Im running without using a needle valve 25ish psi I put a needle valve on due to the pressure killing my isolator. I needle it down on the gauge to show 21psi with TST on 7 and smarty on I never see below 15psi and that is just a spike reading than goes to 17 and back to 21psi on cruise. to me the big concerns are and were was increasing my complete fuel line size did to 3/8 ID put in 1/2 in draw straw and have never had a problem with my fass 150. besides its always been noisy. no problems with this set up for 2 years. I do changed my stock fuel filter every 5k miles no matter what.

 

Which elements (micron ratings) are you running in the FASS and stock locations? Why did you decide to keep both filters? I have been running the stock LP and a pusher LP for ~7 years with fuel pressure around 10 idle and 5-6 WOT (seldom run WOT except on the dyno and for the occasional ricer). Original VP, original LP and stock replacement LP on the frame. I am just getting nervous on the lifespan of the pumps, so I'm planning a FASS or AirDog soon!

 

I have the same set up on one of the shop trucks, and the pressure is 28psi @idle, and 22psi @ WFO.
I think both of your pumps are weak or the screen in your tank is clogged.
Something isn't right as just one good, stock lift pump should be @15psi.

 

thanks, i assume the same: weak, plugged or one dead, but i get good (enough) positive pressure that i haven't worried about it much. i didn't monitor the pressure for a few years as i'd pull a reading from the test port occasionally and the fuel filter always filled after a filter change... if it killed my IP I could justify an upgrade!

 

not to rain on anyones parade but Holly blue pumps and diesel fuel don't get along too well and will fail before very long. Some people get lucky and have them last along time but most of the ones i have seen only lasted a month or 2. The fass pumps now come with a lifetime warranty and are very quiet. The 200 gph pumps still make some noise though

 

Uh, OK there Fass Salesman, LOL
Even if that were true, they are re-buildable at a wopping $20.00.
You get a new rotor and new vanes in a cute little package. We run alchohol through them and they last a couple seasons, so a little diesel is a LOT less destructive.

 

I have just the 150fass pump not the complete filter. I have 10 micron fleetguard filter and prestrainer prior to the FASS.