Jeep engine troubles (00' Jeep GC)

[cruiseroutfit]

My girlfreinds 2000 Jeep Grand Cherokee (4.7, auto) is having some major issues. Here is the scoop...

Runs/drives great, but suddenly the check engine light will appear and motor will not rev. past ~ 2500 rpms, accordingly the vehicle won't accelerate past ~50 mph. It feels as if it is governed. If you shut the engine off while this is happening, it will not restart. It will crank, and crank, backfire and sputter.... but no start. Let it sit for a couple minutes, and all of a sudden it will fire right up and run/drive just fine.

This has happend four times now in the past couple weeks and I want to get it fixed. I pulled the troublecodes (P0320 & P0725). Both indicate an Ignition/Distributor speed input circuit malfunction. The books recomend replacing the crankshaft position sensor, etc.

Anyone have any ideas before I start throwing money at sensors, etc.

 

[Hickey]

It sounds like it is in going in and out of "Limp" mode. Definitely points to a timing signal problem. CPS, sounds like and easy one. Is your distributor on backwards?

 

[cruiseroutfit]

It sounds like it is in going in and out of "Limp" mode. Definitely points to a timing signal problem. CPS, sounds like and easy one. Is your distributor on backwards?

My thoughts too... I stopped by AZ to run the scan, the part is only $40 but the vendor is out of stock. I am going to call around tomorrow and hopefully find something here in town.

Any idea why it wouldn't resart once in limp mode? Kindve crazy.

I have been searching online, there is alot of info re: PO320, but nothing to difinative...

Keep the suggestions coming... Anyone on Jeep specialty lists that could cross post this for me?

 

[Milner]

Either Crank PS or cam PS if they have one.... DO NOT get them from any place other than the dealer. I had 3 bad ones out of the box from AZ.
Crank sensor is the most commom problem....Sounds real similar to a problem Durham had with his rig (ran the same motor) and it was the crank sensor....

 

[Brett]

Either Crank PS or cam PS if they have one.... DO NOT get them from any place other than the dealer. I had 3 bad ones out of the box from AZ.
Crank sensor is the most commom problem....Sounds real similar to a problem Durham had with his rig (ran the same motor) and it was the crank sensor....

I'll second the dealer only parts on this. Jeeps are finicky about those sensors.

 

[mbryson]

Either Crank PS or cam PS if they have one.... DO NOT get them from any place other than the dealer. I had 3 bad ones out of the box from AZ.
Crank sensor is the most commom problem....Sounds real similar to a problem Durham had with his rig (ran the same motor) and it was the crank sensor....

I'll third the DEALER ONLY for Jeep ignition parts......

 

[TigerStripe40]

My girlfreinds 2000 Jeep Grand Cherokee (4.7, auto) is having some major issues. Here is the scoop...

Runs/drives great, but suddenly the check engine light will appear and motor will not rev. past ~ 2500 rpms, accordingly the vehicle won't accelerate past ~50 mph. It feels as if it is governed. If you shut the engine off while this is happening, it will not restart. It will crank, and crank, backfire and sputter.... but no start. Let it sit for a couple minutes, and all of a sudden it will fire right up and run/drive just fine.

This has happend four times now in the past couple weeks and I want to get it fixed. I pulled the troublecodes (P0320 & P0725). Both indicate an Ignition/Distributor speed input circuit malfunction. The books recomend replacing the crankshaft position sensor, etc.

Anyone have any ideas before I start throwing money at sensors, etc.

Dude, have her get an 80 series Cruiser!

 

[BBowski82]

The grand doesn't use a distributor does it?? It is a COP (Coil on Plug) motor...and uses the crank position sensor for it's rpm input. The crank position signal return comes in on pin 5 at the pcm (gry/blk wire) verify your wiring is okay from CKP to PCM, if alls good replace CKP.