Fuel pump question

[PorterzSupra]

I have 2 fuel tanks, one main and one cell. I also have 2 fuel pumps one intank walbro 255 and a inline MSD for the cell. The lines are going to be teed together and I was gonna put on/off valves on both sources. I was thinking maybe I dont have to because the pump when turned off should hold pressure from leaking back into the tank? Like pump A is turned off and pump B pressurizes the line pump A should hold pressure not let gas leak backwards into the its tank? I might still need the valves, does anyone know if the pump would backflow when turned off when the line gets pressurized by the second pump?

 

[PorterzSupra]

My questions are too technical for SM fokes? j/p

 

[Joel W.]

Can you blow through the fuel pumps when they are off?

I have not played with either pump, so I can't answer it for ya..

 

[cadman]

To my knowlage, yes the fuel will go back through the pump. In my mind I see no way for the fuel pump to hold back-preasure from coming in. This is deduced from 2 things. When you have dual tanks in a truck, the manual valve you turn actually blocks fuel from going into the other line. And when you disconect a fuel line, you can drain that fuel back into the line, even with an inline fuel pump in place.

I believe you will have to actually have a valve that switches from one tank to another, that actually blocks fuel from the one switched off. And you'll probably have to have sperate fuel pump power switches?

Just my input, I don't know if it is correct 100%.

 

[boost fiend]

take a look at the old ford trucks and you should find your answer.

they had 2 gas tanks and 2 fuel pumps iirc. and if you ran one tank it didnt affect the level of the second tank. im not 100% sure how they did it, but it is possiable. go hit up a locak salvage yard and peek under one.

i dont work on fords, so i dont know how they did it.

 

[Mick91MkIII]

What about return lines?

 

[IJ.]

Each pump will have a non return valve in it but they don't always seal perfectly.

I'd install solenoid valves in each fuel line efter each pump and each return line.

 

[cadman]

http://autorepair.about.com/library/a/1h/bl115h.htm

So each fuel pump does have a valve that works to not let fuel in or out. But I do think you'll still want to put a valve inline to stop any back-preasure.

I love doing research like that, I learned somethin new today.