2001 GMC duramax losing prime

[KB9UDE]

I have a 2001 DMAX with 145k miles. Every now and then if the truck sits for a week it will start, run for 45 sec and then die. I have to open hood and prime then truck starts and runs fine. I never have this problem if I drive the truck daily... Any thoughts??

 

[flatlander 2500hd]

There have been known problems with the nylon bleeder screw cracking or the o-ring no longer sealing properly. When I had my Duramax, a mechanic friend suggested that I keep another bleeder screw in the truck at all times.

 

[DaveOmak]

Seen this before.
There is probably a filter or fitting that is "loose" between the fuel tank pump and injector pump.
The fuel will drain back to the tank while it is sitting idle. The fuel pump in the tank doesn't fill the filters before the injector pump runs out of fuel.

Have the filters been changed or something been done recently to initiate this situation? Would give you somewhere to start. Dave

 

[Diamondpilot]

I agree with the others. I think its in your under hood fuel filter or filter housing itself/plastic bleeder screw.

I maintain a 07 Dmax for a customer and I had a 05. We have never had any issues but I have hear of those who have. I change the fuel filter every other oil change. Its about $40 but money well spent. I also carry a extra filter in all diesel trucks. Just one bad tank of fuel and you will wish for it.

Chris

 

[WH401]

The fuel pump in the tank doesn't fill the filters before the injector pump runs out of fuel.

The Duramax doesn't have a lift pump, the CP3 sucks all the fuel from the tank and through the filters by itself. This tends to be one of the flaws of not having a lift pump, i.e. there's no method for the lines to be pre-primed before the CP3 runs out of fuel.

 

[Ford tractor]

The Duramax doesn't have a lift pump, the CP3 sucks all the fuel from the tank and through the filters by itself. This tends to be one of the flaws of not having a lift pump, i.e. there's no method for the lines to be pre-primed before the CP3 runs out of fuel.

Exactly. Add in that the new ULSD fuel seems to be "dry" and leads to hose cracks and you will have foamy fuel. That will erode the injectors ($4000 to change) and the pump. It's why I ordered a lift pump after replacing cracked hoses.