3.8 fuel pressure

[HennessyDC]

1998 3.8 v6
KOEO: 28 psi
Engine running: 28 psi
vacuum off: rises to 38 psi
misfire/lean run issue. checked wires and coil (need to pull/check plugs) injectors firing (may be clogged/dirty, will clean/service injectors) fixed multiple vacuum issues. have and will replace up and down stream O2s. replaced fuel filter.
No codes present. had some vacuum codes, replaced purge valve.
starts without issue. pump primes, engine starts.
question is, is 28 psi too low? do i need a fuel pump? could fuel pressure be raised into 30-45 psi range using adjustable fuel pressure regulator?

 

[HennessyDC]

1998 3.8 v6 165k miles

 

[96blak54]

Careful not to change to much at once. Quality of replacement parts are questionable these days and will cause you to fall into a rabbit hole.

I dont know what a v6 standard psi rail pressure should be. Interweb claims 38-41psi.

Maybe someone will chime in soon

 

[HennessyDC]

Thanks.
Its had very little upkeep far as i can tell.
That was about what i was able to find too, 30-45 psi, with "sweet spot" about 38-41 like you said.
Using Motorcraft, when possible. Looking into inginition coil pack, ford told me it was discontinued. Im getting spark to all plugs so no big there.

 

[96blak54]

Ford started adding electronic fuel pressure sensors on the fuel rails. Im not familiar with the v6 engine and location of sensors, but i can tell you them fuel psi rail sensors can give you a hard time.

 

[HennessyDC]

Ok. That seems like maybe a thing. Pump primes, starts no issue, regulator works, 28 psi just seems like itd be too low.
ill do a dive into the sensors. thanks.

 

[shovel]

the job of the regulator is to maintain continuous pressure across the injector, remember the other end of the injector is in manifold vacuum so it might be 28psi vs. the atmosphere but it's still ~38psi vs. the place it's squirting.