Adding second fuel tank to E450

[garlicbreath]

Hey guys,
I am trying to something a bit different.
I want an aux fuel tank, so I have some questions about the late 7.3L powerstroke fuel system.

On a 2003, is a fuel pump in the tank? (lift pump?)
Is there a return line to the tank or is it dead headed to the engine?

I don't have a bed, so I can't just use a bed transfer tank.
I want to have a large aux tank that tee's into the factory system with a solenoid right after the factory tank.

If the tank is in the back of a van, and the pickup is at the top, would I need an in tank pump or will the system pull from it ok?

[jesilvas]

No. One fuel pump, under driver seat, inside frame rail.
Yes, there is a return line at the fuel bowl, the fuel rails in the heads are dead head though.
If the pickup is at the top, I think it'd pull fine as long as you don't lose vacuum. But of course, the stock system is like that. Pulling up through the top of the tank.

[garlicbreath]

So there isn't a return to the tank?
What about getting air in the lines when switching from one tank to the other?
I might be using converted kegs that I would need to unhook and change out, sort of like propane tanks on a forklift.

What happens when you get air in the lines on these trucks? Before the pump?

[jesilvas]

Yes there is a return.
It goes like this, fuel pickup in tank, through lines to pump, on through lines to the fuel bowl. There is where is splits. Whatever fuel the injectors wind up using is sent out of the fuel bowl to the back of the passenger head and the front of the driver head fuel rails, which then deadhead within the heads. Whatever fuel is not used goes through the fuel pressure regulator on the side of the bowl and back to the fuel tank. If there's a TON of air in the lines as to where the truck won't even run, just turn the key on engine off and the fuel pump will cycle. It will stop after 10-15 seconds (never counted) then you can just cycle the pump and do the same thing again till you're confident the air is bled out. By doing this, the air and fuel goes into the fuel bowl but since the injectors aren't using anything then it goes back through the FPR and returns to the tank.

[garlicbreath]

Originally Posted by jesilvas

Yes there is a return.
It goes like this, fuel pickup in tank, through lines to pump, on through lines to the fuel bowl. There is where is splits. Whatever fuel the injectors wind up using is sent out of the fuel bowl to the back of the passenger head and the front of the driver head fuel rails, which then deadhead within the heads. Whatever fuel is not used goes through the fuel pressure regulator on the side of the bowl and back to the fuel tank. If there's a TON of air in the lines as to where the truck won't even run, just turn the key on engine off and the fuel pump will cycle. It will stop after 10-15 seconds (never counted) then you can just cycle the pump and do the same thing again till you're confident the air is bled out. By doing this, the air and fuel goes into the fuel bowl but since the injectors aren't using anything then it goes back through the FPR and returns to the tank.

Ok, So would I need 2 solenoids then? One to switch the feed and one for the return?

I read about pollock 6 port valves, what are the other 2 ports used for?

[jesilvas]

Yea you would. I've thought about this before. One for feed, one for return.
Never seen those or anything. I'm sure anything you want?
I abandoned this idea just because it's a lot of plumbing, a lot of wiring and not enough gain for me.

[JSchuricht]

The 6 port valve is basically two valves together, each with two inputs and one output.