Converting to static fuel pressure, 2012 F150 Coyote 5.0L

[96gt4.6]

I'm currently using a stock F150 Coyote/ECU, and want to convert to running a static fuel pressure like the FRPP Coyote Power Pack does. The instructions in the power pack, say to supply 55 psi constant to the fuel rail and use a vacuum referenced regulator.

I plan on using a Corvette fuel filter/regular assembly which produces 55-58 psi regulated, however no vacuum reference. My question, is in the tune, as you can see on the Ford Racing computer, the values are set to 55 psi:



And here is my stock tune, which appears to have a slight variance in pressure:



I'm assuming this is the proper area to be changing to run a static pressure? I'm using the stock injectors, and the motor is entirely stock.

[96gt4.6]

Bump.

Any help appreciated

[AKDMB]

Also curious about this, using an AEM regulator with my build, going to set to 55psi as well. What's the purpose of the vacuum reference in a supposedly static system? Does the fuel pressure deviate from 55psi with the vacuum reference? I know very little on fuel system's.

[96gt4.6]

I can help answer part of that AKDMB. The vacuum line on a regulator that has one produces a pressure drop when there is manifold vacuum present. The purpose of this is to offset the effective increase in injector size (due to manifold vacuum pulling fuel from the injector vs. WOT where there is no vacuum present) at idle.

[96gt4.6]

Bump for any help.....

[Nader]

Yes you would set it to the same value matching your base fuel pressure with no vacuum. 55's for example. I would recommend running vacuum referenced though.

[96gt4.6]

Thank you sir!

[AKDMB]

So basically this tells the PCM, don't mess with the fuel pressure, because the vacuum referenced regulator handles it on its own, correct? In a normal Mustang the motor electronically handles the pressure, but here the regulator handles it.

[96gt4.6]

Correct, for the most part. The 2011-14 Mustang and F150 use an MRFS (Mechanical Returnless Fuel System). Although they have a fuel pump driver module, they do not operate like the traditional ERFS (Electronic Returnelss Fuel System) of years prior. From my understanding, they have only a low/high speed for the in tank pump, which has a built in regulator set at 55 psi on both the F150 and Mustang 5.0L. The low/high speed setting does not affect pressure, just flow, from my understanding. The only reason they have a fuel pump driver module is for this low/high switch, and as a shutdown system (there is no inertia switch on them). The FPDM (Fuel Pump Driver Module) receives a signal from the Restraints Control (airbag) module if there is a crash event, and kills the power to the pump.

Someone, please correct me if I'm wrong.

Knowing this, even the factory doesn't have a vacuum referenced regulator. My guess, as you can see in my original screen shot with the varying pressures, they have accounted for the vacuum offset in the tuning and use a fixed pressure, with agrees with the factory service manuals description of the system operation (where I read the above information).

I'm going to leave my values stock and see how my trims look at this point.