Ford Truck Enthusiasts Forums - how do dual gas tanks work?

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how do dual gas tanks work?

I ran a few searches, but kept getting hundreds of threads. The ones I read were about repairing or troubleshooting them.:-X15

I got this crazy idea of putting dual tanks on a truck. I know where to mount both tanks (I think) and which will fit in there (again-I think). More research and final measurements will be needed still. They will have the factory sending units and pumps in them (will be used).

I wanted to find out "how it works" before I go a lot further into research and locating parts.

How do the factory installed one work? My dad's 88 f-150 has a flip switch that goes from one tank to other (gas guage reads whichever tank you are on).

I am guessing both tanks feed into a control valve somewhere? The dash switch controls a relay that moves the valve and changes the electrical circuit to the guage?

Where are these things mounted typically? Anyone have a wiring diagram/fuel circuit diagram or know where I can find one?

Any help would be appreciated. I truly know less than nothing about these.

Thanks everyone,
Brian

both tanks feed into a selector valve . you can flip the switch to select between tanks.

If you don't want to screw with the electronics, you could use a valve like the one on my old Bronco. You manually rotate the valve to get gasoline from the tank you want to use.

Thanks guys,

I still don't know how ford has it set up, but I did find a valve at jc whitney (would never use it) after you told me there was such a thing.

Here is the info: <TABLE cellSpacing=0 cellPadding=0 border=0><TBODY><TR><TD vAlign=top width=530>******** language=javascript src="/media/jcwhitney/jcw/javascript/backToCatalogRFX.js;pvad2581d3e2641e8d" type=text/javascript></SCRIPT>
POLLAK® MOTOR-DRIVEN FUEL TANK SELECTOR VALVE

<DL>For fuel-injected systems operating up to 65 psi. Designed to prevent returning fuel to incorrect tank. Weatherproof fiberglass-reinforced nylon valve body. Valve grounds to frame. Meets or exceeds DOT standards. Fits 3/8" I.D. fuel hose. Recommended fuse: 10 amps. Can be wired so original dash gauge indicates fuel level in either tank. Includes: switch, faceplate, wiring connector, instructions. Hoses not included—order separately. 6-port valve required on vehicles with 3 lines attached to fuel pump. For 12-volt systems. </DL><DL><TABLE class=appChart cellSpacing=0 cellPadding=0 width=409 border=0><TBODY><TR class=odd><TD class=tableCell align=middle width=42>Kit</TD><TD class=tableCell align=left width=26>ZX812705U</TD><TD class=tableCellPlain align=middle width=67>$53.99
</TD></TR></TBODY></TABLE>
</DL>

</TD></TR></TBODY></TABLE>
If I can find out more about the ford parts/wiring, I guess I will try to find one. My idea is not sounding so crazy now (to me anyway).

Okst1: I remember seeing one like that in an old ford when I was a kid. It seems like it was mounted under the edge (or end) of the seat? A lady ran our of gas on one tank and we almost never got it started again on the other. What memories! :)

As far as wiring...I hope to transplant a whole EFI system in. If I can do that (I hope I can), the valve will be easy. :-X16

My '86 (EFI) just relies on which in-tank fuel pump is running. The wiring is in the switch for the pumps and the senders. I don't seem to have a 'selector valve'.

Maybe I'm missing something?