mstep3

I've been running a FASS DDRP for about 4 years now. When I first installed the pump I would always run about 19-20 psi at idle. The past year it has been steadily getting higher. Now I'm running at 23-24psi at idle. Why is my fuel pressure slowly getting higher? I thought these pumps were supposed to lose pressure over time. Anybody else had their fuel pressure get higher over time running FASS fuel pumps. I know it doesn't have anything to do with my fuel filter because I haven't changed mine in about a year.

KATOOM

I'd confirm your gauges accuracy will another gauge or a tester. If you have the DDRP then you probably still have the banjos with the shrader valves which will hook up to a test gauge.

nickg

fuel pressure could rise if you have your sender before the fuel filter, or maybe some thing is jammed in the pressure requlator

KATOOM

Fuel pressure shouldn't rise ever, even if the sender is pre-filter because pressure is regulated by the fuel pump. But if the regulator is dirty is fouled up then, yes, it could affect pressure.

mstep3

looks like i must have a problem with the sender....i've noticed that the fuel pressure gauge doesn't set back to 0 after the engine is shut down & then turning ignition on....still shows 2-3 psi on gauge......the sender for fuel pressure gauge is probably 3 years old or so.....is that about how long they last before they are shot....

KATOOM

They can last forever but thats not to say that they're impervious to failure either. How far from the VP is the sender and where did you tap into the fuel system to take the fuel pressure readings from?

mstep3

i'm using one of those vulcan universal fuel lines from geno's and i have it attached to the fuel pressure port on the vp-44....i'm also using a needle valve on the line before the sender....it has worked great for about 3 years but just lately that it is giving bad readings.....seems like the sender may be giving false readings.......

KATOOM

People will try to claim that reading directly from the VP is OK but its not. Yes, a sender may last for however long they do reading from the VP inlet but the VP fuel pulses are just to violent. The best place to pull fuel pressures from is as far from the VP as you can get and if you're still using the OEM fuel filter housing then reading from the housing outlet line is the best place since you're still post fuel filter but as far from the VP as you can get. Then running fuel line from there up to the sender should help reduce the VP's fuel pulses as much as you can.

mstep3

thanks for the input. i know having mine hooked up to the pressure test port on the vp-44 has probably worn out the sender prematurely. I am using a needle valve that is barely cracked open to get a good pressure reading though so i thought it would protect it fairly well. i definitely think the sender has issues though because i get some crazy readings when the needle valve is completly closed off & the gauge is usually showing pressure even when the truck is shut down and the ignition is on. looks like i'll just need to get a replacement for the sending unit....could be some junk stuck in it but i kind of doubt it seeing as how i've got it hooked in after the fuel filter.....

hawaiianbro

i had the exact same problem. our trucks have pressure spikes on startup which will kill your sender fairly quickly if you don't have a pressure snubber. i have an electric isspro gauge and when the sender died i sent an e-mail to their customer support and he sent me a replacement sender free of charge. i ordered my snubber from genosgarage for a few bucks. hope you get it fixed!