This weekend I'm going to try and figure out why the old green turtle's front gas tank won't pump. (1995 f150 6 cyclinder with only 213000 miles)


QUESTION-Do I have two relays or only one for both tanks? What's the most likely place to start the Search??


Thanks for reading and I appreciate any advice???

John

 

You should only have one relay for both pumps. Pull the electrical connector at the front fuel pump and see if you have any power to it. If you do, the pump is probably bad and needs replaced which means you'll have to drop the tank.

 

There is also an electric solenoid where the lines from each individual tank combines into a single line up to the engine. The solenoid is controlled by the dash on the switch, and if it goes bad it will freeze on one tank or the other. You can test this by simply bypassing the solenoid with a brass coupling from the front tank fuel line to the main fuel line. If the truck runs, your fuel tank selecting solenoid is probably bad.

I've had to replace them in the past, especially in salty climates, or areas that salt the roads heavily. I don't recall it being too expensive.

And welcome to FTE!!!

 

i have a 94 xl with a 6 cyl 288,000 my front tank is missing real bad on the front tank. i just replaced the fuel pump today and its still doing it. it will start missing on the front tank so ill switch up to the back tank and the idle clears up but if i go back to the front tank in about 3 min it still start hesitating, spitting and sputtering.

what else could it be????


dont mean to hijack your thread but our problems are similiar so i figured id jump in

 

i thought the dash switch just energized either pump when selected.. didnt think there was any kind of solenoid or at least thats what ive been told about my 94

 

No there is not a solenoid selector valve in the 90-96+ gas trucks.

chrismartinez0,
You are correct.

 

You may have a pinched fuel line or a bad fuel (gas) cap.

 

ok ill swap gas cabs (front and rear) and poke underneath there looking for a pinch line and ill get back to ya, subford....thanks for all the help

 

ok swapped gas caps and followed the gas line from the tank up to the engine...nothing. could i possibly have a collapsed fuel line? the fuel filter is only a couple of months old too so i dont know what to check next. is there a way to take off the fuel line at the manifold and somehow run the fuel pumps to check for output? i know the back tank is good, so i could just compare it to the front tanks output..

 

Sure just put a fuel pressure gauge on it and tape it someplace where you can see it and take it for a ride and switch tanks and see what happens.
It may be a bad fuel pump and you will have to take it back.
The only other thing that comes to mind is a bad selector switch.

 

There should be a connection at the back side of the engine bay where the fuel lines coming from the tanks connect with the fuel rail. You'll need a fuel line disconnect tool to take it apart.

Something else to consider is that some crud from the tank has clogged up the strainer for the fuel pump inside the tank. It may just be a matter of pulling the pump and replacing the strainer.

 

i just put a brand new fuel pump and strainer today... so i dont think its the pump or strainer....as soon as i got the new pump on today first crank, switched it to front tank and within 3 minutes it started doing it?????

 

If I'm understanding you correctly, you've replaced the pump twice now, correct?

If that's true, then it's got to be something electrical or there's some kind of blockage in the fuel lines, be it crud or a collapsed line. I don't really see how the line could collapse at all since it should be made of steel. I find it more likely that it could be broken somewhere and is leaking fuel.

If you can find a large piece of cardboard, place it underneath the truck and switch to the front tank. Then get down and start looking for drips. If you see any, check to make sure that it's gas. If so, then there's a break or leak in the line somewhere.

If no leaks are found, then it has to be electrical.

 

I haven't started pulling things off yet, but I have studied the underneath and my lines to determine what might be cause my front tank to not deliver fuel.

1. Could be the selector switch
2. Could be crud blocking the fuel line from that tank.
3. Could be a faulty pump.

Does these seem plausible points of attention for me?


My fuel filter looks pretty old so I'll switch it out any ways. I can't remember even having it changed.

Thanks

John

 

Both tanks use the same fuel filter.
Pressurized fuel lines do not collapse.

1. The selector switch could be the problem, jump around it on the power wire going to the front tank and select the front tank and see what happens. The wire to jumper is the Red to the Red wire with a yellow stripe. See diagram below.

2. Did you look in the tank when you replaced the pump? Was it clean?

3. Some have replaced three bad pumps in a row and demanded a better pump and was then give a different brand pump and the it worked.



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