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Amedee
Amedee, Dodge Technician
Category: Dodge
Satisfied Customers: 25840
Experience:  ASE certified tech advanced level specialist. Wisconsin certified emissions state inspector
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2001 Dodge RAM 1500 4x4: that spits and sputters when towing

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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?


AMEDEE :

Hello and welcome to Just Answer! My name is XXXXX XXXXX I can assist you with your question.

AMEDEE :

Please allow me to ask a few questions in order to better help resolve your concern.

AMEDEE :

Are you saying that the distributor was replaced?

Customer:

No the distributor cap, rotor, cam position sensor, plugs and wires - please note this truck runs great when not towing.

AMEDEE :

Thank you for clearing that up

AMEDEE :

The cam sensor is located inside the distributor

AMEDEE :

Are you saying that the distributor was removed and the sensor inside was replaced

Customer:

under the rotor yes

AMEDEE :

and then the distributor was then re installed?

Customer:

no in the 2001 5.2 (318) its under the rotor and serviceable without removing and replacing the distributor

AMEDEE :

And this sensor was replaced right?

Customer:

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

AMEDEE :

Thank you for that information

AMEDEE :

Is this code present in the computer when the engine runs good (not towing anything)?

Customer:

no code only reappears intermittently when misfiring(spitting and sputtering) when towing

AMEDEE :

Got it! Thanks!

Customer:

one other note this does not seem to happen in cooler outside temperatures (doesn't happen in the winter)

AMEDEE :

Excellent!

AMEDEE :

Thanks for the detail

Customer:

np

AMEDEE :

Were these signals from these two sensors checked?

AMEDEE :

If so, how?

Customer:

are you talking about the o2 sensors?

AMEDEE :

no

AMEDEE :

cam and crank sensors

Customer:

I did not

Customer:

no testing equip just replaced

AMEDEE :

Ok, how do you plan on diagnosing this code and running issue then?

Customer:

good question - since this only happens while towing - how can you troubleshoot? If I stop unhook trailer - issue is gone

Customer:

I had ase mech ride with while his computer was connected - he came up with replace both 02 sensors

AMEDEE :

And do you know what lead him to this conclusion?

Customer:

rich indication when actually lean and vice versa

AMEDEE :

hhmm..

AMEDEE :

ok

AMEDEE :

Well, I have never heard of bad o2 sensors causing a P1391 code

AMEDEE :

I am not saying that your o2 sensors are good, I am just saying..

Customer:

one quick note - if I stop shut off engine for 10-15 minutes and restart runs fine

Customer:

even if I continue spitting and sputtering down road it does get better eventually

AMEDEE :

Was the distributor sync checked?

Customer:

can't say that it was

AMEDEE :

This would be the first thing that needs to be checked WHEN the problem is acting up

AMEDEE :

It can be checked using a scan tool

AMEDEE :

It should be at 0 degrees

AMEDEE :

plus or minus two degrees

Customer:

I have a craftsman scan tool I don't think it has that capability

AMEDEE :

I agree

AMEDEE :

P1391-INTERMITTENT LOSS OF CMP OR CKP
When Monitored: Engine running or cranking.
Set Condition: When the failure counter reaches 20 for 2 consecutive trips.
POSSIBLE CAUSES
CMP SENSOR OUT OF SYNC
DAMAGED TONE WHEEL/FLEX PLATE (CRANKSHAFT)
DAMAGED TONE WHEEL/PULSE RING (CAMSHAFT)
IRREGULAR LAB SCOPE PATTERN OF CMP SIGNAL
INTERMITTENT CKP SIGNAL LOSS WHEN WIRING IS WIGGLED
IRREGULAR LAB SCOPE PATTERN OF CKP SIGNAL
WIRING HARNESS INTERMITTENT
INTERMITTENT CMP SIGNAL LOSS WHEN WIRING IS WIGGLED
SENSOR CONNECTOR/WIRING
SENSOR CONNECTOR/WIRING
CAMSHAFT POSITION SENSOR
CKP SENSOR CONNECTOR/WIRING
CRANKSHAFT POSITION SENSOR

Customer:

shouldn't this occur all times not with respect to towing?

AMEDEE :

no

Customer:

is it possible for the crankshaft end play to be out of tolerance causing movement when under heavy load?

AMEDEE :

It sure could! but I have never come across that causing this code.

Customer:

honestly the code doesn't always show when spitting and sputtering

AMEDEE :

Chances are it wont

Customer:

137k miles on this truck

AMEDEE :

yeah, that is a lot

AMEDEE :

Your best bet would be to check the distributor sync when this happens.

Customer:

for a 318 that should be just broken in

AMEDEE :

and if needed, use a lab scope to check these signals when the engine runs rough

Customer:

ok I will do this, thank you

AMEDEE :

Your welcome. Are you happy with my assistance today?

Customer:

yes

AMEDEE :

Excellent! I am glad I can help!

AMEDEE :

One thing before you go

AMEDEE :

I just ask that you please rate my answer as "excellent service" for assisting you today

Customer:

ok will do

AMEDEE :

You should see the rating system towards the bottom of the page

AMEDEE :

It has been a pleasure working with you today

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