caleb c.

I have had my gauge turned off for a few weeks because it was leaking a little bit (no isolator just needle valve). Anyway, I turned it back on and it idles at about 10 psi. I had it set at about 18. And then all of the sudden it will go back up where it should be. It alternates like this every hour or so of driving. I have a holley blue feeding the stock pump. Why would it work right sometimes and not others? As far as I know it has good power and ground.It has me a little worried because it is running 5-6 psi when cruising.Thanks

STACKED

i have the same problems. how is yours wired, through the stock lift pump wires or off its own hot wire through a relay from the battery.

caleb c.

I have the hot wire coming from the stock lift pump to a relay and then to the pusher. I just changed the fuel/water seperator filter and it didn't change anything.I know the pump is running, you can hear it, so I don't know what the problem is.

eric13

Maybe the stock pump is finally crapping out.

duallydave

i wnder if your stock pump is shorting out or losing power intermitently?maybe try wiring the holley diferently,not being trigered by the stock one.also check the fuses under the hood and give them a wiggle,i had my fuse box open trying to locate the wire for the liftpump and i must have wigled the fuse to the liftpump and it had no power and the truck stalled,it sounds like the stock pump is losing power and the holley has to push thru the pump instead of it helping,i had my holley on a switch till i wired it properly and if i truned the switch off while driving my presure would drop like crazy,i guess if a pump isnt pumping its a restriction,

farmer dave

It might also be the injector pump starting to give out a create a restriction. Have you checked for codes?

caleb c.

I haven't checked codes yet...I'll do that. When I go to start it up it idles at 18psi like it should and then after 5 seconds or so it goes down to 8psi. What are the failing VP codes?

caleb c.

OK, don't need to know what the VP codes are anyway, didn't have any codes. Any other ideas? Btw, I put a new lift pump on when I put on the holley pump, think it could be dead already? that was only 10-12k ago.

farmer dave

It could be. I would still check the fuel pressure because sometimes it doesn't through any codes even though the pressure is low.