Duel Tank Question

[TruckCo]

Yah it almost looks like from my second group of photos that pump may be connected to one tank if someone can help? Theres two ports on the tank selector and that blue line goes to one of them so i assume those two ports are each tank? Unless one is a return and one is a pump

 

[Grit dog]

There’s 6 ports on the tank selector.
Supply/ return from/to each tank. And supply/return to/from the engine.
you have to pull that cover off and trace the lines.
But if the outlet of the frame mounted pump goes to the engine then it’s pulling fuel from the valve and doing it for both tanks.
If the outlet of the frame pump goes to the valve and the inlet blue hose goes to the tank then it only works that tank.
Pop the cover, trace the lines, get a helper to switch tanks and turn the key on and off and it will be very apparent how it’s plumbed.

 

[SquareRoot]

That throttle body looks nothing like the PF2 I had unless it is a two barrel version.

 

[TruckCo]

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The blue comes from one of the two ports . The other port goes to the engine too so it looks like a fuel return and supply and not a seperate pump for one of the tanks. The other third line looks like a brake line

 

[TruckCo]

^^^^^ wait now theres 4 lines and one appears to be a brake. I didnt think there would be three fuel lines… im confused. Ill have to do more testing

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[Rumbledawg]

That throttle body looks nothing like the PF2 I had unless it is a two barrel version.

ya, it doesn't look like my throttle body either...it does look almost like a 2 barrel.
every pro flo i've seen is a 4 throater, but every thing else looks edelbrock all the way. maybe someone changed or used a diff throttle body, meaning it would have to be a pf2 or pf3 as there is no replacement throttle body made for pf1 (ask me how i know...)
Jay, you should have 2 feed lines to the valve and 1 feed line out, these 3 lines are 3/8's, 2 return lines to the tanks from the valve and 1 return line from the engine to the valve, these lines are 5/16's, and depending on how they ran the vent lines, these are 1/4'ers, 3 or 4 unless they've been "t"eed together.
just on the off chance your pump is going, it will start to whine loudly, like loud enough to hear while the truck is running.
this is how i have my selector plumbed, and ya, that 4th line will be going to your rear brakes

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[TruckCo]

ya, it doesn't look like my throttle body either...it does look almost like a 2 barrel.
every pro flo i've seen is a 4 throater, but every thing else looks edelbrock all the way. maybe someone changed or used a diff throttle body, meaning it would have to be a pf2 or pf3 as there is no replacement throttle body made for pf1 (ask me how i know...)
Jay, you should have 2 feed lines to the valve and 1 feed line out, these 3 lines are 3/8's, 2 return lines to the tanks from the valve and 1 return line from the engine to the valve, these lines are 5/16's, and depending on how they ran the vent lines, these are 1/4'ers, 3 or 4 unless they've been "t"eed together.
just on the off chance your pump is going, it will start to whine loudly, like loud enough to hear while the truck is running.
this is how i have my selector plumbed, and ya, that 4th line will be going to your rear brakes

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Awesome!!! So its normal to have three going to the motor? I guess that frame rail pump would be either on or off. I guess what i will do is run it on LH tank, swap the selector switch and see if that pump turns off. Then ill know of the pump on the frame is running both tanks or just LH. But from the Plumbing it looks like it would do both other wise id have more lines from what your saying

 

[TruckCo]

This also has 8 individual fuel injectors

 

[TruckCo]

Ok thank you everyone for your help. I read the schematic and realized that from all your help the pump and filter is running to the truck, NOT from an individual tank. As I was taking a video, I switched the fuel to LH from RH and the truck died. Added fuel to that tank, cranked it over and it fired up. Gauge was sweeping and was pegged maybe because of low fuel. I pulled one tank down and there is no pump in that tank so the Walbro must supply both tanks...

 

[Rumbledawg]

Ok thank you everyone for your help. I read the schematic and realized that from all your help the pump and filter is running to the truck, NOT from an individual tank. As I was taking a video, I switched the fuel to LH from RH and the truck died. Added fuel to that tank, cranked it over and it fired up. Gauge was sweeping and was pegged maybe because of low fuel. I pulled one tank down and there is no pump in that tank so the Walbro must supply both tanks...

was your gauge at the 3:00 position by chance?

 

[Rumbledawg]

Awesome!!! So its normal to have three going to the motor? I guess that frame rail pump would be either on or off. I guess what i will do is run it on LH tank, swap the selector switch and see if that pump turns off. Then ill know of the pump on the frame is running both tanks or just LH. But from the Plumbing it looks like it would do both other wise id have more lines from what your saying

the pump will run whenever the key is on and getting a signal from the ecu. if the pump relay was bad you would't be able to start your truck, and in the event of a stall or even a crash, then it would be getting a no run signal from the ecu...last thing ya want is 45 psi fuel spraying everywhere after someone hits ya..
you say you added fuel to the tank, i think i mentioned it once before, you really don't want less than a 1/4 in your tanks. your pump sucking air for even a sec or two will do it in. only real downside to using an external pump

 

[TruckCo]

Yes it was at the 3oclock. I would never run below that Rumbledog the truck was new to me and musta been empty. Do you suggest carrying an extra relay?