hey everyone, i have mentioned i few times about my truck, it dies sometimes when i fire it up and soemtimes feels like it starves for fuel and bogs down. i pulled it into the shop, diesel shop here in town where i work and some of the mechanics told me after i explained what happens that there is a check valve between lift pump and injection pump that could be stuck open and could cause fuel to drain back into fuel tank, and for that reason loose fuel pressure and make it bog down and starve the injector pump of fuel...
is this a typical thing?? could that check valve cause this issue?? please i need some input cuz dealer hasnt been able to help me with the issue...

 

I am assuming you have an 05 cummins. This fuel system does not have any valve between the lift pump and the injection pump. The fuel flows from the lift pump through the filter to the injection pump, which pressurises the fuel to the rail. Most of the fuel supplied to the injection pump will be used for lubrication and cooling and be returned to the tank by a direct line. The injectors will also bypass a little fuel and will be returned to the tank through a machined passage in the cylinder head that tees into the injection pump return. A pressure relief valve is also teed into this line and should only return fuel if the pressure is high enough or it is faulty. I would have a shop that is very familiar with cummins hpcr fuel systems perform a full fuel system test including the injector return volume test. Pinpointing a fuel leakage issue is not easy or cheap without the special tools needed. Even with the tools it is not usually cheap.