Hey all...I'm new to the forum, new to the F150, in fact new to the whole world of trucks in general. I just yesterday got my first truck... a 1993 F150, 6-c, manual trans. It has the dual tanks and I'm completely confused about them.

First off, do I fill it up as normal? I tried to do so last night and it only took 13 gallons, but the needle didn't move at all. Do I have to flip the switch and fill it again? And under normal operation, when do I kick in the rear tank? Basically, I just don't know what's going on with it at all, and unfortunately neither did the guy that owned it briefly before me.

ANY help with this would be appreciated...

Jeff

 

u dont have to use both tanks. its just an option.
the tanks are about 17 gallons...if u really pack it in. if the needle doesnt move when u started it the gauge might be broken...try the other tank.

 

Hi i own a 93 f150 l6 4.9 auto with 308k duel tanks

fill the tanks up like normal front should be about 16 gal rear 17.5 gal

you can use eather tank when driving to swich tanks just flip the swich

if the fuel gauge dose not read bad gauge, bad ground on tank, the float in the tank might be filled with fuel and does not flote any more(both my tanks)

heads up if u one tank stays full and the other loses fuel u may have a bad pump

hope this helps

 

Two tanks; one switch.

If Switch says Front; it's using Front.
If Switch says Rear; it's using rear.

You can switch while driving. No problem. I agree; you should have 16-17 gals per tank

 

I second what those guys said.

I also have gauge problems with mine, I think it has something to do with some new fuel part (can't think of the name) that was put in there a few years ago. The gauge will say 1/2 like ALL of the time, until the tank has about 2 gallons left in it then it moves down to 1/4.

Also, my rear tank doesn't work, so I need to have that replaced (anyone know how much those cost?)

I have no idea how easily fixable the gauges are, I'll have to ask my mechanic next time I see him. It's really annoying having to estimate how much gas you have.

 

Hate to point out the obvious, but you never know- the guage will show the amount of fuel left in the tank you are using, not an average of the total fuel in both tanks. Also you need to fill up each tank individually.
I use the rear tank first, keeping the weight more centered, but that's just me.

 

You mean the fuel gages are supposed to work in these trucks?!?! I thought they were just for show! I just figured F150's were like motorcycles, in that your trip odometer was your fuel gage...

 

There are 2 gas tank-filling caps. One cap is close to the driver for the front tank and another toward the back for the rear tank. The tanks need to be filled separately.

The tank selector switch does 2 things. It selects which pump will get power and it switches the tank level indicator wires from tank to tank. When the front tank is selected the gauge wire from the front tank gets connected to the dash gauge.

If the front pump is on and supplying pressure to the fuel system, there is a check valve in the rear pump that keeps the fuel from flowing backward into the rear tank while the rear pump is off.

When you select the rear tank the front pump is off, the gas gauge wire is switched to the rear tank and the rear pump is turned on. With the rear pump on, the check valve in the front tank keeps gas from the rear tank being put into the front tank.

Should a check valve in a pump fail you will start to have fuel from one tank slowly fill the other tank as gas goes backward through the faulty pump/check valve.

I hope that this helps a bit.

 

hey I own a 93 F150 5.8L V8 and my front tank does not register as anything but empty but the rear one is fine until a quarter tank then it gets squirrelly but my question is do both tanks run on the same fuel leveling unit or is it two separate units

 

There is a sending unit in each tank.

 

1 each tank is like a separate entity.
2 the sending units in each tank supposedly only measures the fuel in each tank.
3 an open circuit on the sending unit will be displayed as an overfull condition on the gauge.
4. a gauge giving erratic readings on the gauge is either having the float in the tank hanging/sticking or the resistor in the switch going bad.
5. My suggestion is if you are not having fuel transference problems, then fill both tanks up, run one till it goes dry, keep mileage records, switch to other tank and refill the first tank so when the other tank runs dry you can switch back to the first tank , etc.
6. when you have problems with fuel pumps and have to install new in tank fuel pumps, you can change the fuel gauge float and sender switch when you change pumps.