Engine/Transmission (1994 - 1998) Loosing Prime

[EWalshak]

My 98' 12v has progressively been getting worse. It is loosing its prime and unless I bleed fuel up to the injector it wont start. The lift pump is new with only a few hundred miles on it. I have not checked to see if it is "making oil". Im not sure if this can be an issue with the CTD. Does anyone have a good place to start? Tonight I was able to get by with pumping the manual primer on the lift pump and she fired right up but I hadnt tried that other than tonight. Thanks in advance for any help.

 

[fest3er]

Losing prime? Alas, that happens to all of us as we age. Oh, wait. You're talking about your truck.

If your fuel system is draining itself, then you have a leak in the lines between the tank and the p-pump. Check the return hose behind the fuel filter assembly. Check the hard supply line between the filter and the lift pump. Check the hard return line.

If you haven't opened up fuel lines in a while (enough time for all the fuel to evaporate) and you smell any fuel under the hood, you have a leak. It may only be small enough to let a little fuel out and let air in, but it's a leak nonetheless.

There have been plenty of threads about this in the past few years; 'search' is your friend. Actually, these threads have been going on for at least ten years.

 

[GAmes]

Joe G will send it to you direct, but here is the good info. Joe G's fuel system writeup - Dodge Cummins Diesel Forum



In addition, there is this thread. https://www.turbodieselregister.com...ion-1994-1998/204958-lift-pump-failure-2.html The picture in post #19 is an item that is easily overlooked.

 

[JKosten]

Exactly what GAmes said.

My truck was leaking air into the pre-heater. I also changed the overflow valve.