Dual Tanks Fuel switch delete

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1974Blueflame

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I have a fuel switch issue and don’t really want to have to switch between tanks has anyone just configured the hoses into a T going to the fuel pump?
 
WFO

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1974Blueflame said:
I have a fuel switch issue and don’t really want to have to switch between tanks has anyone just configured the hoses into a T going to the fuel pump?
Click to expand...
I did on a 1980 company truck, while doing a job out of town. Worked fine for the couple of months it took to finish the job, then fixed it when we got back home.
The tanks will equal out, and the gauge was the most accurate after it had been parked for a while.
 
Grit dog

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1974Blueflame said:
I have a fuel switch issue and don’t really want to have to switch between tanks has anyone just configured the hoses into a T going to the fuel pump?
Click to expand...
No return line(s) that will work. 3 port sender and return line fuel pump, that will not work.
 
WFO

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Grit dog said:
No return line(s) that will work. 3 port sender and return line fuel pump, that will not work.
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Worked for me. I don't make this stuff up.
Didn't even mess with the return line. I reckon it only returned to the one tank that had been previously switched to, but the tanks equalized themselves anyway.
 
bucket

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WFO said:
Worked for me. I don't make this stuff up.
Didn't even mess with the return line. I reckon it only returned to the one tank that had been previously switched to, but the tanks equalized themselves anyway.
Click to expand...

So you are saying that with the supply lines tee'd together, the tanks balanced due to a siphon effect through the supply line? Makes sense.

I'm sure there's going to be a scenario where that setup could possibly cause an issue though, if someone did it that way permanently.
 
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Ricko1966

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bucket said:
So you are saying that with the supply lines tee'd together, the tanks balanced due to a siphon effect through the supply line? Makes sense.

I'm sure there's going to be a scenario where that setup could possibly cause an issue though, if someone did it that way permanently.
Click to expand...
It's going to cause an issue eventually if/ when 1 tank runs low enough to lose prime and siphon effect. NBD I just don't want to be the guy adding fuel to the low tank at the side of the road.
 
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Ricko1966 said:
It's going to cause an issue eventually if/ when 1 tank runs low enough to lose prime and siphon effect. NBD I just don't want to be the guy adding fuel to the low tank at the side of the road.
Click to expand...
^^^ This

If the system would work well without a selector valve GM wouldn’t have spent the money putting them in.

If you need to hack it to get by for a while, then so be it.

Whichever tank has less resistance to pull the fuel from may end up getting ran dry faster than the other. When my selector valve went bad it pulled from both tanks, too many times one tank would run dry and would not even be able to start unless I primed the carburetor even after adding gas to the empty tank.

You’re better off replacing or repairing the selector valve (common failure), switch, or wiring.
 
Grit dog

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CalSgt said:
^^^ This

If the system would work well without a selector valve GM wouldn’t have spent the money putting them in.

If you need to hack it to get by for a while, then so be it.

Whichever tank has less resistance to pull the fuel from may end up getting ran dry faster than the other. When my selector valve went bad it pulled from both tanks, too many times one tank would run dry and would not even be able to start unless I primed the carburetor even after adding gas to the empty tank.

You’re better off replacing or repairing the selector valve (common failure), switch, or wiring.
Click to expand...
Good point. I assumed they’d pull somewhat the same until maybe low fuel level.
Which brings out the other workaround of connecting both tanks on the bottom to equalize. That definitively works. Just difficult to execute as a safe and long term solution.
 
fast 99

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Grit dog said:
Which brings out the other workaround of connecting both tanks on the bottom to equalize.
Click to expand...
Done on larger [higher] over the road trucks.

Our company used low profile trucks. Factory would not install dual tanks like that because the possibility of damage and fuel spill.
 
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bucket said:
So you are saying that with the supply lines tee'd together, the tanks balanced due to a siphon effect through the supply line? Makes sense.

I'm sure there's going to be a scenario where that setup could possibly cause an issue though, if someone did it that way permanently.
Click to expand...
Exactly

Like I said it was a temporary fix while we were working out of town staying at a Motel, and couldn't be without a truck.
I made sure that the fuel levels never got low.
 
Tyger13us

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9 times out of 10, its been the switch on ALL my twin tank trucks, i take a working switch out of one of my trucks and plug it in the none working one and it works again.
Ive never had a bad selector valve, some times the plug gets full of crap? or the gauge in the tank goes bad..
Just my personal exp.
 
85 red GMC

85 red GMC

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Ricko1966 said:
It's going to cause an issue eventually if/ when 1 tank runs low enough to lose prime and siphon effect. NBD I just don't want to be the guy adding fuel to the low tank at the side of the road.
Click to expand...
Since you have a switch and they (at least mine) do not tend to stall in the switching process with engine running, what is the benefit of eliminating the switch. Looks like of lazy to me.
 
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Ricko1966

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85 red GMC said:
Since you have a switch and they (at least mine) do not tend to stall in the switching process with engine running, what is the benefit of eliminating the switch. Looks like of lazy to me.
Click to expand...
I don't want to eliminate anything. I was telling the O.P. the downside of not fixing it right.
 
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