2000 Jeep Grand Cherokee 4.0L random stall

[Dominatorstang]

I am trying to figure out what is causing the stall on this Jeep. I say it is random, but honestly so far it happens about 5-10 minutes after cold startup. Then will not restart unless it sits for a few minutes. I have not been able to have it happen to me yet, so I could not do the normal checks while it is not starting. The few times it has happened have been at a stop light or in a drive through. After restart then it has not happened again until after a cool down period.

I am expecting it to be the crank positioning sensor, possibly fuel loss, or the ECM solder joints (not sure 2000 model still had that issue). But I do not want to throw parts at it because it is my daughters car and I want to be confident it is fixed before she is driving it again.

I logged it idling from cold for 10 minutes. Idle was solid for the entire time except around 6m20s it dipped hard into the 400's and caught itself. Fan was not kicking on or anything to cause it. Viewing the log I see the rpm registering and the O2 is showing it stayed lean for a bit, so leaning towards fuel now. If crank sensor, the rpm would go to 0 right, since that would be how it gets rpm. If I can get it to stall in the morning after another cool down and not start then maybe I can figure out more. I do have a fuel pressure gauge hooked up under the hood, but was watching dashboard when the dip happened.

The rpm dip is in the middle of the log. The last few seconds of the log is me shutting it off and restarting.

[kaineoutlaw]

i have had stalling problems w 4,0 crank sensors, even had a new one be faulty and it took me weeks to figure out the new sensor was bad

[Dominatorstang]

Thanks kaineoutlaw, do you have any logs from when the sensor was an issue? It would be interesting to see, I am guessing the rpm would have to show zero even when cranking or quick change to zero or unnaturally erratic in a log right when it causes it to stall.

[Dominatorstang]

Could not capture any issues this morning in the log or on the fuel pressure gauge. I will have to wait a few hours or so with a shop fan blower on the engine to help it cool and then will take it for a drive this time, to try and better recreate the events that trigger it.

[rays04gtx]

back around 2002 the 2000 4.7 Dak, I bought new would do the something similar, but it wouldn't stall , drivw time didn't matter, it could of been a trip around the block or the 33 mile drive to worlk, you would shut it off and it would not start again till an hour later, turned out to be the crank sensor.

[Dominatorstang]

Okay, I feel confident that it has now proven to be the crank sensor. And glad it agrees with what others are sharing from past experience

Drove it around for a while with no issue until 10m36s into the log I am coasting and it just stalls out. I put it in neutral while coasting and crank, but not hitting. Pulled over to the side and cranked, this time it started up just fine and back on the road.

Reviewing log, you can see from the 10m36s on that RPM is at 0 but oil pressure is still good because the transmission is driving the engine. Then I put it in neutral at 10m44s, which has the oil pressure dropping off, speed goes to zero, and idle commanded rpm drops, this is where I am cranking. Then speed comes back, but no RPM registering. Then 11m06s the cranking is registered and starts up fine. I would leave open the possibility of the ECM has an issue to show this in the log too, but most all other sensors are registering fine.