Engine/Transmission (1998.5 - 2002) power then no power

[Dsullenberger]

Just came back from a 3500 mile trip with my 2002 3/4 ton 6sp truck. I'm the original owner and have always taken good care of it. I put a fuel gauge on shortly after I bought the truck. When the lift pump pressure started to drop around 6psi I installed a Fass Dodge direct replacement pump and installed it on the frame. Always have 15 - 16 psi now. Truck has 60,000 miles on it. The problem I'm having is ( not all the time but once in awhile ) Pulling in 6th gear low rpm or 5th at 50-55 the truck acts like there isn't any throttle. If I shift into 4th the truck finally comes alive and away we go. This started at 500 miles into the trip. There hasn't been any fault codes. I changed the fuel filter before we left. I'm thinking it might be the APPS going out or maybe the wastegate on the turbo. If it was the Injection pump or fairly new new lift pump we wouldn't have made it home. When the APPS starts to fail is this what one can expect? Any info will help.

 

[gtwitch]

DS Is it setting any codes??? Sounds a little like a APPS but that should set code. When you did the filter, sure you got all the air out of the primary side of the system? if you have more systoms, Post them.



gtwitch in wyoming

 

[Dsullenberger]

No codes. Always make sure there isn't any air in system after filter change. Loosen the filter cap and turn the key to non start mode several times until diesel fuel is running down the sides of the filter. Through the years only had one problem with air in the system. Was new owner of truck and didn't know what was going on. Had to loosen a high pressure line and let the air out.

 

[Road Dog]

In my case a little air was getting into the fuel. Just enough to cause the occasional P0216 (injector timing fault). Then no power for a few seconds. Downshifting helped but I suspect waiting would work too. Or maybe the pump spins up with the engine and that clears the fault. No check engine light. I guess it needs to fault a few times before the CEL turn on.

 

[Dsullenberger]

Thanks Road Dog. Tomorrow I will change out the fuel filter again and crawl under the truck and check all fittings around the Fass pump. Still don't understand how we could go 3400 miles without a code. Cruising at 65 - 70 pulling a 6000 lb trailer.

 

[VolsFan]

In my experience with a few 2nd gen 24 valve auto trucks, a failing APPS will throw a code,(PO121?) but anythings possible I suppose. Even if the check engine light doesnt come on there may still be a code thrown. On the autos, the truck will just go to idle and then pick back up a few seconds later. Never experienced a dying APPS on a manual, but what you describe sounds like it could be. After a murphys law weekend Ive had so far, I might get to experience it today!

 

[Dsullenberger]

Thanks for the info VolsFan. I changed out the fuel filter again today. Going to put the camper on and try it out. If the problem is still there I'll order a new APPS from Geno's garage for $169. After reading the forum it looks like several people get shafted at the garage when getting charged for APPS replacement. $169 isn't much for a test.

 

[VolsFan]

There have been a lot of write ups on the apps issues on these trucks. Your truck has low miles for it to be failing I think, but it has some years on it. The instructions for installing it are very thorough and easy to understand, you wont have any problem with it. If you do, get on here or call genos. Good luck with it.

 

[HBarlow]

Your problem is likely to be a failing APPS but the way you described the symptoms really doesn't provide sufficient information.

When you experience the symptoms what happens if you push the accelerator pedal to the floor and release it repeatedly? How about in neutral?

If the engine is completely ignoring the accelerator pedal it is most likely an APPS. I replaced five or six APPS modules on my '01 and never set a code.

 

[r1069]

My 2001 6spd did the same thing. Sporadic. When you lose power, push in the clutch and see where your RPM's go. If they go to idle, it could be the throttle position sensor- that's what is was on mine.

 

[Dieseldemon]

When it happens again pull over and take the top off of the filter and check the fuel level in the filter I had one that did the same thing had a restriction in the fuel supply if I ran it hard it would shut down to an idle let it idle a little bit and the power came back and the filter would fill up under idle.