F150 Dual tank problem

[TweetyDee]

I recently purchased a 1991 F150 with a 6 cyl eng. and auto trans. Back tank had gas, but needle said empty for front tank. I "filled" the front tank (only took 9 gal.), and it still says empty. I switched over to the front tank and the truck will not start. Obviously there is no gas getting to the engine from the front tank. Are there two fuel pumps for these trucks (one for each tank)? Are there any other part malfunctions that would be causing this problem. With the price of gas in California, I can't afford to waste 16 gallons! I appreciate any suggestions.

[armstrong]

I believe there are two seperate pumps. One for each tank. My buddy had a similar problem and i think he fixed it by replacing the pump or its harness. I will check with him and get back to you or maybe someone else knows.

[gumby_ct]

Each tank has its own pump & sending unit. I would also be wondering if it could have water in it. Good Luck.

[IHI]

Originally Posted by gumby_ct

Each tank has its own pump & sending unit. I would also be wondering if it could have water in it. Good Luck.

Truck has pump in each tank and sounds like that is your problem...I'be gone through 3 pumps in front tank and 1 in rear tank. Say away from O'reilly or Advanced aut type replacement pumps-junk. Go to Napa and spend the little bit extra and you'll be much happier. Typicall $128 per pump and I have'nt had trouble since switching to Napa brand-OEM wanted $453 for each pump and that's too much for an old road whore so napa it was

When getting the pump, get a good set of fuel line disconnect tools to undo the fuel lines, aftert all these pumps I've got it down to a 30 turn around science, but expect to spend hr start to finish-not hard, just dirty and heavy since you have a full tank

[matt500]

my 1989 ford did same thing it was the fuel selecter switch. as for the gage i would have to say you need a new sending unit in the tank.there are three fuel pumps one in each tank low presshere and one on frame rail hope this helps

[Dave34720]

I had the same problem on my F250. I replaced the front pump and sending unit in tank. The truck now runs fine. I have to agree with IHI. NAPA pump is a little more expensive but works great. It has a good warranty - if it doesn't work, just send it back and they'll give you a new one. Good luck!

[hazy303]

I would say to siphen the gas out of the tank to do the repair, then you can use the gas now, until you get the new pump. When you turn the switch to the front tank and turn the key to acc(just before start), do you hear the front pump prime? Listen for the back since it is working, you should hear a hum. Maybe get a friend if you cant hear to listen while laying on the ground.

[mechhound]

Through 1989 the F-series fuel-injected trucks had a pump in each tank, plus a high pressure pump in the frame rail. Starting in 1990 they just put a high pressure pump in each tank and omitted the frame rail pump. The past statements believed to be true in all cases, but not guaranteed.