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-   -   Crankshaft Position Sensor or Camshaft Position Sensor? (http://www.jeepforum.com/forum/f9/crankshaft-position-sensor-camshaft-position-sensor-157018/)

TennesseeTJ 04-26-2005 09:57 AM

Crankshaft Position Sensor or Camshaft Position Sensor?
 
Hey all...

My 98 TJ 4.0 with manual trans has been experiencing random loss of power for a year. It sputters, rpms plummet, it sometimes catches itself before it completely dies, other times it shuts down totally. Occasionally it is difficult to restart. This occurs totally randomly, on accelleration, idle, highway speed, whenever.

Yesterday, it FINALLY gave me a diagnostic code:
P1391 - Camshaft Or Crankshaft Position Sensor Intermittent Loss
From the symptoms, that sounds corrent. But which should I replace? :confused: Is one or the other known to be trouble on these Jeeps? Any insight would be greatly appreciated!

-Erik

Jerry Bransford 04-26-2005 09:59 AM

The crankshaft position sensor is noted for more problems than the camshaft position sensor is.

Stu Olson 04-26-2005 10:27 AM

x2 for sure ;)

joeyt17 04-26-2005 11:02 AM

My crankshaft position sensor went out and caused the same problems as you are currently getting. I didn't even get an engine code for it until several days after all the problems started occuring.

changed it out and no problems since

James D. McGinn 10-15-2005 06:12 AM

I changed both the camshaft and crankshaft position sensors on my 98 TJ with 2.5 and 5 speed, and the cel is still on, and it still reads code 1391, even though i have zeroed out the codes several times; however, the engine does run well. Anyone give me any ideas? thank you.

JV96XJ 12-10-2005 08:31 PM

Quote:

Originally Posted by James D. McGinn
I changed both the camshaft and crankshaft position sensors on my 98 TJ with 2.5 and 5 speed, and the cel is still on, and it still reads code 1391, even though i have zeroed out the codes several times; however, the engine does run well. Anyone give me any ideas? thank you.


I have the same situation on my '96 XJ. Replaced both sensors, and the CEL still comes on....Have you resolved your probelm?

Scott_98TJ 12-11-2005 06:58 AM

Well they both talk to the PCM so that's an obvious common link. They also share some wiring on the sensor return and feed from the ignition cicuits. With a wiring diagram you could check all the connections fairly easily.

LadyJeep 12-11-2005 07:30 AM

I had the same problem with my 98 auto 4.0L. It finally did die (wouldn't turn over) out in the desert. Ended up being the CPS.

al666 12-11-2005 09:18 AM

I have the same code on my jeep, been trying to figure it out for 4 months replacing the sensors didnt help could be wireing but im just bringing it to jeep to fix good luck though :brickwall

MCanavan 12-11-2005 09:33 AM

I had the same problem and replaced the crankshaft sensor but still no luck. I took it to a mechanic and it turns out that it was the oxygen sensor (wasn't giving out a code though).

98JEEPTJ 12-11-2005 01:12 PM

I was told by one of the mechanics that the engine wouldn't run at all if the Drive shaft sensor or the crank position sensor wasn't working. That they don't partially work they work or they don't...They both sense a magnetic field disruption which is sent to the computer to tell it where the cam is or the drive shaft. if there is no disruption at all (failed sensor) then the computer wont start the firing sequence of the injectors...

Anybody absolutely know for sure???

Scott_98TJ 12-21-2005 04:43 AM

Quote:

Originally Posted by 98JEEPTJ
I was told by one of the mechanics that the engine wouldn't run at all if the Drive shaft sensor or the crank position sensor wasn't working. That they don't partially work they work or they don't...They both sense a magnetic field disruption which is sent to the computer to tell it where the cam is or the drive shaft. if there is no disruption at all (failed sensor) then the computer wont start the firing sequence of the injectors...
Anybody absolutely know for sure???

As a sensor starts going bad, or the connection has high resistance, it can and will cause flaky problems. If it randomly looses signal, you will get stalling, bucking, hesitations etc. rather than and on/off scenario that you get with a good or failed sensor. In a perfect world he's right, but how often does that happen with Jeeps?

SierraNev 04-16-2010 10:39 PM

:confused:Hey ya'll I am having intermittent issues with my Jeep stalling while driving after a few minutes or at idle speed and after warm up. The codes for pcm not getting signal from cps/cpk "crankshaft positioning sensor" came up. So now that I've gotten that far how the heck do you get to the bugger, take the tire and inner tire panel off or drop the trany? I got a chilten with microscopic pic's and a fellow said I would need a pully puller, I think I can handle it with a lil direction. How bout it fellow Jeepers, a brotha could use some help, its our only car right now. 99 Jeep Grand Cherokee Limited 4.7L

nojeeps 01-20-2011 11:12 AM

The crank sensor is on the lower passenger side of the engine block under the vehicle. The cam sensor is at the front of the passenger cylinder head on the bottom of the head itself.

mdm 01-20-2011 11:20 AM

Quote:

Originally Posted by SierraNev (Post 9299604)
:confused:Hey ya'll I am having intermittent issues with my Jeep stalling while driving after a few minutes or at idle speed and after warm up. The codes for pcm not getting signal from cps/cpk "crankshaft positioning sensor" came up. So now that I've gotten that far how the heck do you get to the bugger, take the tire and inner tire panel off or drop the trany? I got a chilten with microscopic pic's and a fellow said I would need a pully puller, I think I can handle it with a lil direction. How bout it fellow Jeepers, a brotha could use some help, its our only car right now. 99 Jeep Grand Cherokee Limited 4.7L

This is a TJ forum which deals mostly with 2.5 and 4.0L engines.


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