Fuel Pump Flex-vs-Gas-Need Help!!

[Raynman]

Ok...long story short. I had a backup fuel pump to use on my 99 ranger 3.0 flex fuel VIN "V" But it was from a junkyard fuel tank I had to replace 1.5 yrs ago. I only used the tank with my original fuel pump. My fuel pump died last Saturday...so I pulled the bed off,and swapped the pumps only ( not entire unit, with sender...etc.) Got fuel pumping...so replaced new filter and ran the truck. Engine lopes at high speed revs. idles fine, and can push pedal halfway...runs ok. But at hi revs...engine lopes (HI/LO HI/LO) I am pretty sure the junkyard pump is a Gas unit..(not Flex fuel) I am going to check the rail pressure tonight with fuel press. gauge. Does a gas pump not run right with a flex fuel vehicle?? mixed answers out there on the info. super hwy. Please help me from throwing the wrong parts at my Mighty Ranger!!!

 

[Earl43P]

I just searched RockAuto.com for you, Flex and Gas use different part number fuel pumps.

Flex pumps are expensive.

I can't tell you why they are different, but maybe one of the Ford techs knows and will reply later.

 

[killj0y]

maybe viscosity is different, but otherwise a pump is really just a pump. Maybe one is weaker than the other?

 

[adsm08]

The biggest difference between most Flex and gas fuel system components is that Flex stuff is made from stainless so that they can stand up to the corrosive effects of the alcohol.

I can only see running a standard gas pump as a problem if you are actually running high volume ethanol fuel. It's probably just the same as any other used part, it was probably already broken when you put it in.

 

[Raynman]

fuel pump Flex...

I am leaning that way...toward buying the Flex Pump Only. I tested fuel pressure tonight.....KOEO 56 psi but dropped to 20 after 1/2 hour Key off.
Pressure seems to drop slowly after key is turned off. Started engine and let idle. Prussure holds @ 56 psi. This appears to be lowest range in the spec I found (64 PSI +/- 8 PSI) the pressure does not hold at all. It will drop to zero eventually 1/2 hour plus. My rail seems to have a FPR on it. Do these fail? How to test em? I am thinking of a new pump and then test again. Am I missing anything?

 

[Earl43P]

Your FPR is part of the Sender assembly.

That item on the fuel rail is a damper, not an FPR.

Your leaking pressure down could be a number of things.
Run some SeaFoam through the gas tank and maybe it'll clean out a seeping injector for you. The other likely leaker is the checkvalve (part of the pump itself).

Putting a new Flex pump in it will fix that.

 

[Lucifer sam]

E85 requires more fuel volume to make the same horsepower as regular pump gas, its probably a better flowing higher volume pump

 

[Raynman]

new pump....

"The other likely leaker is the checkvalve (part of the pump itself).

Putting a new Flex pump in it will fix that. "

I was trying to replace the pump only ($187) ass opposed to the wole pump/sender unit.($400+) I will see if I can buy the checkvalve seperatley.
BTW the Part on the fuel rail does have a vacuum line on it. So it looks like an FPR...???

 

[Earl43P]

The check valve is an integral part of the pump, not a separate component that you can replace.

 

[Raynman]

Repair Complete!!!


Went to a pick-n-pull in Stockton, CA 2 more fuel pumps to scavenge parts from. Replaced check valve. And Viola!! pressure never dropped below 40 lbs.
Thanks, for all the input.!!
BTW Pick-n-Pull has a great system for inventory and vehicles all on welded tire rim/stands. My hats off to them for running a pretty tidy operation!