Dual tanks; NO fuel

[Ronno6]

1984 C-10 Scottsdale 350 currently with carb..
Gonna install Fitech TBI EFI.........IF:

Truck quit running,
I switched tanks (valve works, or...it did...)
It makes noise when the switch is activated.
The fuel quit flowing........from either tank.
I can draw on the supply line and all I get is air.......switch setting....

I had backfed the supply line with gas and can't see any leaks, bur I need to correct my procedure to
tell for sure......

I do suspect that,as it it the same for both tanks, the trouble is either between the pump and the valve, or the valve itself....

Any thoughts as to where to look ??

 

[Ricko1966]

1984 C-10 Scottsdale 350 currently with carb..
Gonna install Fitech TBI EFI.........IF:

Truck quit running,
I switched tanks (valve works, or...it did...)
It makes noise when the switch is activated.
The fuel quit flowing........from either tank.
I can draw on the supply line and all I get is air.......switch setting....

I had backfed the supply line with gas and can't see any leaks, bur I need to correct my procedure to
tell for sure......

I do suspect that,as it it the same for both tanks, the trouble is either between the pump and the valve, or the valve itself....

Any thoughts as to where to look ??

Bypass the valve run hoses to one tank or the other. Is the problem gone? Run hoses to the other tank. Is the problem still gone? Replace the valve. Bypassing valve doesn't fix the problem,then the valve is not the problem.when I say run lines to tge other tank I actually mean just jumper around the valve to existing tank lines.