Electronic Fuel Switch

[jesilvas]

So I've got a 100 gal tank in my bed for the tractor but mainly just to have in case of whatever. I was wondering if it would work if I plumbed BOTH fuel tanks on the truck to the same fuel pump (OEM or aftermarket, doesn't matter) and just have a switch so I can decide where I wanna pull the diesel from.
And also if I could get a gauge to figure out how much diesel I have in the big tank in the bed.
Just tired of stopping and filling up with the hose out of the big one

[JSchuricht]

Yes you can, I have my 150 gal hooked up that way. You have a few options for the hookup, but your basic supplies are 3/8" diesel rated fuel line, 5/16" diesel rated fuel line, 12+ hose clamps, fuel selector valve, SPDT switch, wire and a inline screen.

WARNING: The screen is extremely important to protect the valve. Otherwise, you may end up like me where a small piece of plastic finds its way into the valve, jamming it so fuel is drawn from one tank and sent to the other causing a overflow and visible trail showing where you have been.

The stock setup has a feed and return line, so you either need a 6 port valve or two 3 port valves. If you have an Air Dog or FASS, you will need one additional valve.

The simplest setup would be with a non serviceable valve like a 6 port Pollak. The Pollak valve is somewhat inexpensive, has the ability to switch the wire for the sending unit automatically and stays in the last position when power is removed. The disadvantage is you can't take it apart if it gets jammed.

Another option would be a serviceable valve like this 6 port Greasecar unit. It is spring loaded so it will return to its default position when voltage is removed and it can be dissembled to remove debris should it get clogged. Disadvantages is EXPENSIVE, dose not switch the sender, so you will need a little extra wire.

The basic setup is to cut out a few inches of the feed and return line on the DS frame rail. Insert valve in between cut, plumb in aux tank. Intersect the yellow/white wire for the sender. Mount switch in cab and supply 12v and ground.

Note: if you switch tanks while the truck is running, it can take about 20 min for the gauge to move from Empty to Full.

[jesilvas]

Well ok then.
For the Pollak it says for use in application that have an in tank pump and these trucks don't have that. And the stock setup does have a return? I've never really looked at it so I'm not sure.
If I'm gonna do this, I was gonna add in an Airdog probably and then a regulated return kit from ITP. So with just the stock tank, if I'm thinking correctly, line from tank to pump, line to fuel bowl (or regulator if I delete it), then to fuel rails on heads or return to fuel tank. Then of course I'd have to return it to whichever thank it was coming out of right?
So wouldn't I just need one switch between the two tanks and the pump to decide which tank to pull from then one (wired to the same in cab switch) between the engine and two tanks to send it back to the same one?
Sorry I've just never really done anything like this but would love to.

[JSchuricht]

I would hold off until you have the ITP RR and AirDog so you can do all your plumbing at once. The AirDog has its own return for the aerated fuel which dumps into a T in the filler. So you will need 3 valves, one to switch the supply, one for the ITP RR return and one for the Air Dog return. There is a return from the fuel bowl if you don't get the RR.

I would have used the Greasecar valves for all three, but my tank came with a Pollack which I dedicated for the return lines. I have been running it for about a year without issue, but didn't know about the in tank pump requirement. They must have intended it for pressure rather than suction.

Hear are some pics of my plumbing mess with AirDog and ITP RR.

[jesilvas]

Originally Posted by JSchuricht

I would hold off until you have the ITP RR and AirDog so you can do all your plumbing at once. The AirDog has its own return for the aerated fuel which dumps into a T in the filler. So you will need 3 valves, one to switch the supply, one for the ITP RR return and one for the Air Dog return. There is a return from the fuel bowl if you don't get the RR.

I would have used the Greasecar valves for all three, but my tank came with a Pollack which I dedicated for the return lines. I have been running it for about a year without issue, but didn't know about the in tank pump requirement. They must have intended it for pressure rather than suction.

WOW! It's like you've done everything to your truck I've always wanted to do.

Yea I forgot about the return on the AirDog.
So there is a return from the fuel bowl? Didn't know that.

This is in the future of course and I DEFINITELY was planning on getting it all together before I did anything. I can work all the plumbing and wiring, that's for sure. Just basically wanted to see if it was at all possible and a basic idea how to go about doing it.

Here's a quick drawing I did. Is this basically it?

[strokin_early_99]

According to DOT / CFR 49, you can not alter the factory fuel system hence why transfer-flow(and other aux tank mfg's) will only design a system to plumb a pump from the aux tank to the main tank and not into the fuel system. I had my system inspected at the local truck scales since I travel to Canada occasionally and man did I learn a lot.

Just make sure you do everything legal or if you get in an accident and there is a fuel spill or fire issue, you will be in deep kimchi.........

[jesilvas]

Originally Posted by strokin_early_99

According to DOT / CFR 49, you can not alter the factory fuel system hence why transfer-flow(and other aux tank mfg's) will only design a system to plumb a pump from the aux tank to the main tank and not into the fuel system. I had my system inspected at the local truck scales since I travel to Canada occasionally and man did I learn a lot.

Just make sure you do everything legal or if you get in an accident and there is a fuel spill or fire issue, you will be in deep kimchi.........

That is right. I completely forgot about that part of it. Dang.

Maybe if I added some valve that cut fuel flow unless the pump was on?

[strokin_early_99]

My 55gal aux tank is setup to gravity feed into my main tank. I have a roll-over valve in the filler neck of the truck with a ball valve on the tank and under the truck for full isolation. I also have an inline filter between the aux tank and the truck tank.

[jesilvas]

So does the roll-over valve keep it from over filling?

[strokin_early_99]

Not really , it is designed to keep it from leaking out if the truck rolls over. If your tank is sealed it will fill up all the way and the main fuel tank sees a full tank for +500 miles. Then once the aux tank is empty or you shut it off, the fuel gauge will show below full as the fuel is used. I love mine. I have the kit from RDS and then added a separate valve under the bed of the truck and a filter as well.