Fuel pressure

[ropinwillie]

What should the fuel pressure be when you check it and if you don't mind telling me how to check it that would be great. I'm not a complete dumbass when it comes to working on it but this is my first Ford v6

 

[RonD]

Welcome to TRS

Look on the intake and find the fuel injectors, they are connected to whats called the Fuel rail, it supplies them with fuel
The fuel rail will have a test port on it, usually on passenger side of a V6
Test port "looks like" the air valve on a tire, because that is what it is, a Schrader Valve, it may even have a cap on it like a tires air valve, unscrew it, nothing will come out, same as tires cap

You screw on a fuel pressure tester and that presses the center pin in so you can read pressure in the fuel rail

Fuel injected Engines running pressure for 1985 to 1997 Ranger is 30-35psi

Also on the fuel rail is the Fuel Pressure Regulator(FPR)
FPR has the RETURN fuel line and a Vacuum hose attached
With engine running you want to unplug that vacuum line, and make sure no gasoline comes out, lol, and also see if fuel pressure goes up to about 43psi

Put vacuum hose back on

Pressure should drop back to 30-35psi

Shut engine off key off
Watch if fuel pressure drops, it should go down to 20-25psi and stay there, basically for a year or two, long time

If pressure drops to 0psi then either the check valve inside the fuel pump is leaking, or the FPR is leaking
Or a fuel injector is leaking but.................engine would run poorly and MPG would be about 5mpg, lol

If pressure is 0psi, cycle key on and off 1 time, should see about 10psi, cycle key again and should see 20psi, ect...it will top out at 43psi or whatever FPR showed with engine running and no vacuum line attached

The fuel pump only runs for 2 seconds with key on, that's a safety feature, so you have to cycle the key on then off repeatedly to build up pressure again if its leaking down to 0psi with engine off

1998 and up Rangers use 55-60psi fuel pressure and no RETURN line, FPR is inside the gas tank with fuel pump

 

[ropinwillie]

RonD, Thank you for the reply I will definitely try that.

 

[PetroleumJunkie412]

1998 and up Rangers use 55-60psi fuel pressure and no RETURN line, FPR is inside the gas tank with fuel pump

Damnit Ron, now you tell me...

Just had the tank out, didn't know there was a regulator in there.

Got a part number for one for 2011?

 

[RonD]

Damnit Ron, now you tell me...

Just had the tank out, didn't know there was a regulator in there.

Got a part number for one for 2011?

Not a "sold separate" part as far as I know, its on the fuel pump assembly, seen here: https://images.carid.com/tyc/fuel-pumps/150313.jpg

It's the round disc on right side of the unit
It's connected to the "return" line on the fuel filter, the 3rd port on the filter is a Return line: https://ic.carid.com/fram/items/g9343_6.jpg

Ford switched many of their models over to a Fuel Pump Driver Module(FPDM) in the mid 2000's but not the Rangers, we also never got "drive by wire" throttle plates, lol
FPDM eliminated the need for return line and FPRs, FPDM could vary the voltage at the fuel pump based on engine demand
But there were many failures of the FPDM units

 

[PetroleumJunkie412]

So. Say I knew this guy that just changed the actual pump, and re used everything else.







And put a 340lph pump back in said factory jig

 

[PetroleumJunkie412]

Not a "sold separate" part as far as I know, its on the fuel pump assembly, seen here: https://images.carid.com/tyc/fuel-pumps/150313.jpg

It's the round disc on right side of the unit
It's connected to the "return" line on the fuel filter, the 3rd port on the filter is a Return line: https://ic.carid.com/fram/items/g9343_6.jpg

Yep yep. Saw that little guy right there.... Thought to myself "nawww who would do something like that?"

 

[RonD]

So. Say I knew this guy that just changed the actual pump, and re used everything else.







And put a 340lph pump back in said factory jig

That would be fine, just more fuel would return at idle, and I assume "he" needed more fuel flow at higher RPMs so the higher LPH was needed, so FPR would just keep pressure at 55psi regardless

 

[PetroleumJunkie412]

Wait, thought 2011 was return less?

 

[RonD]

1998 to 2011 are "returnless" except they are not really, lol, they just have the return line at the filter instead of at the fuel rail where it was, WITH the FPR, from 1985 to 1997

 

[PetroleumJunkie412]

1998 to 2011 are "returnless" except they are not really, lol, they just have the return line at the filter instead of at the fuel rail where it was, WITH the FPR, from 1985 to 1997

I UNDERSTAND THINGS NOW

THANK YOU, GOD

 

[RonD]

LOL

Only real way to do returnless with fuel injection is with the FPDM type setup, i.e. variable speed fuel pump operation

 

[PetroleumJunkie412]

And that explains the chebby bros grabbing the E89 series pumps out of BMW....

 

[sgtsandman]

That also explains why the back side of the fuel filter has two nipples.

 

[PetroleumJunkie412]

That also explains why the back side of the fuel filter has two nipples.

I have two nipples and no filter.