03 Ram doesn't want to start
 

My 03 Ram Cummins Diesel doesn't want to start. One mechanic charged out the in tank lift pump and then installed bypass hardware at the fuel filter. That didn't fix it. The next mechanic said that the injection pump was only operating at about 50% . Put in a new injection pump. It still doesn't want to start. The batteries are fresh. The terminals are clean. I have two choices for getting it to start. Park on a downgrade, let it roll and dump the clutch in 2nd or 3rd. It will start. The other way is to plug in the hot start about 4:30 am and it usually starts. I can't be getting stranded. I need the right information about what needs fixing. Guessing just costs money and doesn't solve the problem. gus