smithbr67

I recently bought an F150, 2WD, 4.9l six with dual tanks. One tank has a tiny leak. Can that tank be excluded? I mean, can the faulty one be closed off so it will not fill with fuel, and run the truck only with the one good tank? I have been told when you put gas in the truck both tanks fill simultaneously. I want to close of the bad tank from filling and draw fuel from the good tan only, until I can get the tank fixed. Any ideas? Thanks.

MONSTERPRE

I Don't believe that if you put gas into ONE inlet of the TWO filler lines you fill both tanks...each tank has it's own filler. I think you are talking about the "return line" from the fuel rail located around the intake manifold.

I'm sure someone here with more Tank knowledge can help you figure out how to either fix your tank for a very low cost, or how to disconnect it and keep fuel from entering it through the return line.

1987 F-150 XLT 4x4

If everything is working as Ford designed the Dual Tank System,
unless you switch to the tank that has the leak,
the fuel will not come out of it or return to it.

I've heard of people who had problems after they disconnected
and permanently removed one of their gas tanks.

If the Tank Selector Switch is malfunctioning or the Fuel Tank Selector Valve is bad,
then gas will be returned back to the wrong tank and actually overfill the tank and gas will run out the filler cap.

1990-96 F-150's have a 6-port Fuel Tank Selector Valve.
The 6-port Fuel Tank Selector Valve located on the frame rail between the tanks and the filter.
The 1990-96 F-150 with dual tanks have a High-pressure fuel pump in each tank only.

The 1987-89 F-150's have a reservoir located on the frame rail called
Dual Function Reservoir.
The 1987-89 F-150 with dual tanks have a Low-pressure fuel pump in each tank
and one High-pressure fuel pump located on the frame rail before the fuel filter.

www.LMCTRUCK.com

LMC has aftermarket Gas Tanks for sale.
If you ask; LMC will send you a free catalog.

Hope this helps!

93 Flairside

just go to pick and pull and get a tnk for a few bucks and put one on. and yes you can just run it off of only one tank

gushaman

OK i just got this 88 f150. the genius who had it before me, replaced the tank selector valve with two fuel filters, one of which is leaking (can the be put on backwards???) so as to bypass the rear tank, which needs a fuel pump (supposedly) I want to replace the pump, and possibly do the bronco tank mod, and will need a selector valve. I am having a hard time figureing out whether i need a motorized one or not. should there be a bundle of wires for a motorized one already under there?

Just call me Sean

iTrader: (1)

No wires the factory one is mechanical.

toreson2000

i have a 19905.0 4x4 both tanks work but the sending unit on the front tank has never worked always reads E but the pump works on it so i just use the back tank i keep about 5 gallons of gas in the front one just to keep the fuel in there so i gun the pump about once a week to keep it from going all the way bad the sending unit is like 150 and the full pump and sending unit are like 200 crazy!

oldsmoboat

I just bought a 94 and it has a small hole in the front tank. I plugged it with some JB Weld Stick and it's held up for a couple of weeks so far.
A new tank is about $85.

rcbartel

I have a 1991 F-150 4.9L inline 6 cyl., and the front tank was leaking so the shop removed it and put a fuel filter inline somewher in a return vapor line (?), and now it is hard to start and once running seems to run ok. Where can I get instructions on what fuel lines need plugging, routing, t-connect, or clamping if the front tank is permanently removed? Will anything else go wrong other than hard starting, such as too high fuel pressure, incorrect vapor return pressure or routing, etc. etc.?? Call me at 410--903---2759 or rcbartel@yahoo.com

rebeljeb

In 1990 Ford f150 began putting fuel delivery modules (FDM) in each tank of dual tank models. Each FDM has its own fuel pump (electric), fuel reservoir, supply check valve and most importantly the SHUTTLE VALVE SELECTOR. It has ONE line of fuel flow TO engine and ONE line of fuel flow FROM engine. The only thing on the rail is a in-line fuel filter on the supply line going to the engine. Having said all that, they've had a lot of problems with these FDMs. Overflowing tanks due to selector valves not closing properly (stuck open). They recommend replacing the FDM on the tank that is overflowing. I just did that on my 1990 model (rear tank) but it didn't help. I'm thinking I have to replace the FDM on the other tank (front). I think the selector valve on the front tank is stuck closed. Would really appreciate any input on this anyone has. Its ok to call me a dumbass, I can take it. I just want the right info!