Ford dual tank silliness

[viven44]

Best I can find is that they are under the drivers seat. The floorpan of the early bronco was probably a different animal altogether. I think it would be best to make it your own on the bullnose. While you are at it, I would also install a 3 way toggle switch right by the valve to switch the sending unit. The switch should route to into the selector valve harness right below it to switch between front and rear sending units. If you come up with something that works well, I'll copy it. My setup while requiring crawling has given me peace of mind. I still have the Pollak valve in mind very much, on a future truck or future timeframe on this truck I would consider it as well.

[Nothing Special]

If you missed it I posted a picture of the valve in my '71 Bronco on the previous page

[ArdWrknTrk]

Doh!

I should have said senders

Stock, they all come up to the dash ground by the radio

[Ifitaintbroke]

Ooh that twin stick setup looks gooooood!

[myrl883]

ArdWrknTrk wrote

Ready for the zombie apocalypse???  

Some setups have the senders switched at the actual switch in the climate control.
You could find that p/n and just run the wires.....  💡

That's how my '85 was. The switching valve had ONE wire to it. It was a simple spring loaded solenoid valve.

[Ifitaintbroke]

Here is my setup:









The only components needed for this setup is 2 Standard FV-1 fuel valves, a 5 pin Bosch-style relay, and 1 wire. Other than that 1 wire, this setup uses only factory wiring. No need to rewire or open up the main harness. The factory switch is retained, and, AFAIK, any variant can be used. I'll try to find my diagram of it, as the pictures don't explain how it works. For now, I'll try to explain it simply.

The connector from the fuel tank selector switch in the cab is disconnected and set aside. I taped mine up and ran a separate switched power wire. The switch is then used as an "on off" type switch. Mine is a 6 pin, but only 2 will be used. I set mine up so that when the switch is set to "rear" continuity is broken. This sets the rear as the default tank in case of a malfunction. The front could be used in the same fashion. The power wire goes into the switch, via a 1/4 inch terminal, and back "out" the same way. You just have to figure out which pins to use. The power wire is then routed underneath the truck to the fuel valves and relay. It goes to the relay's switching terminal, and then to the fuel valves via the ground pin on the relay. The valves are connected by a wire and are self-grounding so no other wire are required for this setup to work as far as physically switching the tanks. I hope I'm explaining this well and not being confusing! When I say in and out I mean like you would see in a schematic. I'll have to draw one up to make this easier. I'm out of time right now so, but you get the gist of it. I'll write up the gauge side of this later.

[ArdWrknTrk]

I'm trying to wrap my head around how this is in any way advantageous over just using the proper Pollak valve, for $80 delivered?

Yes, you need to splice their pigtail to the existing harness, but since the factory valve is over $400 and NLA I don't see a downside.  

[viven44]

Really professional installation!!! Well done.

If I had to nitpick something, it would be that the relay should be sloped down just a hair. Just in case moisture accumulates inside. It may be sloping down already but can't see it well.

[viven44]

The only advantage I can think of is that the factory valves are known to cross-flow. My rear tank overflowed once because the valve was stuck such that front tank's return ran into rear return as the internal o-ring was shot (maybe?). This setup looks like it prevents that issue.

[ArdWrknTrk]

I haven't had a problem with any replacement Pollak valve, diesel or gas. (though they were the ones that made the original valves for the Big Three)

I haven't used one recently and don't recall when SMP bought them out.
Maybe the newer ones are not as good (China) 🤔

[Ifitaintbroke]

The main reason I did this is to do away with the factory wiring, not the valve. This truck almost 40 years old, and the wiring was junk when new. This system has 5 times as many wires as necessary, and the wires themselves are (in my opinion) too small. Then consider the connector under the hood that are prone to corrosion. Basically I ended up doing this because nothing else worked. This came out of 2 YEARS of trying to fix the factory wiring. I got fed up.

[Ifitaintbroke]

I hope that is the case. If one valve malfunctions, it should break the circuit and the other valve will return to its resting position.

[Ifitaintbroke]

The advantage is the single 14ga wire that operates it. And that's a good point of the relay, I might turn it down a little.

[ArdWrknTrk]

I can definitely understand being fed up but I have to disagree that the wiring sucked when new
I bought my truck with less than 10k on it in '88 (because the guy wanted EFI) and I'm still on my original valves and wiring.
I don't think inv ever had to touch it.
(But I do have a mechanical pump, so only senders through my 6-port switch valve.

[Ifitaintbroke]

That's very impressive and surprising Jim. But, yours is the only one I've ever heard of that still works. I deal with these trucks (and the later ones) almost daily and I've never seen one with a working dual tank system. Most of them have been running on one tank for over 20 years. Idk, maybe it's just our humidity down here!

[ArdWrknTrk]

Why would someone go to get parts If everything is functioning correctly?

'm kinda surprised with all the salt and mag chloride on the roads up here.
But, as they say, don't mess with success.

[Ifitaintbroke]

True. My truck originally was sold in Colorado, and has some evidence of slat on the frame, but thankfully the body is solid.

[Ifitaintbroke]

Rear unit is in. Clearance is tight, but I think it will work. Will definitely be careful putting the bed back on. IDK, this truck would probably look good as a flat bed!

[ArdWrknTrk]

Super clean install Bradley!  

[Ifitaintbroke]

Front unit is in and now the real fun begins: the harness. Truth be told, I enjoy making wiring harnesses. Most probably see it as tedious and boring, but to me it is peaceful, quiet, and difficult to hurt yourself while doing. (Unlike removing that 18 horse B & S. I still have a big scar from that.)