P1391 and the cam sensor

[dodj]

So the CEL came on and the reader says it's a 1391. Cam or crank sensor. So I clear it and go around the block. Didn't come back on until I get the revs up around 3k+.
Back in the driveway I went to unplug the cam sensor to check the connector and it moves around. Like it is really loose. Several turns with my fingers to get the bolt on the hold down clamp finger tight. So I figure I found the problem...but...timing must be somewhat 'off'.
Do you set timing on the 4.0l the same way you would with any engine with a distributor? Timing light or vacuum gage and just turn the sensor like it was a dizzy?

 

[macleanflood]

Depends on the year of your Jeep. Some need aligned with a scan tool.

-Mac

 

[dodj]

2003 4.0l

 

[JKP]

The cam sensor is not used for ignition timing. It is used to time the injectors.

You are going to have to set the engine to TDC and then align the cam sensor.

My 06 uses a different type cam sensor than yours, so I'm not sure what alignment marks yours has, but your FSM is available under resources.

 

[dodj]

OK,thanks, good to know.
What sensor provides feedback for ignition timing? Crank?

 

[JKP]

Yes, crank sensor for ignition timing.

 

[dodj]

To close this out, the clamp holding down the oil pump drive being REALLY loose is what caused the P1391 code to be thrown. After tightening back down and clearing the code I went for a 50 mile drive and the code never came back. Repaired and didn't cost a cent..how many times does that happen?
Bonus...the idle is glass smooth now.

 

[macleanflood]

Well, your luck is mine...wife was telling me about some strange grinding noises on here JK...found the driveshaft loose at the transfer case, one bolt completely out...and it was sitting in the skid plate.

Love it when we get that lucky!

-Mac