VERY high pressure to VP44.
 

2000 Ram 3500. 5.9L turbo diesel. 6sp manual. 100% stock. No mods. 425k on odometer.
Owner lost lift pump. Rotor seized as usual.
Replaced VP44 with known good working unit.
Couldn't afford a new lift pump so he bought a cheap rotary style fuel pump. The pump was rated 10 to 100 psi.
His thinking was that the VP44 failed because of low fuel pressure and the higher pressure would solve that issue.
Ignition on, new pump on manual switch wired direct to batterys, flipped the switch, and watched the brand new fuel pressure gauge (0 to 30 psi) wrap around all the way and stopped about 15 psi other side of peg.
At this point he did something smart and turned everything off and called me.
I put on a new stock lift pump and attempted to bleed the system. At first I had some fuel coming out of cylinders 4, 5, and 6. lift pump is working as it should, but I am not getting any more fuel to come out of any of the injector connections.
I'm thinking it blew the overflow regulator and it isn't pressurizing the vp44 enough to send fuel to the injectors.
Any thoughts would be appreciated.
Thank you. Smitty

New lift pump defective. I'll post more when new one gets here.