Attention: TDR Forum Junkies 
60K with stock pump ...
I have 60K miles on my 99 and the stock pump still works fine, 13psi at idle, never less than 1-2psi at WOT (totally stock fuel system with Sportbike's 75HP injectors, EZ and Hot PE). Now, before you guys start telling me that 1-2psi is too low, I don't totally agree. Per Bosch's training material for the VP44, it was designed to "SUCK" fuel from the tank by itself and through a filter. Well in our application, Cummins added the lift pump to help it out. The way that low pressure can hurt the VP44 is when the lift pump goes kapoot! Then you guys see 0psi, but it's really maybe more like -10 to -12psi (WAY under vacuum). Check out the guys' posts on the "pump, lines, and whatnot" thread on the next to last page that have SPA gauges to measure fuel pressure. Two guys both said they saw -11psi when their pumps took a dump - that's because once the pump quits, if it locks-up it's like closing a valve in the fuel line. Then the VP is pulling against a wall basically acting like a vacuum pump. When diesel is put under enough vacuum (I'll have to do some work next week to determine the vapor pressure of diesel at ambient temps) it will vaporize. Now you start getting vapor into the VP and the truck starts bucking, no lube or cooling for the VP, and enough of this and the VP is history! But some guys say their truck ran fine and checked the pressure and it was zero - my theory is these pumps weren't locked-up, and therefore allowed fuel to flow through them - and the VP was doing just that or the truck wouldn't run fine.
Those are my theories, anyway FWIW. So, I'm of the opinion (and I think Bill K. agrees with me on this) that if you have positive pressure at the suction of the VP44 (>0psi), you're VP should be fine.
Having said that, Tom I would like to know how you re-plumbed your fuel system with SS tubing. I am currently looking at this myself because I would like to move my lift pump back and add an in-line fuel filter - then hopefully I won't have any future problems with my lift pump.
I have 60K miles on my 99 and the stock pump still works fine, 13psi at idle, never less than 1-2psi at WOT (totally stock fuel system with Sportbike's 75HP injectors, EZ and Hot PE). Now, before you guys start telling me that 1-2psi is too low, I don't totally agree. Per Bosch's training material for the VP44, it was designed to "SUCK" fuel from the tank by itself and through a filter. Well in our application, Cummins added the lift pump to help it out. The way that low pressure can hurt the VP44 is when the lift pump goes kapoot! Then you guys see 0psi, but it's really maybe more like -10 to -12psi (WAY under vacuum). Check out the guys' posts on the "pump, lines, and whatnot" thread on the next to last page that have SPA gauges to measure fuel pressure. Two guys both said they saw -11psi when their pumps took a dump - that's because once the pump quits, if it locks-up it's like closing a valve in the fuel line. Then the VP is pulling against a wall basically acting like a vacuum pump. When diesel is put under enough vacuum (I'll have to do some work next week to determine the vapor pressure of diesel at ambient temps) it will vaporize. Now you start getting vapor into the VP and the truck starts bucking, no lube or cooling for the VP, and enough of this and the VP is history! But some guys say their truck ran fine and checked the pressure and it was zero - my theory is these pumps weren't locked-up, and therefore allowed fuel to flow through them - and the VP was doing just that or the truck wouldn't run fine.
Those are my theories, anyway FWIW. So, I'm of the opinion (and I think Bill K. agrees with me on this) that if you have positive pressure at the suction of the VP44 (>0psi), you're VP should be fine.
Having said that, Tom I would like to know how you re-plumbed your fuel system with SS tubing. I am currently looking at this myself because I would like to move my lift pump back and add an in-line fuel filter - then hopefully I won't have any future problems with my lift pump.
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