So this has happened to me four times now. First two times were at Rausch Creek on the trails. The jeep dies randomly with no warning. Each time it takes a couple of minutes before it starts up again. There is plenty of power, all the gauges work and starter. It acts like it's not getting spark or fuel. I can't tell if I hit something while prodding around those few minutes or something cools down. But after about 5 minutes it starts up like nothing happened. The first two times were within a day. The third was over two months later and the last time was about a month after that. I drive it often and it is hard to say what the issue is since it's so random and spread out. I checked the resistor wires near the battery/relays. Played with the wires hoping one would short out at the fuseable links, even played with the fuel wires at the pump and filter, nothing made it idle different. I've read the CPS can cause issues but they seem to die and stay dead. Hoping someone may have had this same issue and fixed it.

 

It does sound like a crank sensor starting to go bad , mine was doing the same thing it die every so often changed the crank sensor and the problem is gone , it hasn't die since I changed the crank sensor . pick a good sensor because it is important that the last and not leave you some where you don't want to be .

 

Thanks. I appreciate it.

 

You are experiencing "thermal" (heat related) failure.

The #1 cause of thermal failure on the 4.0 is the crankshaft position sensor

The #2 cause is the ignition coil. But the crank sensor fails way more often.

Testing can be done but must be done when you are in a no-start condition as testing when the vehicle runs may be within spec and not be of any value.

If you replace the crankshaft position sensor, buy an OEM Mopar Jeep unit as aftermarket crank sensors are very "hit and miss" with a lot of miss.

Good luck and keep us updated!

 

Ordered a Echlin Ignition CPS from Napa. I'm pretty sure the sensor is stock, it's at least over 10 years old since I've never replaced it. Reading online that was the one people recommended to get from Napa if you don't go with a dealer. Should be here tomorrow but won't get it in then with work. I checked the area out, can't wait to not drop a bolt into the bell housing hole. Thinking of taking extra caution and a rag to plug the hole up to help my chances of that not happening.

 

 

Yea ok. OEM/Napa is the what they recommend. Echlin Ignition is Napa's premium brand and what i've read is the sensor that most use to replace the other aftermarket sensors with no fail

 

So apparently there is supposed to be some grommet at the CPS, guess it fell off or was taken off in it's lifetime.

 

I don't know who your "they" is, but it's sure not the knowledgeable people on this board. Mopar, made by NTG/NGK, is the ONLY thing recommended by people who know what they are talking about.

Even quality brands like Bosch are not recommend. Echlin is quality, sure, but it's still not recommended.

I'd use Echlin for anything in any other vehicle, but not with a Jeep. They are known to be very picky, and especially with the CPS.

 

Ok i'll update this thread after I put it in if I find that it didn't help. I'll send you the invoice too!

 

That's on you. You were warned ahead of time by one of the most respected members on this, and other, Cherokee forums.

 

I had to get one from autozone because they were the only one to have it and I needed it right then so I got it it's been working fine and they have a life time warranty . But when I get some money I want to order a Mopar sensor . but for now the autozone one is working fine .

 

Yeah, seems like they usually do work for a while. They just don't last. So in a pinch to get on the road, sure....


But then, there are plenty of "dead out of the box" stories, too. It's a crapshoot.

 

Well if one wants to be so negative i'll send you the issues I run into. Must not of gotten that reach around you were hoping for. I'll keep up to date on this to let everyone know how it goes. If it bites me in the **** that's fine i'll get the Mopar one, I had Napa points and it's right down the street from me.

 

Sensor is in, took about 45 minutes of arm bending to get all swapped out. I cleaned the mounting area before putting the new one on. Overall I would say it's not terrible. Old one was coated in grud. I cleaned up the old one and put it in the box, just in case. But so far so good put about 20 miles on it since the morning running errands and no issues.