Stalling 2001

A couple weeks ago I was out in the Salome Wilderness area of Arizona, driving along a washboard road when all of a sudden my engine just stopped. The radio stayed on and the A/C fan was still blowing, but the engine just shut down. Before I even came to a stop I put it in neutral and tried to restart it, but I got nothing. I turned the Jeep completely off and tried to start it again, and it would turn over, but wouldn't start. I had fuel, the battery was fine, belts/hoses were all in tact, nothing was leaking and the oil level/temp was good. New spark plugs about two months ago, too. I popped the fuse box open and all were in good shape and plugged in. After about 15 minutes of wondering if my fuel pump had failed me, I turned the key over and VROOM! It started right up.

I high tailed it home because I was out wandering alone and the AZ desert isn't a good place to be stranded. The Jeep has been fine ever since, until today. It did the same thing as I pulled into work. It just died. Same symptoms, but this time I was on pavement. After a little wait, it started up again.

What is going on with my Jeep?! Do fuel pumps fail slowly?

84k miles
4.0 I6
NP242
Everything stock. And I mean EVERYTHING.

Highest liklihood, and not easy to diagnose if it is intermittant, is the crank position sensor (CKP). This is down on the bell housing at the back of the engine and signals spark plugs and fuel injectors. If you search, there are many threads on this. Try carrying a bottle of water with you and pour it on the sensor next time it fails. Often it will restart and prove to be heat sensitive. Or just replace it and go with the 85% odds. By the way, it also tells the fuel pump to run. It sends the signal to the PCM to make everything happen.

Thanks for the good info, I'll do a search.

The most likely cause of it cranks and cranks but won't start up is the Crank Position Sensor (CPS). CPS failure is very common. The CPS can stop working with no warning or symptoms and the engine will not run or the engine may randomly stall for no apparent reason.

Crank Position Sensors can have intermittent “thermal failure”. This means that the CPS fails when engine gets hot, but works again when it cools back down.

Carry a spare CPS and all the tools to install it or just replace the CPS as a preventative maintenance item and you should be good for another 8 years or so.

Tim_MN said:

The most likely cause of it cranks and cranks but won't start up is the Crank Position Sensor (CPS). CPS failure is very common. The CPS can stop working with no warning or symptoms and the engine will not run or the engine may randomly stall for no apparent reason.

Crank Position Sensors can have intermittent “thermal failure”. This means that the CPS fails when engine gets hot, but works again when it cools back down.

Carry a spare CPS and all the tools to install it or just replace the CPS as a preventative maintenance item and you should be good for another 8 years or so.

Click to expand...

CranKshaft Position Sensor
Camshaft Position Sensor

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