dual tank fueling idea

[speeding-g60]

so my 4x4 truck, 87 SWB Chevy, lifted on 35's, blah blah blah.

i put a Corvette TPI motor in it, and a 700r4.

it has dual tanks with a switch and a 6 port switcher valve setup, factory stuff. the passenger side pump blows the fuse whenever it switches over to that tank, almost instantly. i put Walbro Gss 242's in both tanks, new at the same time. today i dropped that tank and can find no issues with anything there. the pump works just fine in the tank out of the truck. and out of the tank as well. the switching valve is relatively new, doesnt have tons of time on it.

so i am thinking about ditching the intank pumps and running a single 044 inline externally, using the switching valve still to regulate what tank supply and return goes with. putting an -AN fitted filter in line in front of the 044 as well as the intank setups are internally filtered.

making the basket work is no big deal, just extend the pickup tube down to pull from the bottom of the sump.

i guess my only real question is if anyone sees an issue with the 044 pulling from the tanks instead of pushing? i know some pumps like the A-1000 Aeromotive, they wont pull much at all. i have run 044s internally and externally, but they have always been lower than the fuel gravity drain/fed type setups. this setup will put the pump at the bottom of the tank but it has to lift the fuel up and over the height of the tank first.

anyone see a problem with this theory???

TIA for the brainstorm.

[Marc]

044's are not designed to pull a vertical column. I'd resolve the issue of why you are blowing fuses on the passenger side. my guess is probably wiring gauge issues.

[Noisy Cricket]

If it's anything like the setup in the H1 that I am playing with, it won't work because the switching valve only switches the fuel return and which sending unit goes to the fuel gauge.

Fuel pumps (OE type anyway) have check valves, so there is no need to switch the high pressure side. The pressure just sits up against the check valve in the other pump.

[speeding-g60]

it HAS to switch pump power also as it only runs one pump at a time. each tank has its own pump. and both dont run all the time.

if it fed both pumps power all the time and did like you say, passively, then the fuse would blow all the time. it only blows if it is switched to the pass side tank.

upon further researching, maybe the switching valve is bad blowing the fuse. and since when dead it defaults to the right that it is hooked up backwards now.

shit, more to check out!

HAHA!!!!

[speeding-g60]

this is what i have, two separate power leads, one for each pump.

[Noisy Cricket]

What I was saying was, the fuel pump pressure side does not get switched, because it does not need to be switched (fluid flow wise). So if you had an external pump, you would have to put another switching valve in, or put in TWO external pumps.

IIRC, the way that system worked, the dashboard switch physically switched the pumps, and the switching valve unit switched tanks depending on if it was getting power or not.

[123quattro]

It's a wiring issue for sure on an old truck. Why not just replace it all with new good wiring, and two switches running relays for the pumps?

[speeding-g60]

i got it running again (bad ICM) and while running, with no passenger side tank or pump in, switched the tanks and it just died from no fuel. didnt blow the fuse like normal.

i "think" the switching valve mught be fooked, because i dont hear or feel it move. but the default dead position is the pass side tank. i could have it in backwards, who knows. but it didnt blow the fuse with no pump in it soooooo the next test is hang and wire the pump and basket sans tank and try it again.