Just completed engine swap for the boss. Never would have believed there were so many differences between van and truck 7.3 engines. I added and electric fuel pump to eliminate most fuel supply problems. Used the pump from the blown engine. But never seen proper fuel pulse while bleeding injectors, and with all the cranking never notice any smoke out the exhaust.
After loosing patients I gave a whiff of either and it took off instantly. Engines has plenty of diesel knock which I normally take as good compression. and has plenty of power and runs fine. (other than I'm guessing engine had rust in one cylinder as it would not turn freely over untill I spray thrust in the glow plugs holes and rocked it back and forth, not shure of the condition of that cylinder but thats another post)
Engine will start when hot but when cools slightly will not fire. Engine has about an hour of run time now and still no smoke while cranking cold. I have had tired engines, in the past, that start hard, had very little diesel knock but always had smoke while cranking. I don't know the condition of the injectors, other than it idles with no smoke. I'm guessing injection pump, but I cant think of what would be bad inside other than worn plungers? As always thanks

 

Not starting cold, then starting hot, then not starting when cools down points to glow plugs to me. Did you check them to see if good? The no smoke is a puzzle tho, if it will start on either. Is it spinning over fast when cranking on it? The starter might be getting weak, or the connections, or cables not good. Just some places to check.

 

Finally figured it out! I dimissed the glow plugs too soon. The light would stay on for 8-10 seconds and the amp showed currect draw and the usual clicking after 10 seconds. All this with 8 burned out glow plugs! New controller and 8 GPs and it starts fine!