Jeep won't start while engine is hot
 

I have a 2001 Jeep Grand Cherokee with the 4.7 engine.

It starts fine but after I drive for a bit then stop and turn the jeep off, it won't start while the engine is still hot. It tries to crank, the engine turns over but it will never start. Once it cools down it starts.

I've changed the crack shaft sensor and it still does it.

I was told that it could be the PCM? Is that possible? The guy told me that he had a jeep that used to happen to and he had a can of contact cleaner that he would spray on it and it would cool it down enough to start.

Starter? Solenoid?

Ideas?

Thanks!

My first guess is a fuel pressure/vapor lock issue. Next time it won't start cycle the key on for a couple seconds, off then on for a couple seconds, a couple times, then try to start. When you turn the key to on the pump runs a couple seconds to prime the system then it shuts off till you start cranking, that's why I say to cycle it a few times before trying to crank. If the fuel pressure is bleeding off and the gas boils in the hot fuel rails it can take a few run cycles to clear it.

It could be the PCM, but seems a bit odd that it never just stops working while driving.

If it cranks fine it's not the starter or solenoid.

I tried to cycle the pump several times. It still won't start.

Is it possible that the new crank shaft sensor is bad?

Did you replace the Crank sensor with a Mopar sensor (OEM) or after-market. If after-market then it is very likely NFG, or it will be very soon.

Check connectors (clean, free of corrosion and fully mated "clicked/locked") and the wires (no bare wires or broken crimps).

There's that SJ again!

It's an after market sensor.
I've checked all the connections up top but not underneath like on the starter etc.... I'll check there too.

Won't run when hot
 

Check the the map sensor. I replaced all the other sensors and stumbled on the MAP sensor being bad. Be careful with the wire connectors are fragile.