2005 Dakota 4.7 running on 3 cylinders
I'm at a loss on this one. I have quite a bit of mechanic experience but that was pre-computer. I also have an electronic background.
2002 Dakota Sport, Crew Cab, 4x4. 4.7
Truck was running great after an engine swap (reman long block). I had a mechanic do the swap.
Still in the break-in period. My wife stopped somewhere, when she started it back up the engine was running rough and would not idle.
Fresh fuel, good fuel pressure.
Replaced injectors.
Performed smoke test on intake. No leaks found.
Unplugging coils it appears that cylinders 1, 2, 3, 5 and 6 are not firing (or are firing at the wrong time)
coil on plug and plugs were replaced during the swap.
Scanner indicated that PCM wasn't detecting the misfires, pointing to crank sensor or possibly PCM.
P1391 indicates loss of communication between PCM and crank or cam position sensor.
Replaced cam and crankshaft sensors. No change.
Checked continuity on sensor wiring (sensors to PCM). Continuity good.
Unplugged crank sensor and engine died.
Unplugged cam sensor, no change.
Replaced PCM.
Latest fault codes are P0351, P0500, P1391
My wife wants her baby back but it's costing a small fortune.
I would greatly appreciate any help!
2002 Dakota Sport, Crew Cab, 4x4. 4.7
Truck was running great after an engine swap (reman long block). I had a mechanic do the swap.
Still in the break-in period. My wife stopped somewhere, when she started it back up the engine was running rough and would not idle.
Fresh fuel, good fuel pressure.
Replaced injectors.
Performed smoke test on intake. No leaks found.
Unplugging coils it appears that cylinders 1, 2, 3, 5 and 6 are not firing (or are firing at the wrong time)
coil on plug and plugs were replaced during the swap.
Scanner indicated that PCM wasn't detecting the misfires, pointing to crank sensor or possibly PCM.
P1391 indicates loss of communication between PCM and crank or cam position sensor.
Replaced cam and crankshaft sensors. No change.
Checked continuity on sensor wiring (sensors to PCM). Continuity good.
Unplugged crank sensor and engine died.
Unplugged cam sensor, no change.
Replaced PCM.
Latest fault codes are P0351, P0500, P1391
My wife wants her baby back but it's costing a small fortune.
I would greatly appreciate any help!
Last edited by duaned; Apr 12, 2025 at 05:45 PM. Reason: wrong model year stated
P1391 - cam/crank sensor communication
The only other thing I can think of trying is to replace the wiring between the PCM and the cam/crank sensors.






