1998 Dodge Ram CAM position sensor

Tiny
MRSWELL1
  • MEMBER
  • 1998 DODGE RAM
  • V8
  • 4WD
  • MANUAL
  • 160,000 MILES
I have a 1998 dodge ram 318 has been losing power. I have 120-150 pounds of compression in every cylinder. Replaced cap, rotor, wires, both 02 sensors, map sensor, tps, idle control, coil, intake gaskets, fuel pump, crank position sensor because it was and still is throwning a 1391 code. My rear 2 cylinders on both sides are fouled out. I do get a bank one or two (not sure)fault in the fuel system. I still get the 1391 code and have not changed the camshaft position sensor. I have 160, 000 on this motor, did the heads about 40,000 ago. Any idea what is causing the rear 2 on each side to foul out? Going to get cam sensor but what else is there. Has NO power. Also backfires and pings
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Wednesday, November 19th, 2008 AT 11:51 PM

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Tiny
RACEFAN966
  • EXPERT
Ok I would suspect that maybe you have injector problems in those two cylinders. Do you have access to noid lights so you can make sure they are getting the pulse signal? P1391 is a cam sensor code what is saying is that the expected signal disagrees with the actual signal. So what we have here is the cam sensor arguing with the crank sensor. So what you need to do is check for good grounds to both sensors and make sure you are getting 5 volts to both sensors with key on engine off. From there without a scanner that has an oscilloscope or an oscilloscope you can not test yourself any further then that. Now also check that there are no pinched wires between the heads and block and intake and any possible brackets that could cause a short that would make the sensors disagree with each other ok. Let me know how this goes and we will go from there.
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Thursday, November 20th, 2008 AT 9:56 AM
Tiny
MRSWELL1
  • MEMBER
I changed the cam sensor, checked compression, 130 to 150 all the way through. I checked voltage to crank sensor and cam sensor, 5 volts on both. I checked ohms on all injectors and 12.2 on each. I also turned it over to see if they were spraying and they are. It pops and backfires and idle getting worse. Could my computer be shot? I see that it has some writing on it that it has been re-programmed at some point. I am second owner. Could it be timing chain? I think not because it fouls the rear 2 on each side. If timing chain would fould all of them? Should I get it to dodge and put it on there scope? Maybe the pickup on the flywheel for the crank sensor has a problem? I am lost HELP
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Friday, November 21st, 2008 AT 1:12 AM
Tiny
RACEFAN966
  • EXPERT
With everything you are telling me it is pointing to the crank sensor. That is what he code is about it is saying that between the cam and crank sensor that what they should be telling the computer that one is not. There is a long test procedure if you would like to go throught it that is find let me know to get you test tc-40. Thanks
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Friday, November 21st, 2008 AT 10:00 PM

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