Installing 2nd tank

[kychevy]

Going through this Frankenstein truck and realized it came with dual tanks. A previous owner has, somehow, rewired it so the RH tank works. The switch on dash is gone, the valve on the passenger side frame has been removed and wires have been hacked up. I have the switch and selector valve on order but I’m trying to trace down the wiring so I can get rid of this half assery. In the diagram below I am wanting to find the “splice” where the fuel pumps tie into the selector valve and switch wires(yellow circle) so I can get signal to the valve. They have used a pink and tan/white at the firewall to send signal to the tank but it looks like those wires shouldn’t even go back there. Idek if I should keep going this route or just bring out the cc and pay for a new harness or maybe I need to go look at another 87 squarebody to see what I’m missing. ‍

 

[kychevy]

Pink and tan/white wire

 

[SirRobyn0]

My truck was a single driver side tank only fro the factory. After I bought the truck I installed a second tank on the passenger side because the range was to poor for when I did my feed hauls for the farm and ran 100 miles to get loaded and 100 miles back loaded.

So my truck is carbureted. Yours is TBI, I can't really help to much with first hand knowledge of what wire goes where. I could direct you to wiring diagrams but it looks like you already have them. So my one suggestion is, if the switch is gone and you have a mess for wiring consider installing this.

Pollak PN# 42-308P It's a fuel tank switch kit, designed to be used on a carbureted fuel system or injected I think it can handle up to 60PSI IIRC. I think Standard motor products sells a version of that too. Anyway it's a 6 line valve so it can handle return lines if you have them, it'll switch the gauge and using the same wire as the gauge switching uses you can set up a relay to energize the pumps.

It's pretty much our go kit when we need the switching system.

 

[kychevy]

Appreciate that info. May go that route. I have determined what all the wires are at the gas tank and seems like they are all there….just the ends have been cut off. So my attention has turned to the gray and tan/white wire coming from the switch in the cab. It appears to come through firewall and goes over to RH side of engine to a big splice, from there idk. Kindof losing it after that point but I do know one of those wires go to a black connection mounted on the intake. What is that thing?

 

[SirRobyn0]

Appreciate that info. May go that route. I have determined what all the wires are at the gas tank and seems like they are all there….just the ends have been cut off. So my attention has turned to the gray and tan/white wire coming from the switch in the cab. It appears to come through firewall and goes over to RH side of engine to a big splice, from there idk. Kindof losing it after that point but I do know one of those wires go to a black connection mounted on the intake. What is that thing?

If you get that pollak kit I was mentioning it would come with a pigtail, so you could potentially install the new valve, and the pigtail and not use the other parts of the kit. The kit comes with a wiring diagram that you can match up to your truck.