Pretty new to the diesel world so I am pretty unfamiliar with these types of engines. I hear mostly nothing but bad things about the 6.5, but a family member recently purchased one that was running fine and suddenly died. We have not been able to get it to start since. Engine cranks and cranks but wont turn over. I diagnosed the issue that it was probably not getting any fuel to the injectors and I was correct. I decided to check and see if fuel was being pumped out of the lift pump, and it appears fuel is not reaching that point either. We have almost completely filled the tank, so that it probably not an issue. I have replaced the lift pump and that did not resolve the issue. I am having a hard time figuring out why no fuel is reaching the lift pump. When the pump is running, the fuel line going to it vibrates as well as the lift pump. I figured this might be normal, but I wasnt sure if it was supposed to vibrate this much. The only thing that i can figure is that there is something wrong with the sending unit? Any help would be greatly appreciated.