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98 Dodge Ram 5.2 missing


tofast4us10
07-14-2010, 06:17 PM
I purchased a 1998 Dodge Ram 1500 2WD Quad Cab 5.2 (318) that had a few bugs that needed to be worked out but got it for a great price. The truck has a miss in the engine. I checked it and the trouble code is P1391 which is a camshaft or crankshaft position sensor problem. I have checked both of these and they checked out ok but I replaced them with new unit's also so I know it isn't them. The truck's previous owner dosen't know much about the condition of the truck either since they purchased it in that condition and never repaired it. Which leads me to my current question. I checked the engine block and all I could find are the casting numbers 530067-14-318-28 but couldn't find anything on the internet about what year the engine is off these, even 2 dealership's I called couldn't help me out.

The truck had had a used auto transmission put in recently before the previous owners purchased it but I can't seem to find anything wrong with the trans so I've kinda eliminated that. However the engine has also been changed, I knew this because the one in it has a disconnected EGR valve. I went online and 98 Dodge Ram's did not receive and egr valve from the factory however 1994-1996's did. I went to the junkyard and got all of the stuff off of a 98' ram to take the egr valve off the engine block and block off the hold hoping that would fix it but it didn't. .

So here's where I am I'm throwing code P1391
1. I've checked (they were good) but replaced the Crankshaft and Camshaft Sensors,
2. Put in new spark plugs, wires, distributor cap, rotor, coil
3. Not the computer b/c it threw the same code with 2 different one's (the computer that I tried is off a '96 ram)

From what I see the 94-97 Rams had a different distributor from the 98-02 could this be what is causing my problem? Assuming that when the engine was changed they kept the old distributor.

Any help would be greatly appriciated.

tofast4us10
07-21-2010, 06:09 AM
I changed the distributor with one off of a 1998 Dodge ram and it's still throwing the code. Any ideas anyone?

Chris Stewart
07-21-2010, 05:52 PM
Have you reset the codes?
What do you think about a possible PCM swap while the prev.owners were chasing the miss?
I'm thinking of your basic tune-up....fuel pressure?

tofast4us10
07-26-2010, 06:16 AM
Yes I've reset the code several times it takes between 2-20 miles for it to come back. I've noticed usually the first time after resetting it it will stay out it's only the second time that it is started after resetting that it goes off, normally within a mile of two.

I took the truck to the local (five-star) Dodge dealership on Friday only to pay them $200 for them to tell me that the problem does exist but that they couldn't figure it out.

I'm thinking maybe the next thing it get a computer and whole engine wiring harness off another 98 Ram and swap that. When I put the 96' pcm it did the exact same thing as the 98 one that's in it but it is a different year so that's not a good comparison.

The Dodge dealership was able to tell me that the pcm in the truck is the one that came in it from the factory.

Could the fuel pressure cause a faulty Crankshaft/Camshaft Position sensor problem? If so maybe I can check that. The unusual thing is that the truck runs pretty well as is.

Chris Stewart
07-26-2010, 10:18 PM
P1391 Intermittent Loss of CMP or CKP.
Loss of the Cam Position Sensor or Crank Position
sensor has occurred. For PL 2.0L

This means it is a momentary loss of signal. Check the wiring connections from the sensor to the computer.
You might also check the grounds on the engine and body.

tofast4us10
07-27-2010, 07:56 AM
That could make sense, I won't have a chance to get back to it until this Friday but when I do I'll check the CKP and CMP wires for continuity and loose connectors to the PCM (I know which pin it is on the pcm for each) and it I don't have good continuity it may mean a break in the wire. I guess in that case I would have to take the cover off and trace the wire through the loom and look for a bad spot correct?

Chris Stewart
07-27-2010, 08:59 PM
I agree with you. Sometimes just dis-connecting and re-connecting a connector establishes a better connection.
The "TPS"/APPS on mine goes intermittent and working the connector a few times is basically good for a year.

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