks ago I drove it to work on a snowy/icy morning with no issues (about 65 miles round trip). The next day I drove it to pick up a new dishwasher (about a 50 mile round trip). The following day I drove it across town (about a 6 mile round trip) and didn't think I was going to make it home - it died twice. Last week I drove it on a 5-10 mile trip and about an hour after I got home it wouldn't start, thankfully parked in my garage. I tried again a couple hours later and it fired right up.

All of my research seems to point back to a faulty crankshaft sensor... Thermal failure doesn't seem to be a culprit since it seems to do worse on short trips. I've cleaned the connector and checked the wiring, everything appears to be OK. I did try checking the output AC current but didn't get anything with my multimeter (not sure I was doing it right or if it's even possible on this year/model as I was following a procedure for an older year)

My biggest dilemma is that my son will be 16 this year and I'd like for this jeep to be his first ride. It has 143,000 and it's in good shape.

I've read about different cps mods and even considered the Hesco relocation kit. Does modifying the mounting bracket to get the sensor closer to the crankshaft disc work on a 2001? Is the relocation kit worth it and will it fix the issue?

Thanks for your help!

gvnc

Huh, I also have a 2001. It mysteriously died a couple times one day, I replaced the crankshaft position sensor with a napa part, and it hasn't recurred. You might watch this vid: It helped me test my cps. That should at least tell you about that part. Since you've already replaced twice (and with OEM), you might need to start looking for other electrical gremlins.
How do your grounds and battery terminals look?

Turbo X_J

OBDII codes indicate an issue with a circuit, not necessarily to pinpoint a faulty component. Component testing is carried out separately. Check the wiring and connectors carefully for damage/corrosion before replacing anything else.

Chad18ge

Thanks guys. I did see that video but I was reluctant to pierce the shielding to test current. Looks like that may be the only way to do it on the type I have.

Battery terminals look good. Ground to chassis (inside engine bay) looks good but maybe there are others to check.?.

If voltage output is low I've seen other posts that suggest drilling the cps mount holes to get the sensor closer to the crank disc. At least one said this wouldn't add any benefit to the newer style sensor. Can anyone confirm?

gvnc

Can't help you with your last question. Made any progress with this? Have you had the battery tested recently?
Have you seen this thread?
https://www.cherokeeforum.com/f2/cra...problem-68656/

There are additional ground points to check and clean up in the engine bay, one is on the passenger side of the engine block, might be worth making sure the starter isn't gunked up with oil from the filter. Maybe someone else will remember others.

Chad18ge

I'm going to work on it this weekend. I had an idea to use jumper wires between the cps harness and connector rather than pierce the shielding to test voltage output. I also plan to check and clean up the grounds, if needed.

Thanks again for the responses. I'll post an update after I complete the items listed above.

Cummins93

A while back just for fun I bought the cheapest CPS I could find. It was about 12 bucks shipped to my door from Taiwan. I warmed it up moved it over about half an inch for some increased timing and tossed it in. Don't always believe that the fix is mopar parts. With that mentioned I urge you to reinspect your CPS wiring, remove your grounds and clean/replace them.

Chad18ge

It's a cold day in south central Ohio. My little garage heater was not up to the task although I left it on and stood in front of it when checking my notes. Before you call me a wuss, let me say that I ran 5 miles outside before starting on the Jeep. Still, running generates more body heat than laying on a cold garage floor!

Ok, so my CPS resistance test was good and output voltage was .4 - .6. Everything I've read about output voltage says 0.5-0.8 is good. Maybe I'm slightly low but unless there's an intermittent cps failure for some reason, it appears to be ok. The wires and connectors look good. The only thing I found is there's a wire/cable keeper located near the connector for the cps and my wires weren't in it. They are now but the connector seems pretty robust and even out of the keeper there's not much excess to allow for vibration to be an issue.

I only visually checked the grounds. Battery v = 11.76. From what I'm reading, it seems like I should probably disconnect the grounds, clean, and reinstall. That'll be a project for another day.

I will mention something that one of the links above reminded me of. A couple weeks ago i drove the jeep on short trip to Walmart and the power door locks didn't work. I don't have keyless so it's a habit to hit the switch to lock the doors - and to unlock after opening the driver door. I just dismissed it as another casualty of old age but when I got home they worked and they've worked since. Not sure if the door locks could be related to the random crank/no start issue but I guess it's possible if it's something electrical.

moparado

FWIW,
I seen somewhere maybe probably on this forum that some after market crank sensors have larger out of spec. dia. pins which can spread the sockets on the mating connector to cause intermittent random issues. One more reason to only go with genuine Mopar components. Check the female sockets on the connector to see if they've been spread out causing an intermittent connection. Sometimes with a dental pick you can squeeze those sockets back for a firmer electrical contact.

Resistance and/or voltage tests on an intermittent problem can be next to useless IMO. If you're extremely lucky the component will be in the failure mode which is highly unlikely maybe by wiggling connectors or wiring.
If you traced the wiring continuity from the CPS to where ever its going and by wiggling the wiring and it looks good then you're probably up the against the wall.....try changing out the CPS connector with a new Mopar one. Only a few wires need to be spliced.

My '94 xj experienced random engine stalls out of no where. Let all cool off and the engine started again. Yep, a flaky CPS.

My current 2000 xj ran just fine even when i parked it in my barn for a few months storage. When i tried to start it again months later, crank no start. Yep a bad CPS again.

Chad18ge

I don't disagree about testing components with intermittent issues. The resistance was likely a waste, but I had the thing apart and the tools right there. The AC current test was more for my own piece of mind to confirm that the output is at least right when it is working - but, you're right, that's not worth much when it's not working or if/when it decides to check out for good.

Chad18ge

I'm resurrecting a dead thread with a long-winded, positive update...

Since my last post - almost 4 months ago - my xj kept getting worse. I tried removing the CPS and drilling the top mounting hole with no change. After a few weeks of sporadic stalling and hot no-starts, I bought a new MOPAR CPS and installed. I actually drove it a couple days without issue but then it returned, still very random and, thankfully, never leaving me stranded.

My daughter and I are training for a 200 mile bike ride later this month and I've been driving the Jeep more since I have a nice trailer hitch bike rack. We hit the nearest drive-thru for a cold drink after almost every ride and the Jeep didn't like it one bit! If there was any drive-thru traffic at all, it'd stall out. If I made it through, it'd stall at the next stop. This was happening within 5-10 minutes of a cold start. I started thinking maybe heat soak was an issue as it definitely seemed worse with the engine running but not moving or if I started within a few minutes of turning the engine off. I added hood spacers. No change. Added insulation below and around the injectors (yes, I know this is a VERY subjective topic). No change... Throughout this process I got an engine light and had it scanned. I don't remember the number but it had to do with injector #5. I ended up replacing the connector for this injector - which I probably broke when I removed the injectors to add insulation

I was actually planning an e-fan mod or adding a fan but I'm not very comfortable messing with wiring so I held off. A couple weeks ago we decided to try biking in a new area that required driving through heavier traffic. This was the closest I came to getting stranded. It died multiple times on the way there. That didn't stop me from attempting a drive-thru stop on the way home and I almost had to push it away from a Wendy's window. It died again about 2 miles from home and I thought we were going to have to ride the bikes. It finally started and I got it home. I asked a co-worker (that's a way better mechanic than I am) to recommend a cheap code scanner and he offered to loan me his. I ran a scan and got one code, P0108. As usual, there's a lot of conflicting info on the web so I decided to just buy a MOPAR MAP sensor - at least it's easy to change, especially compared to the CPS!

I replaced the MAP Saturday morning and drove the Jeep all weekend without issue - including the same route that gave me fits a couple weeks ago, and a trip to the airport yesterday to pick up my daughter in stop & go traffic for several minutes. I'm going to drive it this week but I feel better about it now than I have in a long time. Fingers crossed...

jordan96xj

These follow-ups do get read! So thanks for posting it.