need help "low fuel pressure"

[ls1_rulz]

HI

just installed trilogy supercharger kit on Marauder 2003

Mods : Stock Engine heads + Cams only the supercharge kit 9.5 PSI + Mafia set to 2
fuel : 1 single GT super pump + BAP KB should handling 400 RWHP easily

the problem (Fuel pressure) :
@ Idle the fuel pressure 55~60 PSI
@ WOT 3000~ 4000 RPM the pressure 50 PSI
@ WOT 4000 ~ 5000 RPM the pressure 35 ~ 40 PSI

the A/F
3000 ~ 4000 11.8
4000 ~ 5000 12.5


note : I check the voltage for the fuel pump it's around 13.8 driving normal and @ WOT 17 so the BAP working perfect


any suggestion about this problem ?

[SC Cheesehead]

Did you upgrade to 39 lb fuel injectors?

[ls1_rulz]

Did you upgrade to 39 lb fuel injectors?

yes i forget to mention that i already upgrade the injector to 60 LB

[DOOM]

Who tuned the car?

[mcgyver59]

Fuel pressure is fine AF is not. Go to a dyno. Mail order tunes are so.you.can.drive and see your tuner without problem.

[ls1_rulz]

the car tuned already and the drivability is fine and A/F @ normal drive 14.5 ~ 14.3
and also the Fuel pressure is ok but the problem only after 3500 RPM @ WOT the fuel pressure drop less than 40 PSI

i tuned the car with Sniper deltaforce and innovate WB

[mcgyver59]

Did you log fuel pump.duty.cycle? Did you replace the.corrugated line in the tank with good.submersible fuel hose?

[ls1_rulz]

Fuel Pump DC% 80 ~ 85 %
and also yes i replace the hose and the submersible with good one and also i upgrade the the fuel pump wire

[mcgyver59]

If the duty cycle is where you say it is, sounds like you just need to further tune the car.

[mcgyver59]

Also...under returnless.fuel pump there is a pressure vs. Ambient temp section. Set everything to 40 and FP will be at 39-40 at all times.

[ls1_rulz]

do you mean this table ?

pic @ attachment

[FordNut]

Just wondering... Did the FRPS get connected to the vacuum source that sees both boost and vacuum? Some of the Trilogy installations connected it pre-blower so it only sees vacuum.

[sailsmen]

What is the FI Duty Cycle?

[ls1_rulz]

Just wondering... Did the FRPS get connected to the vacuum source that sees both boost and vacuum? Some of the Trilogy installations connected it pre-blower so it only sees vacuum.

thanks for your replay but can i get more info also if you have pic it's better



thanks again

[FordNut]

Don't have a pic, but it's pretty simple. The FRPS should be connected with a T to the fitting where the boost gauge is connected in order for the fuel pressure to be boost-referenced.

[RacerX]

Just wondering... Did the FRPS get connected to the vacuum source that sees both boost and vacuum? Some of the Trilogy installations connected it pre-blower so it only sees vacuum.
As soon as I saw the thread title, this is what I thought!

Pics and thread courtesy of Dennis:

Look at the last couple of pics in post #7. You need to make sure your FRPS (Fuel Rail Pressure Sender) is seeing boost as well as vacuum.
http://www.mercurymarauder.net/forums/showthread.php?t=71238

[ls1_rulz]

As soon as I saw the thread title, this is what I thought!

Pics and thread courtesy of Dennis:

Look at the last couple of pics in post #7. You need to make sure your FRPS (Fuel Rail Pressure Sender) is seeing boost as well as vacuum.
http://www.mercurymarauder.net/forums/showthread.php?t=71238

thanks alot I'll try to make this and i'll feed you back

[Vortech347]

Change your fuel filter lately? Alot of times the filter people are running flows enough gunked up for N/A they throw a blower on and its no longer sufficient.

[Taemian]

Any resolution to this problem??