So I went a bought a glowshift fuel pressure gauge. I know they aren't the best I just wanted something to get me by. So I installed it on the outlet side of the fuel filter and it was reading around 12psi. But any amount of throttle it dropped to 0psi. So I moved it to the IP and its the same story. If the actual pressure was 0 how could the truck still be running?

 

Because the injection pump can still suck fuel from the tank, it just stresses the hell out of it, since its doing all the work and its creates extra heat that it cannot handle. The Vp44 Can run just as well alone, but it will eventually lead to failure of the injection pump. Check you fuel filter to see if its dirty if it is replace it and if it reads 0 psi at WOT then replace the lift pump. Should be no less the 8PSI at WOT

 

But if the lift pump was bad would I still hear it run?

 

Why did you want to check the lift pump pressure to begin with?

 

Didn't have a reason at all. The truck starts just fine and it runs fine. You give it throttle and its going. Just saw the gauge thought it looked cool so I went ahead and got it.

 

12-15 psi is where you should be at idle but sounds like the guage might be faulty when the load is increased

 

Is there any way to check this? I really dont feel like buying a injection pump

 

I'm not sure why it is going to 0 psi line pressure. If you have 0 psi how could the truck be running. Even if the injection pump was pulling the fuel there would still be pressure in the line.

 

That's my thought on it. And I can hear the pump run if I bump the starter

 

This may be a dumb question (but I'm not familiar with that pressure gauge) Is it 100% mechanical or is there any wiring involved? If it's 100% mechanical I would think something is screwy with it.