Been trying to bleed the system but motor will not start. I pulled the injectors to clean them and engine started right back. Checked the lift pump (diaphram pump) engine started right back. Pulled injector pump and had a seal installed (getting diesel in motor oil) and when I reinstalled it, cannot get the engine to run. I have been bleeding this system for 4 days and still will not fire. It has tried to run a little but shuts down while it is still turning over. I'm beginning to wonder if the pump was not damaged when they installed the seal in it. I have bleed these injectors before and I know it takes a while but they have never been like this. THere seems to be plenty of fuel going to the injectors, as before. i can tell that no fuel is making it through the injectors because the truck does not smoke at all when trying to start. Has anyone got any suggestions as to what is wrong?