got a 03 f250 6.0, installed arp studs,egr delete,sct livewire ts, new oem headgaskets,injector o rings-whole top end gasket set new,cleaned veins and turbo,blue spring mod,just put in new motorcraft filters. its got the stock pump still and runs like crap when punchin it at high hp tune. fuel is 55-60psi tho at test port. injectors are all good,hooked up to scanner and everything looks peachy. anybody have this same issue with good pressures but not enough volume on stock pump with high hp tune? and ive herd bad things about the FASS pumps, they get any better? dont really wanna guess but pretty sure its the pump not holding up to the 120 hp sct tune, runs fine with lower hp tunes. any suggestions would be great,thanks!!

 

Interesting....I cant see the fuel pump causing the issue just cause you switch tunes. The OEM pump is always pumping the same rate regardless of the tuning.

 

Higher hp tunes=more fuel... Stock pump can only push so much.

 

Yet you quote 55-60 PSI which shows a healthy fuel pump...

 

psi and volume are totally different. Thats why im.asking in my first question if anybody has had the same problem and fixed it with larger pump with more flow..gpm...

 

If the psi is at 55-60, the flow is there also. If not the psi would drop.

Where are you measuring the psi...at the output of the fuel pump (input to the secondary fuel pressure regulator)...or the output of the secondary fuel pressure regulator (input to the heads)?
If the pressure on the input to the secondary fuel pressure regulator is staying at 55-60 and your having flow problems, this either means you are not getting enough flow out of the secondary pressure regulator or you have a restriction in the banjo bolts at the head. The way to prove to yourself which is your problem is to test the pressure on the lines leading to the head. If this pressure is 55-60, then fuel is not able to flow through the banjo bolts. You can then drill out your banjo bolts or get rid of them entirely by installing larger fuel supply lines from the secondary fuel pressure regulator to the heads.
Once you have done this, if you notice the pressure out of the secondary pressure regulator is dropping when you run the hot tune, you have now identified the next flow issue to solve....getting the volume you need from the primary fuel regulator to the secondary fuel pressure regulator.

 

You can get 6.4 banjos from ford that flow better, have 4 holes instead of two and no restrictive screen. . I like my adII but I didn't do programmer yet.

 

I had same problems but my fuel press would drop right out to 20 psi
with 160-180 hp tunes,
My fix was
Blue return spring upgrade
6.4 Banjo bolts into heads
Only ford filters
Stock fuel pump
Fuel pressure gauge
Fuel tank sump kit
5/8 fuel line to
Simple lift pump ( I put in a Ppe set at 12 psi)
3/8 steel line from lift pump beside fuel tank
to stock fuel pump

I run mainly around 70 psi and maybe down to 60 on a hard long
demand pull