Think of the vp44 like the ds4. They both use a pump mounted driver that is cooled by the fuel running through it. The primary difference is the vp44 runs at MUCH higher pressure(more than double). But both pumps can run without fuel pressure to them, but only for a short time before damage occurs. Cummins used a carter rotary van pump on the 1st 24 valves and 03 to early 04 common rail engines before they came to there senses, and Dodge yanked the engine mounted pump off and eventually installed one in the tank(for a short while they were using a frame mounted lift pump as an upgrade). I did ALOT of those carter lift pumps back in the day, and subsequently alot of vp44 pumps that got starved for fuel and died from it.
When the pump driver is going, sometimes pouring cool water on it will get it started back up so you can limp it home. I also did quite a few ecm's on the 24 valves for the 98-99 trucks with no starts, or they died during a flash. Try explaining to a customer that his truck he brought in running perfectly fine is now dead as a door nail because you were doing a flash update for a recall, and they now have to wait 4 days for a replacement because they are on star line restriction and can only come from Cummins. And to top it off, the replacements many times had to be flashed as they would come blank, and don't ask how HAPPY a customer gets when the replacement ecm dies during flashing. Oh yes, the good old days of working on the all mighty never breaks Cummins(or at least that's what so many owners of them believed).
