Engine/Transmission (1998.5 - 2002) Strange power problem

[R0b]

Let me start by stating this is my first dodge diesel. I have always had the old 7.3 idi non turbo in my personal trucks.

Now to my problem

My truck will just randomly lose power no smoke no warning just lose power RPM will not go above 2k.
I can get power back by putting it in neutral and ether
(1) let it idle for a few seconds 5-10 then goose it to see if rpm go above 2k if they do put in gear and go.
(2) turn truck off for 5-10 seconds ( makes me nervous going 70 on highway) restart and go.
The guy I got it from told me something like a cam sensor but I can't remember.


Need to learn how to put signature in.
99 ram 3500 DRW 4x4 ex cab 4 door auto 180k miles 4" cat back cat delete

 

[Road Dog]

It sounds like the VP-44 injector pump is going into limp mode. Usually you would get a check engine light and some codes stored in the computer. You can start by reading Blue Chip Diesel's VP-44 diagnostics. Intermittent problems are a pain.

I had a similar problem and found downshifting brought the power back. It was a false fix -- the injector pump computer would reset whether I did anything or not. The VP-44 internal computer would detect some number of faults and go into limp mode. Then it would detect no faults for a few seconds and reset. It took a couple of techs several hours (and $$$) to figure it out -- a loose fuel line connection at the tank let air get sucked in once in a while. Those air bubbles caused a fault as they passed through the pump.

 

[JR]

Could be an APPS sensor but without some more info it's hard to say. Get a good scanner and post up any codes you may have.

 

[R0b]

will need to go to oriley to get it scanned in the morning

i hope its not the vp44 they are expensive my old idi pumps ran about $600 a pop every 100-150k miles so that was not bad

 

[R0b]

okay had it scanned and no codes and no check engine light.
dont know if this helps or not but it will also do it with the cruise controle on but will NOT kick it out of cruise it just puts the peddle to the floor truing to make it go I have to manualy turn cruise off.

 

[JR]

Generic code readers like the parts stores use are hit and miss on retrieving codes. Probably have to find a DRB or a snap on scanner that reads live data to see what it is doing in real time.

Another thing you can try but not guaranteed is an APPS reset. Sometimes it helps short term if an APPS is at fault.

1. Set parking brake
2. Disconnect negative battery cables on both batteries
3. Turn ignition key to run(to drain any remaining capacitors)
4. Let truck sit for 30 minutes( this is the recommended minimum)
5. Return ignition to OFF position
6. Reconnect both batteries and secure, not a timed event
7. Turn key to run position(not start) and depress accelerator pedal slowly all the way to the floor
8. Allow pedal to return to top position slowly
9. Turn ignition switch OFF
10.Release parking brake

If the reset helps for even a short time it's a good indication the APPS is at fault but as mentioned above the best bet is to get a good scanner that reads live data to see what is going on. Without a hard code set it is your best bet.

 

[R0b]

Well I talked to the person I got the truck from and it had the same problem 3 years ago he replaced the vp 44 and it did not help so he had a friend that works on cummins for a living fix it. it was a
sensor so now we are wating on a call back from him on what one it is so i can get it and change the part out. will keep you updated so maby it will help others if they have the same problem.

 

[JR]

I would be hesitant on going about the fix that way. What fixes it today doesn't guarantee a fix tomorrow. Save yourself some money and find someone with a DRB or Snap On that reads live data so you can see what is happening real time.

Worth every penny of a diagnostic charge to fix it right the first time. Take a lesson from the guy you bought it from that spent big money on a pump only to find out that wasn't the issue.

 

[Joe Mc]

Road Dog mentioned above: "a loose fuel line connection at the tank let air get sucked in once in a while. Those air bubbles caused a fault as they passed through the pump".
I had a similar situation with "air in the fuel line", although mine was from the tank to the LP, which at the time was still located on the side of the engine. Noticing your truck is a 99 as is mine may I suggest the following:
Get a mirror & flashlight and situate yourself so you can visually inspect the top of the fuel tank module, check the lines at the top of the module for moisture and what might appear like a tiny speck of dirt. What I ended up finding was a "pinhole" at the bend in the suction pipe (tank to engine feed line). What would happen is air would get sucked in as the fuel was being "pulled" thru the line causing pockets of air. The fix for me was to install the Vulcan Draw Straw eliminating the original metal piping. This I did probably around 2002 or so. Just figured I'd mention something you might want to take look at before going crazy and spending $$$ for someone else to try and figure it out. At least, if you perform this "check", it'll remove the potential delivery system problem/air in fuel equation.

 

[R0b]

I talked to the mechanic that has worked on this truck from almost new he fixed this same problem before with a new map sensor so he got me a new one at no cost to me because the one he put in before has a lifetime warrantee now I will change it and see what that does. If it fixes it great if not IM out 30 min of my time either way come Monday it will be on a live scanner that logs all data for a few days to see if there are any hidden issues and the PO is paying for it. Before anyone says its to good to be true the PO is my boss at a small tree service and one great guy.