Curiosity's got the better of me on VP44's?
 

Due to my lack of knowledge on diesels and I've been through the ringers with having to replace a VP44, I was wondering......this gets me into trouble! Most often people refer to these injector pumps as fragile, tempermental, etc. Seems to me as if the problem was in the old Carter lift pumps? Would I be wrong? I know "LSD" fuel did'nt help, but it keeps coming up that heat dissipation, vibration, and the fact that it's a vane pump, makes me question if it was the right lift pump for the application. Guess that's why most seem to go with a FASS or AirDog system? I'm sure, being mechanical it's bound to go out again..... eventually, but for those who have upgraded lift pumps what's the longivity of service as opposed to stock? Just curious:humm:?

Low pressure stock pumps
 

The stock pump only supplies 5psi and since the diesel fuel also acts as a lubricant when the lift pump begins to fail it starves the VP44 for fuel and kills it. A FASS or Raptor normally runs around 15-17psi and provided better cooling and lubrication.

You both are correct. :tu:

Also, the VP44 uses fuel for lubrication and cooling. Without the proper flow, there isn't enough cooling or lubrication.

I can tell you this that over stock LP, and a aftermarket LP. I personally have an airdog. The aftermarket pump makes the motor run A LOT smoother and quieter. So not only only is it helping keep the VP cooled and lubed better, its also saving on other components because its not having to thirst for fuel.

Good point Barry. The FASS/AirDogs also remove air from the system which can cause damage to the components.