Can someone explain this factory fuel pump assembly?

[bobbywalter]

it keeps the vapor pressure down in the system for less emissions.

 

[Dirtman]

Damn government! Stay outta my fuel pump!!!!

 

[Dirtman]

Physics mostly. Also accountants.

The fuel is used to cool the pump. Fuel returning from the engine is hot. Fuel that doesn't make it to the engine is less hot.

That's the reason for a returnless fuel system. The reason for the mechanical returnless is that is was cheaper to build than the electronic returnless system.

The mechanical system just has a pressure bypass in the filter. The electronic one needs a pressure sensor, wiring, and often Ford used a seperate driver module, which all adds up to money.

Wait then this still doesn't explain the return line at the filter... my filter has 2 lines in, one line out. So for some reason the filter itself has a bypass to return fuel back to the tank. The regulator is already on the pump returning excess pressure back to the tank, so what purpose does the filters return line serve on the frame rail.

 

[adsm08]

Wait then this still doesn't explain the return line at the filter... my filter has 2 lines in, one line out. So for some reason the filter itself has a bypass to return fuel back to the tank. The regulator is already on the pump returning excess pressure back to the tank, so what purpose does the filters return line serve on the frame rail.

The pump will still produce excess volume because it runs at a constant speed, but fuel consumption isn't constant across the RPM range.

 

[bobbywalter]

Wait then this still doesn't explain the return line at the filter... my filter has 2 lines in, one line out. So for some reason the filter itself has a bypass to return fuel back to the tank. The regulator is already on the pump returning excess pressure back to the tank, so what purpose does the filters return line serve on the frame rail.

The ones I have worked on that are this style, the return line goes thru the regulator....this maintains pressure and volume and minimizes vapor pressure due to heat soak and airation...and vaporlock.

The way I am reading your questioning of this.....your saying you understand it as the regulation is on the pump side before it even leaves the carrier.

Maybe some are....I don't remember seeing it that way...so maybe I am wrong. I don't know how the fawk that would work....you would need a super pump.

 

[adsm08]

The way I am reading your questioning of this.....your saying you understand it as the regulation is on the pump side before it even leaves the carrier.

Maybe some are....

I think the 98-01 ones were this way. IIRC the 98-01 Rangers used a returnless system with a single port filter and a regulator in the tank. Not sure why they changed it.

 

[RonD]

They changed it because it didn't work very well, I think pressure in those years was 65psi but it would often drop to 50psi, later models, with return, would settle in around 55psi, so more stable pressure for PCM to deal with

Ford did switch to FPDM(Fuel Pump Driver Module) in the mid-2000s on many models, it varied the voltage to fuel pump, and I think they finally added a fuel pressure sensor
Rangers never got this
FPDM system has no return, but there were problems with it in the beginning

 

[adsm08]

FPDM system has no return, but there were problems with it in the beginning

You mean like the holes that rot in the aluminum housing because some dummy put it right against the steel frame?

 

[Dirtman]

My pressure on my 09 is 65psi with the 3 port filter.

 

[bobbywalter]

Yeah. Didn't like the mark 8 setup either

 

[bobbywalter]

My pressure on my 09 is 65psi with the 3 port filter.

I bet when your not watching it.....it goes to million. And north Dakota is visible from niburu.

 

[RonD]

My pressure on my 09 is 65psi with the 3 port filter.

It will drop to 55psi when you get your new pressure gauge
Use it to test your tire air pressure, if its 45psi then its reading a tad high

LOL, while the actual pressure does matter, its more about a steady pressure so PCM will know how much fuel will flow out of each fuel injector when its opened for say 100milliseconds
10-15psi swing, while running, is a bit much

65psi is fine as long as if stays 60-65psi while driving