Low Fuel Pressure.

[anschutz1913]

OK so have all the mods in my sig. I have been watching my fuel pressure gauge and noticed I'm losing fuel pressure when i get on the truck half pedal or more on acceleration. Its going down to 35 lbs, and REAL QUICK. I added a fpr shim and it keeps my idle and low speed pressure much better... around 60-70 lbs. Initially I was thinking that the mech fuel pump just couldn't keep up, but Cody at PHP said that the stocker will keep up with the stage 1's... And I know its not weak because the one that is in it now is brand new from Ford... Only about 3 weeks old.

Any ideas where I might be getting restrictions?


Cody told me to switch tanks and see if the sending unit screen is plugged up... But it does it on both tanks.... maybe both screens are plugged? I change my fuel filter religously, about every other oil change, so around 8K or so. This fuel filter is about 2 weeks old.

[Patrick Feeley]

Check the FPR screen for crud. Does your 96 have the Fuel restriction Sensor on the FPR block? If so, I think there is another steel wool-type screen in the line that comes up into the bottom of the FPR. Check that too if you have it. Cheers!

[anschutz1913]

Originally Posted by Patrick Feeley

Check the FPR screen for crud. Does your 96 have the Fuel restriction Sensor on the FPR block? If so, I think there is another steel wool-type screen in the line that comes up into the bottom of the FPR. Check that too if you have it. Cheers!

I put in another screen from a spare motor I have about month and half ago or so... However I was unaware of the fuel restriction sensor... What exactly is the function of the FRS? I will check that tonight.

Thanks!

[anschutz1913]

I do have another line running into the bottom of the FPR. Is the screen right in the line or up underneath the FPR? I have a spare motor with another FPR on it and I'm contemplating just swaping the whole thing out.

[mjonesjr]

Check for leaks.

[Patrick Feeley]

For pictures of the strainer (that's what its called I guess), see post #18 of this thread: 1st gen PSD + VO + stock FPR = $h*t
Cheers!

[anschutz1913]

Update...

I found that the FPR spring was bent... Ordered a new one from Ford and put it in. Now my idle pressure is ~77 psi, my driving pressure is anywhere from 70-80 psi. and When I get on it hard it drops to around 50... Numbers more normal? I'm not sure what the full load psi is supposed to be... I just know its not suppsed to be 35 psi like it was before.

However if I'm doing 70 mph and just let off the throttle it will go up 90 psi. No shim anymore... just the spring.