Woodfrog

1998 Cherokee Sport.

Problem started about 1 month ago and is getting more frequent. No codes come up on scan.

Tested Fuel Pump and shows a steady 46 I think it was.

I replaced a couple of blown fuses but no fix. Not wanting to sink a bunch of money into it, but I love to drive it so I'm hoping to get some ideas.

It has 250k miles on it and no AC compressor so the value here is minimal. I just need a 4wd before winter and as I said I love this thing.

Somebody mentioned in a previous thread a "peddle" beneath the battery? Others talk about the screws in the pcm as possible fixes. Any other cheap fix ideas to try?

Thanks

Jeepster2

There is a cable that we had to replace on our 1989 Jeep because it would shut off I believe it was called the fly wheel sensor, can't exactly remember right now, I'll look it up later and get back to you. Ours was worn and melted, you could see it if you looked up under the drivers wheel well back towards the fire wall from beneath the Jeep.

Ralph77

Any chance your symptoms are something like these:

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

BillyBoy

Park it with the hood open.
start it. Put on a leather glove.
start wiggling wires and connections.
start with the big harness across the top firewall.
shake the heck out of them.
when it stops, you found your bad wires.
that's what caused the fuses to blow also.

4.3L XJ

The most likely culprit is the crank position sensor. No one ever changes them as a preventative measure. But they will fail intermittently when they wear out and can have a number of symptoms. One of them is shut downs with a restart afterwards

outersketcher

And yet another possibility is what happened to me. My interior air blower motor had gone bad. And the extra draw of current needed to make the fan turn on its ruined bearings was heating up and damaging the wiring in my ignition switch. Burning out the electronics and shutting off all power to the Xj at random moments while driving.

It was especially fun to have the XJ shut down while going 75 mph on the freeway. Lots and lots of fun trying to wrestle that jeep, with no power steering, and no running engine, to the side of the freeway, with one hand... while responding to the angry honks from fellow drivers with your other hand.

heres the thread.

BlueRidgeMark

Take the advice in the last three posts, in order, and I'd say you have about a 97% chance of solving your problem.

s346k

mine did that when the ignition coil was failing. it shut off several times over the course of 3 months and one time it would not restart. so i had the joy of diagnosing the issue and repairing it in a bp gas station parking lot with my 10 year old daughter passing tools down and cranking over the engine while i was using the test light. surprisingly the most impressive thing was the fact she was so helpful.

PatHenry

Agree

Flywheel sensor is Crankshaft position sensor (CPS). These can fail in general and can have issues with wiring (often the wire comes off the mounting points and hits the hot exhaust pipes.) Mopar brand replacement is advised as these Jeeps are picky about this sensor.
On a side note, I personally tend to think the frequent CPS failures are common to automatics but not manuals. I've lived through 700k on 3 different manual transmission Jeeps without a single CPS failure.

jordan96xj

I wonder if that is a temperature thing. Given the location of the sensor. Magnets, epoxy, and wires don't survive long in hot temperatures, and that area right at the top of the trans tunnel on top of the bell housing is one of the hottest areas on the vehicle when at normal operating temperature. Not to mention the occasional additional heat due to towing or climbing hills, etc.

Ralph77

That is what I believe my problem with the CPS was. As soon as it got up to operating temperature it would just stall. But restart immediately. From then on it got progressively worse though.

PatHenry

Yeah, I have to think it's more heat with the automatics than the manuals. I don't know why the AT runs so much hotter, but the fact that an AT needs cooling via the radiator and a MT does not - coupled with the fact that the CPS is subject to thermal failure supports the theory.

4.3L XJ

It is just a magnetic switch. 100K miles times 2.5K times 60 minutes and it wears out. Heat or no heat. They just need to be changed at the most every 100K, preferably every 50K

PatHenry

My Dad's 94 XJ - AX15 - went 400k with the original CPS in it the day it was hauled away. The entire drivetrain still ran perfectly, the body had just rusted out.
My 00 TJ - NV3550 - went 300k with the original CPS. I sold it to a buddy and after sitting for 2 years he drove it home despite the bad transmission.

So is it that my family is just --super-- lucky, or is it possible that the manual transmission models have something or lack something as compared to the automatic models that allows the CPS an extended lifespan. I happen to think it's the latter - but who knows, I'm just throwing it out there.

outersketcher

400k.... and.. and.. 300k..

wow..