Runs for awhile then shuts off

CHAD ADAMS

MEMBER
1998 DODGE TRUCK
5.9L
6 CYL
TURBO
2WD
AUTOMATIC
300,000 MILES

12 valve diesel.
Truck shuts off from lack of fuel to injection pump/injectors. Replaced the block mounted lift pump and fuel filter. The preheater assembly was permanently removed as it is a known source of air leaks into the fuel system. Fuel lines were removed and cleaned then put back on with new clamps. Truck started and ran great for 2 days. On the 3rd day it ran for about a mile and then died and would only start by priming the lift pump. Engine will run for about 5 minutes but then runs out of fuel and shuts off. The fuel filter was removed and checked again and appears clean. While the filter was off the key was turned on and fuel came pouring out of the fuel filter housing. I was not aware that these trucks had an in tank pump as well as a block mounted lift pump and injection pump. With 3 pumps and no fuel leaks this engine should have no reason not to run.
The fuel shut off solenoid also appears to be working as intended.

5 Replies

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

Hi,

There is a check valve within the overflow valve that could be sticking causing low pressure. Take a look through this and let me know if it helps in any way.

______________________

1998 Dodge or Ram Truck RAM 2500 Truck 2WD L6-359 5.9L DSL Turbo VIN D FI
Component Tests and General Diagnostics
Vehicle Power-train Management Fuel Delivery and Air Induction Fuel Pressure Regulator Testing and Inspection Component Tests and General Diagnostics
COMPONENT TESTS AND GENERAL DIAGNOSTICS
Injection Pump Overflow Valve

pic 1

A sticking check valve within the overflow valve may cause low power. Refer to the Fuel Transfer Pump Pressure/Capacity Test. Overflow valve testing is covered in this test.

Whenever the fuel injection pump is being replaced or removed for calibration, the overflow valve must stay with the pump. Make sure a new overflow valve is used with a new or rebuilt injection pump and the old (original) overflow valve is returned to authorized repair facility with the old injection pump.

Fig. 18 Installing Special Tools

pic 2

Make sure the overflow valve is correctly installed at the fuel return line (pump outlet) (Fig. 18) and not incorrectly installed at the fuel supply line (pump inlet).

+++++++++++++++++++++++++++++++++++++

Joe

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Wednesday, May 6th, 2020 AT 8:26 PM

CHAD ADAMS

MEMBER
3 POSTS

The overflow valve or OFV was checked and appears to be functioning as intended. Are these trucks suppose to have 2 lift pumps? I was only aware of the block mounted mechanical lift pump that works off of the cam. This truck also evidently has a electric pump in the fuel tank (discovered this by accident when I turned the key on while the fuel filter housing was off for inspection). I can't find anywhere that the diesel trucks had an in tank pump this early. I know later models starting in late 2001 had in tank pumps and there were also some retrofits done to replace the block mounted electric pumps with in tank electric pumps (pushing rather than sucking). To my knowledge those were all on the later 24 valves with the VP44 injection pump and in all of those cases the block mounted pump was bypassed or removed because it would create a restriction in the system. The redundancy of 2 lift pumps doesn't make since to me on these trucks and I almost wonder if one of them could be creating a restriction on the other. I.E. The in tank electric pump is not allowing enough fuel for the suction of the mechanical pump or the mechanical pump is restricting the flow from the in tank electric pump. What are you thoughts?

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Thursday, May 7th, 2020 AT 9:21 AM

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

Hi,

Can you do me a favor? Can you check the engine code in the VIN? I want to make sure I have the exact one. I need to know if it is VIN D or something different. See the attached picture.

I'm asking because when I look through the manual, it's showing a lift pump and injector pump. I can't find reference to one in the tank.

Let me know.
Joe

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Thursday, May 7th, 2020 AT 9:00 PM

CHAD ADAMS

MEMBER
3 POSTS

There is a D in the eighth position of the VIN. Is this the position that you were referring to? Engine code D, It is a 5.9 Cummins Diesel engine. The truck was built in August of 1997 and sold as 1998 year model.

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Friday, May 8th, 2020 AT 8:33 AM

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

Hi,

That's it.

The purpose of the fuel transfer pump is to supply fuel to the injection pump. The transfer pump produces about 25 psi. Then, the low-pressure is raised by the fuel injection pump for operation of the high-pressure fuel injectors. The transfer pump is actuated by the cam.

Okay, I was reading and reading and reading, and then I saw this.

All aftermarket devices used to identify low fuel pressure are incompatible with the retrofit Electric In-Tank Transfer Pump and should be disregarded.

So, the idea that you feel there is a fuel pump in the tank makes sense if the transfer pump isn't working. Do me a favor, check pressure from the supply (transfer pump). It should be approximately 25 - 30 psi. I have a feeling someone has retrofitted it with an electric pump and the lift pump doesn't work. Ugh! This is only a theory at this point.

Let me know.
Joe