Question on rail drop

[Fitchconstruction]

Thoughts on being able to drop rail pressure from 21k to 8k at WO. Have dual feed rail without relief valve, mod cp3 pump, 90 horse injectors, and FASS 150. With smarty removed and TST on 6/6 should I be able to pull the rail that low? Once pressure comes back it jumps to 26k.



I have noticed that fuel pressure latley from Fass has been jumping all over the place. One secound it will be 15psi and then 2psi. Pump doesn't change sound. Bad FASS?

 

[rbattelle]

Sounds like a bypass problem with the FASS, if the pressure gauge is accurate.

I'd start there.

Ryan

 

[blowinsmoke]

mine's doing the same thing. updated my smarty to revolution, about 2 weeks later it started doing it ( running mild rp) i've got a dual feed line on the way. my fuel psi is all over the place but i think it is due to the commander's sensor

 

[blowinsmoke]

I called industrial on my problem. they said it was either a bad relief valve or injectors. told me to check it by taking off banjo bolt on top of valve, start and see if any fuel comes out while running. got a dual feed line on the way, also put my manual gauge on to check fuel psi. it was a constant 10, never could get it to drop

 

[JStieger]

With smarty removed and TST on 6/6 should I be able to pull the rail that low? Once pressure comes back it jumps to 26k.

You're maxed out on the CP3.



Turn down the Te setting on the TST.



With a Floor It Stage 2 pump, 100 HP injectors, no smarty - I could only run maximum TST 5x1 before I lost rail pressure. This was also verified on the dyno many times. This was about 575-596 rwHP (uncorrected) with small BD twins so power "might" have been higher with less restrictive twins that supplied more air.

 

[Fitchconstruction]

I have not had the time to look at FASS yet. With fuel pressure jumping all around at the filter (0-4-15-2-8-12) with little throttle I feel it's the FASS. I replaced the fuel filter thinking it might be a dirty filter.



I will try running the truck stock and see what rail pressure is at. I believe with a FASS150, dual feed line and IIcp3 I shouldn't be able to max the system out with just the tst. Correct me if I'm wrong though.