I have a 2001 Dodge Ram 1500 4x4 that runs and drives great when not towing my boat approx. 3500 lbs. When towing after approx. 15-20 minutes it spits, sputters pings and knocks. Essentially no horse power at all. No check engine light normally when this occurs. I have seen p1391 intermittent loss of ckp code. This truck came with a trans cooler from the factory. This appears to be related to temperature related, since I can let it cool down and it runs fine, I have driven when spitting and sputtering forcing it to run and it will get better after a while. I've had this in several shops and been diagnosed and "repaired" I even had a mechanic ride with me, diagnosed the problem to be o2 sensors. I've replaced all ignition system components (crank sensor, ignition pickup, cap, rotor, wires, entire exhaust system including catalytic converter). Still the truck runs great when not towing, but not reliably when towing. Any thoughts?
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Please allow me to ask a few questions in order to better help resolve your concern.
Are you saying that the distributor was replaced?
No the distributor cap, rotor, cam position sensor, plugs and wires - please note this truck runs great when not towing.
Thank you for clearing that up
The cam sensor is located inside the distributor
Are you saying that the distributor was removed and the sensor inside was replaced
under the rotor yes
and then the distributor was then re installed?
no in the 2001 5.2 (318) its under the rotor and serviceable without removing and replacing the distributor
And this sensor was replaced right?
yes - by myself and verified by ASE certified mech - stating the issue was caused by induction caused by the wire wrapped around a spark plug wire - still not the issue
Thank you for that information
Is this code present in the computer when the engine runs good (not towing anything)?
no code only reappears intermittently when misfiring(spitting and sputtering) when towing
Got it! Thanks!
one other note this does not seem to happen in cooler outside temperatures (doesn't happen in the winter)
Thanks for the detail
Were these signals from these two sensors checked?
If so, how?
are you talking about the o2 sensors?
cam and crank sensors
I did not
no testing equip just replaced
Ok, how do you plan on diagnosing this code and running issue then?
good question - since this only happens while towing - how can you troubleshoot? If I stop unhook trailer - issue is gone
I had ase mech ride with while his computer was connected - he came up with replace both 02 sensors
And do you know what lead him to this conclusion?
rich indication when actually lean and vice versa
Well, I have never heard of bad o2 sensors causing a P1391 code
I am not saying that your o2 sensors are good, I am just saying..
one quick note - if I stop shut off engine for 10-15 minutes and restart runs fine
even if I continue spitting and sputtering down road it does get better eventually
Was the distributor sync checked?
can't say that it was
This would be the first thing that needs to be checked WHEN the problem is acting up
It can be checked using a scan tool
It should be at 0 degrees
plus or minus two degrees
I have a craftsman scan tool I don't think it has that capability
P1391-INTERMITTENT LOSS OF CMP OR CKPWhen Monitored: Engine running or cranking.Set Condition: When the failure counter reaches 20 for 2 consecutive trips.POSSIBLE CAUSESCMP SENSOR OUT OF SYNCDAMAGED TONE WHEEL/FLEX PLATE (CRANKSHAFT)DAMAGED TONE WHEEL/PULSE RING (CAMSHAFT)IRREGULAR LAB SCOPE PATTERN OF CMP SIGNALINTERMITTENT CKP SIGNAL LOSS WHEN WIRING IS WIGGLEDIRREGULAR LAB SCOPE PATTERN OF CKP SIGNALWIRING HARNESS INTERMITTENTINTERMITTENT CMP SIGNAL LOSS WHEN WIRING IS WIGGLEDSENSOR CONNECTOR/WIRINGSENSOR CONNECTOR/WIRINGCAMSHAFT POSITION SENSORCKP SENSOR CONNECTOR/WIRINGCRANKSHAFT POSITION SENSOR
shouldn't this occur all times not with respect to towing?
is it possible for the crankshaft end play to be out of tolerance causing movement when under heavy load?
It sure could! but I have never come across that causing this code.
honestly the code doesn't always show when spitting and sputtering
Chances are it wont
137k miles on this truck
yeah, that is a lot
Your best bet would be to check the distributor sync when this happens.
for a 318 that should be just broken in
and if needed, use a lab scope to check these signals when the engine runs rough
ok I will do this, thank you
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