Engine/Transmission (1998.5 - 2002) Engine missing under load...

[cummins_crewcab]

Hello all, I picked up my new 25 foot gooseneck flat bed trailer yesterday with my grandfathers 1999 3500 dually, 24 valve and auto, and all was well on the way down to pick it up. After picking it up and getting into some slight grades, very slight, I would notice that while trying to hold a constant speed, light throttle, the engine would miss about every 20-30 seconds, some big some small. If I got in the throttle it wouldn't do it, if I let off the throttle it wouldn't do it, just at a light throttle condition. This was above about 45 mph that I noticed it. Did it the whole way home. Any ideas?

 

[Gary - K7GLD]

Perhaps uneven pop-off pressure in one or more injectors...

 

[Snow man]

is it possible its the TC unlocking/locking? if not id check fuel pressure first go form there. its sounds like a trans issue to me from how you explain it.

 

[cummins_crewcab]

Originally posted by Snow man

is it possible its the TC unlocking/locking? if not id check fuel pressure first go form there. its sounds like a trans issue to me from how you explain it.

I doubt it, I could easily tell when the TC was locking/unlocking. this was just while crusing, say the cruise set at 55mph and going on level or a very slight grade. This feels identical to the misses I have felt in gas engines over the years.

 

[John - K5AWO]

A "miss" felt rather than a slight rpm change because the a/c compressor is cycling??

 

[cummins_crewcab]

Ended up being a dirty fuel filter, only had about 15k on it since last change, guess he picked up some dirty diesel somewhere...

 

[clem]

Originally posted by cummins_crewcab

Ended up being a dirty fuel filter, only had about 15k on it since last change, guess he picked up some dirty diesel somewhere...

D/C would like to see the Filters changed every 10K

 

[Tcolesanti]

10K for a fuel filter change? Wow, I let mine go for 15-20k. I've never had a fuel pressure drop due to a fuel filter being clogged but, maybe I should change them more often... .....

 

[pfmoale]

Jason,
I believe I have felt the same thing you were talking about, with my rig.
2001 truck, auto trans, with Banks Power Pack, Full instrumentation, plus fuel gauge. Was towing a 7,000 lb travel trailer to Idaho. Everything was fine, no problems.
After a fuel fill up in Burns, OR, I noticed a difference.
Under a load, turning about 2,300 to 2,400 RPM, between 55 to 60 MPH, fuel pressure good, about 10 or so PSI. Temp outside was hot, upper 80's.
After coasting, slowly starting to speed up, could feel the engine miss, something like a gasser would do.
Before my trip, all filters were changed. Primary and secondary fuel filters changed, K&N air filter, cleaned and re-oiled, engine oil changed and new oil filter installed.
Did change out the VP44 I. P. just a little while ago, but never had any problems. Got an upgraded one from Blue Chip Diesel in New Hampshire.
When I have the pedal at WOT, no problems, fuel pressure 8+ PSI, and no missing, everything fine.
Back off to coast, then slightly powering up, could feel the hesitation. No, it was not during, or when the AC was on.
Sometimes AC on, sometimes AC off.
Plugged in the scan tool. No codes came up, says everything fine.

During my trip, my eyes were like a Halibut, one eye on the road, the other on all 5 gauges !

Fuel filters have maybe just over 2,000 miles on them.

Any additional thoughts, from you or others ?

Peter

 

[JR]

It almost sounds like an APPS related issue, you could try to reset yours to see if it helps any.

 

[pfmoale]

JR,

The APPS, in full wording refers to ?

Thanks,

Peter

 

[JR]

Accelerator Pedal Position Sensor, otherwise known as a throtle position sensor (but not on these trucks) These trucks are a fly by wire system, no physical throttle cable hooked from the gas pedal to the injection pump. Sometimes when they start acting up they will produce a "fluttery" type of pedal. This is just a guess at this point since you are having only light symptoms and no check engine light.



To reset the APPS:



Disconnect BOTH of your batteries

Turn your ignition key to run and let the truck set for 30 minutes to an hour

Turn key back to off and reconnect and tighten battery terminals

Turn key to run position (do not start) and depress the accelerator pedal slowly to the floor

Slowly release the pedal back to it's natural position

Turn the key back to off



Then you can start the truck and drive it. What the reset does is allows the APPS to relearn the position of the pedal and its limit.

Now like I said this is mereley a guess and may not do you any good. If it makes a difference for a short period of time and reverts back to its old ways, the APPS sensor is likely on it's way out. Sometimes the reset will not do a bad APPS sensor any good and the only fix is replacement, but I would expect you would have tripped a CEL by that point and time.

Another thing to check (maybe before you do the reset, or while the batteries are disconnected) is all of your battery cables. Make sure they are in good sound condition with no corrosion. Check your ground leads especially. If your batteries are at all suspect have them load tested. These trucks are pretty sensitive to low voltage and bad grounds, so take your time and go through everything.

 

[pfmoale]

JR,

Thanks for the detailed instructions.
Batteries were replaced awhile ago, new Interstate ones. Replaced by a shop I know, AND trust. I know, corrosion can start at any time, so one never knows.

I will talk with the shop I use for major repairs, and ask them if they have come across this particular situation before.
These guys speak Diesel, so we will try to narrow it down.

Thanks again.

Peter

 

[JR]

Your welcome, and please respond back with the solution if you find it (or any other questions/problems). There is a bunch of really sharp guys on here, much better than my shade tree skills, and if you are willing and able to work through the problem and keep reporting back with any developments I would be willing to bet someone here will be able to work you through your issues a step at a time.