aux tank help

[83_Shortbed]

When I bought my truck the 2nd tank (passinger side) was disconnected and I was wondering where I can find diagrams or whatever to find out how to hook it back up. when looking at it I know I'm missing some of the rubber lines as well as some lines not hooked up on either side and it looks like some of the electrical parts are disconnected.

thanks in advance for any help

 

[73k5blazer]

Do you have the switch in the cab still and it's associated wiring running underneath?

There's supposed to be a valve that all the lines hook to and the wires. The basic object is this, two sets of lines in and one set to engine. Wiring controls the valve. The differ slightly from year to year, but your year should probably just have 3 from each tank, 1 vent, 1 return and 1 feed. The vent is just teed and shouldn't be run through the valve. The feed and return lines get run through the valve.
If you still have the cab switch and all the wiring in hanging below (should be on passenger rail near where the crossover lines from the driver side tank come in), then you might just get another valve from any auto parts store and hook it up and see if it works. The lines should all be self expanitory as they are all different sizes. usally 3/8 feed, 5/16 return and 1/4 vent I think. Or big=feed med=return small=vent.


The stock valves go bad all the time. If the switch is gone and the wiring is hacked/cut out, then you might think about a replacment valve from Borg warner. The 6 port model (6 ports needed for 1 feed 1 return to engine, 1 feed 1 return from each tank), is Borg Warner FSV2A. This is the valve I use on my C10 for which I added the second tank. The valve works way better than stock, but it is unfortunatly not compatible with the stock switch or wiring. You have to run new wires and it comes with a new switch. It's basically a two position double pole on-on switch for positive engagment and only requiring power to actually switch the valve. The stock valve is default to one position, and provides contant power to keep it in the other position, if anything goes wrong, the valve defaults back to it's 'default' position, potentially leaving you without gas. Plust constant voltage down there under the truck at those terminals leads to much quicker corrosion, but that's not so much of a problem where you live. Here in the rust belt, exposed elec. terminals with voltage will corrode and disentigrate in a matter of months.

 

[83_Shortbed]

thanks for the info. i do still have the switch and I have something that sounds like that valve under the truck with the wiring in the same area. when I hit the switch it doesn't do anything other then change the fuel level to about a tank and a half or what ever you would call it full tank plus about 1/2 a tank over but the truck continues to run off the drivers side tank.

do you know of anything like a Haynes manual that shows the hose and wiring diagram for the dual setup

 

[73k5blazer]

I don't know of any routing or wiring diagrams for that specifically. My books are in storage though because we're moving, the routing might be shown, the wiring definitely is not.
It's pretty straightforward though.
If you have the valve there, it's probably just bad. Those stockers never lasted more than a few years. The replacment valve for that is like $30 at the auto parts store, it may be all you need to get it going.
The sender wires from the tank should go up to the switch, and the switch just sends power down to that valve when it needs it.

 

[RootBreaker]

i had a diagram I did with mspaint.. cheesy but good...

my drive crashed and I lost everything...

I will try and see what I can find...