Electric fuel pumps & electric tank switch & gauge switch - ALL TOGETHER?

[joshd1971bronco]

I am planning on running an electric fuel pump(s) for my carb'd motor. I have dual tanks on my bronco - one 23 gallon main and the factory auxilliary side one.

1) I assume I need TWO pumps for the two tanks since you should get the pumps closest to the tank they're drawing from - CORRECT? Or does this whole thing get simpler and I run one pump downstream of both tanks?

2) Assuming I need two pumps, can I wire the switch that controls the gauge on the dash to run the electric fuel tank switch (that I'll buy to replace the manual one) AND the pumps themselves? What I'm thinking is that by throwing the one switch on the dash I will
a) switch the gauge on the dash to read from the selected tank
b) switch the electric fuel tank switch to pull gas from the same tank
c) switch on the pump from the same tank

I hope that makes sense - is that doable? I'm pretty confident I can figure out how to wire it - don't need much help with that I don't think - I just want to make sure the theory isn't flawed.

Thanks.

 

[Broncobowsher]

Before converting to EFI, I ran dual tanks with an electric pump, pulling fuel all the way to the engine compartment just like the factory did with the mechanical pump. Let the pump suck straight from the selector valve. Just the good Carter P4070 pump. Never had an issue with it. Running a Bronco as a daily driver in Phoenix in the summer and it was fine.

There are a few pumps that don't take a prime well (centrifical come to mind). And if you run a fuel line past something hot and create a vapor lock condition then the pump will hate pulling fuel. But the same pump would be fine pushing fuel past the hot spot due to the pressure/vapor curve where it is much harder to boil pressureized fuel and easier to boil non-pressureized fuel.

There is some truth to the pumps work better pushing then pulling. Most of which is to cover other problems. If the fuel system works with the mechanical pump, and you have a good electrical pump, it can just take the place and does not need relocation.

 

[blubuckaroo]

If you change over to an electric selector valve, you can mount the pump and valve on the frame behind the aux tank. This is a really good spot because it is where the fuel lines come out of both tanks. You will have the shortest suction lines possible.

 

[Steve83]

You don't need a selector valve. Common, inexpensive solenoid-style fuel pumps have check valves built in, so you can just Y them into the fuel filter & run that to the carb. Fuel from the active pump will be automatically blocked from going backward thru the inactive one. So it'll be easier & better to have a pump near each tank.

And a stock '87-96 F-series fuel tank switch will control both the pumps & the gauge exactly the way you want. The '87-91 switch is slightly easier to mount than the '92-96.

 

[broncnaz]

One pump is all thats needed. I've used the carter P4070 as well for over 30 years without issue on dual tanks. Mines mounted on the frame above the rear axle. Yes you can use the stock gauge selector switch on the dash to operate both the guages and a electric tank selector. The stock switch has unused terminals that can be used to wire up a electric selector switch.

 

[joshd1971bronco]

That's awesome. I appreciate the responses from everyone. Gave me some good ideas and I know how to appraoch it now. I've ordered two identical electric fuel pumps (one for a trail spare) and will be wiring it like most here said.

Thanks again.