Hi all, I posted this question last night but the post is now MIA.

I installed ISSPRO Pyro, boost and fuel pressure guages yesterday, pyro and boost guages work fine. The Fuel Pressure guage reads zero.

I have tapped into the top of the filter housing and there is no diesel fuel making it to the issolator. I then tried a tapped banjo bolt at the outlet of the filter that feeds the vp44, still no fuel into the braided hose and into the issolator. Is the Lift pump totally dead? When I cycle the key and bump the started I can hear the lift pump run.

Here are the specs:
1999 4x4 quad cab long bed
54,000 miles, (owned since 29000 miles)
same lift pump since I have bought it
no noticable loss in mileage running empty and loaded.

 

Dead lift pump? maybe but I would bet on a bad isolator. Hook the gauge direct and see what it reads

 

no fuel had made it into the issolator, hooked up gauge directly to steel braided line that connects to the test ports or the banjo fitting, still no diesel fuel.

 

Have you tried loosening the banjo that goes into the filter housing to see if any diesel leaks out when the lift pump should be running? Or can you even hear the lift pump trying to run?

I'd open that banjo a little bit and have someone bump the starter to put the lift pump into it's long priming cycle. If you don't hear the pump or if you don't get any fuel at that connection it's RIP lift pump.

JM

 

I can hear the lift pump run when the starter is bumped, no fuel comes from the cracked open banjo bolt.

 

Looks like a dead lift pump, good thing you caught it. I wouldn't move the truck until you replace the lift pump.

 

How much fuel is in the tank right now?

You might want to take the supply line of the back of the LP and see if anything will even drain out of there. It might be that the LP lost prime and isn't picking it back up. I've had trouble with that once before, but all my lines were dry from changing out banjos and I didn't have much fuel in my tank so there was no gravity feed.

But if the truck will start and run, then we can rule that out since the VP44 is pulling fuel through the LP.

 

installed new carter lift pump and that seems to have fixed the problem, 16 psi at idle, 14 psi at cruising speed, 11 at WOT.

Only problem I had was the high flow tapped banjo that I snapped in half at the drilled holes with little force

hopefully I didn't damage the vp44 with the dead lift pump

 

Did the broke off end of the banjo bolt come out easily?

 

I spun the broken shaft out with my finger, there was no resistance.