Stalling and not restarting
 

Looking for some help with my 2000 XJ Sport 4x4. On two separate occasions (December 2018 & this past Saturday), it has been stopped at a red light just idling waiting for the green light. It then stumbled for a couple of seconds and then cuts out. Both times when this happened, it won't restart. It cranks over fine but just won't fire. I'm guessing something fuel related. However the kicker is... both times when it happened, I had it towed back to my house and it fired right back up like there was no issue. Both times the span between it dying and then suddenly working again was less than two hours.

Aside from these two stalling occurrences, the Jeep runs/idles/starts fine. No CEL. I'm stumped and looking for advice on what to check that could cause this semi-infrequent stalling & not restarting issue. My wife is refusing to drive it now since we can't trust it. Taking it to a shop doesn't make sense since they would have to probably test it for weeks/months before they could recreate the problem. What do you all think?

An overheated crank sensor would my best guess. Thermal failure. It gets hot, stops working, and the engine shuts off. Once it cools down a bit, it works again.

In my '00 mine was experiencing thermal failure but when it stalled, and it was just like you turned the key off (no sputtering or anything), it would start right back up. At the beginning of the end. Got worse as time went on and I replaced it about a week later when it almost stranded me for real.

I could definitely see a sensor overheating. Both times the stalling happened, it was when running errands in Northern VA stop & go traffic. It hasn't happened when you are doing more driving than sitting. Do you just replace the crank sensor or are there conditions that cause the crank sensor to overheat that need to be addressed?

Ralph77 are you saying the thermal failure that yours was experiencing was the crank sensor too or was it something else?

Yes the crank sensor. Can read about my little experience with it here:

https://www.cherokeeforum.com/f2/cut...riving-241745/

Well, first you test it. They aren't cheap, so just buying one because it is a prime suspect is not the best course of action. I just bought one for my Grand Cherokee, and it was almost $200. You don't want aftermarket sensors on these beasts. Especially not the crank sensor. Parts that fail right out of the box, or within a few weeks or months are legion. Bite the bullet and buy the Mopar. Cry now or cry more later.

As to testing it, that's not difficult if you have a multi-meter. And you should! Plenty of videos on YouTube on how to test it. But.... steer clear of Bleepin' Jeep's video on it. I found it confusing, and I think that might be because he's not correct. Most of his videos are excellent, but I think he missed it on that one. If you read Ralph's thread, you'll find he did the Bleepin' test, and it tested good, but replacing this supposedly good sensor cured his problem. So.... I think Bleep is just wrong on this one.

Here's a pro-tip for replacing it - 30" extension, and a universal joint (helps to tape around the joint so it isn't floppy) and a 2-3" extension beyond the floppy. IIRC, it's an 11 mm bolt. Two of them on a Cherokee. Someone check me on that bolt size, please? I just did my Grand and it's 11 mm. You get to it from underneath and behind. It's on the bell housing on the driver's side. Picture looking forward from behind the transmission, and you'll find the Crank Sensor at about 11 o'clock. Mebbe 10:30.


No need to worry about fixing any heating problems. This is their normal death mode. The cure is replacement.

EDIT TO ADD: I just read over Ralph's thread. It's 11 mm. Thanks for mentioning that detail, Ralph! :cheers:

I read through Ralph's thread and it sounds extremely similar to my issue. To be honest, I wasn't driving the XJ during either of the times that it died. My brother in law the first time and my wife the second time. Neither are car people so their description of what happened when it died is to be taken with a grain of salt.

BlueRidgeMark I just checked pricing and I can get an OEM Mopar sensor for about $85. Not too hateful.

I hear you on testing it but I would think it would test out OK if it wasn't in thermal failure mode. If I was able to test it when it shut down, then I could see it failing the test. I'm not sure about that though - I'm not bad at wrenching but electrical is a weak point for me.

I might have missed it in BludRidgeMark's post but take out the top bolt first and then the lower one. Reverse that for the install. Also I did not do this but shove a little tape in the socket to hold the bolt in there while you are reaching up in there with the extensions to get the bolt started.
Buying the new 11 mm bolts was a waste in my case but I am still not sorry I did.
I suck at electrical. That is why I let a buddy of mine handle the more complicated testing. But a resistance test is easy. Any meter will do this. Even the freebie with the coupon from Harbor Freight.
Almost positive I watched this video to perform it.


He goes over both because older Jeeps are different from newer ones. In an '00 you will be performing the test from underneath though.
Considering how long it takes for your Jeep to restart you might be able to get a better read with the resistance test. Thinking maybe yours is taking a little longer to recover from the thermal failure.
Mine would restart immediately in the beginning. So doing the resistance test gave me a good reading.

Zackly.

This is one of the few parts that the most efficient test is to shoot the parts cannon at it.

Even if this isn't it (which it is) a spare CPS is a near essential anyway.

You could try to duplicate failure conditions by heating the CPS with a heat gun or hair dryer and then testing it, but given the present rarity of the issue a negative test might not be completely diagnostic.

Mine never got so bad that I couldn't make it home, but at the last failure, came pretty close.

You have a point there. Mine was in "I done did all I'm ever gonna do and I ain't doin no mo' nohow" mode, so testing was easy. Intermittent failures are a different ballgame.

I kind of followed a similar logic. When I did mine bottom line it still was a guess. I figured worse case scenario was if did not fix the Jeep I get a new CPS out of the deal. The Jeep had 160K on it at the time and I just assume any part I did not replace myself is original to the Jeep.

Thanks everyone! The Jeep-only mechanic that I use from time to time also came up with the same diagnosis. So I think I am just going to go ahead and replace the CPS and not worry too much about the testing.

Being an intermittent problem, I will still need to drive the Jeep for a while after the CPS replacement to make sure that fixed it and learn to trust it again. If the CPS doesn't fix it, at least I do know that it will restart eventually if it happens again.

Probably CPS, really easy to replace and $40 on Rockauto

I was gonna link Ralph's thread but he's already done so, here is mine
https://www.cherokeeforum.com/f2/96-...n-warm-246772/

So my 1997 Jeep Cherokee has done the same thing, except it turns back on. I’ve looked around and the things I’ve found where a Throttle response sensor (tps) is out and needs to be replaced or a crank sensor, neither of which are over 20$ at autozone