fuel pressure gauge reading 0psi
 

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?:argh::scare2::s:

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.

Its one of the electrical ones. It has two post on the sending unit one that goes to the gauge, and one of a ground. I ran the ground to the battery and used their wiring harness for the wire to the gauge. Then coming from the back of the gauge included in this harness is a red wire for power when you turn the key on. A yellow wire for the constant power. A orange wire for the dimmer and another ground

wrong.


there would be negative pressure in the line or vacuum in the line from the injection pump pulling the fuel rather than the lift pump...

having less than 10psi while driving and running WOT is quite literally damaging your injection pump...

sure it can run like that for a while, but not for long...


what you fail to realize is that fuel is the ONLY lubrication and coolant for your injection pump...

it is just like running an engine with no oil pressure and zero coolant. sure it'll run, but not for long...

you need 14psi minimum to keep the vp44 adequately cooled down and 10psi MINIMUM to keep the pump within bosch runnin specs. 7spi is only spec for engine cranking, not engine running conditions...


I run 20psi idle and with maximum fueling at WOT it only drops to 16psi.

jigabop....... I got thinking about the Injection pump pulling the fuel and I agree with vacuum rather than pressure. WHS7221, I would suggest making sure the gauge is wired correctly if you are sure it is you may have a lift pump on its way out. Good luck!

I have had a couple of issues with my glowshift gauges, but with my fuel pressure gauge, when it had issues, it would go all the way up, not down.

on another note that nobody touched on here, your vp44 needs more than 12 psi before you are returning any fuel to the tank. if you are not returning fuel to the tank through your ip, then your ip is not getting the cooling it needs. The vp44 relies on excess fuel to keep it cool. if it overheats, it fails...:humm:

you always need more than 12 psi for your ip to last. keep in mind though, it doesn't tolerate any more than 25 psi

FASS DDRP Dodge Direct Replacement Pump - 98.5-02 Dodge Cummins
Any thoughts on this pump?

I have seen no evidence to back this up...

max input pressure is not documented anywhere by bosch.

high input pressures can cause hard to start issues, but I have seen people running 27psi to 30psi without issues.

I would be worried that seals might leak from the high pressures though but again it's all word of mouth, I have seen no documentation to support the theory.

now for the low pressure side we do have documented evidence from bosch and cummins showing specs.

13-14psi = overflow valve opening pressure 10psi = minimum operating pressure 7psi = minimum cranking pressure. all of which can be found in the cummins service manual. nowhere does it state maximum input pressure though.

to be safe though I run at 20psi input pressure and 16psi is as low as my pressure drops with the vp44 pushing so much fuel it actually sputters and falls on its face if I push it any harder (basically I'm sucking it dry with my injectors and wiretap fueling)