My truck died and won't start. I bought a new PMD from Heath and installed it and same problem. Anyway, I thought I had air because the thing just cranks and cranks. I noticed that the fuel shutoff valve is opening but not all the time. When it does open it seems to pull fuel down into the IP but it never gets to the injection lines. When the injection lines are wide open they are not even dropping an ounce. There is simply no fuel to the injectors. My lift pump is functioning fine. Is there something holding the fuel up that is electronic that needs replaced? Is my IP toast? Thanks in advance I am very frustrated. BTW the fuel is returning out of the fuel line out of the pump, it is just not entering the injection lines.