87 Fuel pump electrical with TBI.
 

I am finally hooking up the final pieces of my fuel system and it is time to wire it up. I am eliminating the saddle tanks, switcher and so on.

I have a modified 72 EEC tank gravity feeding a(shutoff valve) (pre filter) Walboro 225 pump(post filter) and high pressure lines going to the throttle body regulator then a return line which runs back to the top of the sending unit to flow back into the tank. I am using the sending unit's pickup as my return with the "sock" removed. The Vent lines are copied from the 72 eec tank layout and are all 3/8 break lines going up to the 87 surge tank. All my lines are Gates Green shield rated for 225psi and today's fuels.


All I want to do right now and for the next 6 months is run the the pump off the current wiring. Later going standalone harness and inertia switch. But for now keeping the oil shutoff to get me through winter. I have the dual saddle tanks and the picture below shows the wiring going to the switching unit. I want to cut these wires and the old pump(s) power turn on a 87 relay which will have power off the starter stud feeding it to run the pump. The 87 relay will be 8" above the pump inside the cab so the firewall relay and wiring should not be stressed.

Then I need the sending unit wire which I will need to extend to run up to the 72 tank's 90 ohm sending unit to work with the 87 factory gauge.

Currently I am running on the drivers tank. Passenger tank was damaged when I bought the truck so I removed it.

What wires do I need to cut and use so I retain the oil shutoff and avoid any service engine lights?

https://preview.ibb.co/fDu0oe/027.jpg

Or do the pumps receive power from another part of the truck?

Factory wiring diagram. I do not think I have the module.
https://preview.ibb.co/grUcZK/fuel_pump_wiring.jpg

Re: 87 Fuel pump electrical with TBI.
 

I just needed a better wiring diagram.

https://preview.ibb.co/gXg0Oe/fuel_p..._correct87.jpg

Pulled the selector switch on the dash and tested Tan and White and it checks out for power. Turns on for 2 seconds key on then on when cranking then goes off shortly after cranking showing me the 4psi oil switch is working.

Then the pink wire I need for the gauge is the middle pink one terminal B.