Dual Walbro Wiring Install
06-26-2015, 11:06 PM
#81
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Location: Kansas City MO
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So I've just modified my existing fuel pump housing and installed 2 Walbro 255's. Can I just wire to the existing fuel pump wires or do I need to install the relays also?? Thanks.
11-07-2015, 06:21 PM
#82
I wanted to show people exactly how the wiring should be set up when installing dual fuel pumps with relays. I am using a Hobbs switch to kick the second pump on when I get into boost.
I bought a dual relay with wires setup from summit. Its a VPA #80238. I like this setup because it has both relays attached together and a plug that connect them both with wires coming out of it. These relays are 30 AMP SPDT relays.
Here is the diagram on my relays in case you have a different relay you can decypher it
On these relays here are the numbers on the relay and the color wire for each number
87 red
87a yellow
85 black
86 white
30 blue
Now here is how you will wire it up.
------------------------------
Left Relay (Primary pump relay)
Black - Ground
White - PCM
Red - Battery
Blue - Pump
------------------------------
Right Relay (Secondary pump relay)
Black - Hobbs Switch
White - PCM
Red - Battery
Blue - Pump
You wont use the yellow wire for anything, you can snip it if you like
Here is a picture of the stock wiring harness that connects to the fuel pump
Use the tan wire for the signal wire to energize the relay for your main pump,The black wire was the ground. The other 2 wires are for the fuel level sending unit.
Primary pump wiring--
You will use the tan power wire(From the factory harness) for the signal wire(PCM) and ground your black wire. You will then hook the red wire to your battery power and run the blue wire to your pump. Take your ground wire from your pump and connect it to a good ground somewhere outside the tank.
Secondary pump wiring--
You will use the tan power wire(From the factory harness) for the signal wire(PCM) and connect your black wire to the hobbs switch(This completes the connection to ground when you get into boost). You will then hook the your red wire to your battery power and run the blue wire to your pump. Take your ground wire from your pump and connect it to a good ground somewhere outside the tank.
I would run 10 gauge wire from the battery to your relays, and connect both of your power wires from the relays into your 10 gauge battery power.
I bought a dual relay with wires setup from summit. Its a VPA #80238. I like this setup because it has both relays attached together and a plug that connect them both with wires coming out of it. These relays are 30 AMP SPDT relays.
Here is the diagram on my relays in case you have a different relay you can decypher it
On these relays here are the numbers on the relay and the color wire for each number
87 red
87a yellow
85 black
86 white
30 blue
Now here is how you will wire it up.
------------------------------
Left Relay (Primary pump relay)
Black - Ground
White - PCM
Red - Battery
Blue - Pump
------------------------------
Right Relay (Secondary pump relay)
Black - Hobbs Switch
White - PCM
Red - Battery
Blue - Pump
You wont use the yellow wire for anything, you can snip it if you like
Here is a picture of the stock wiring harness that connects to the fuel pump
Use the tan wire for the signal wire to energize the relay for your main pump,The black wire was the ground. The other 2 wires are for the fuel level sending unit.
Primary pump wiring--
You will use the tan power wire(From the factory harness) for the signal wire(PCM) and ground your black wire. You will then hook the red wire to your battery power and run the blue wire to your pump. Take your ground wire from your pump and connect it to a good ground somewhere outside the tank.
Secondary pump wiring--
You will use the tan power wire(From the factory harness) for the signal wire(PCM) and connect your black wire to the hobbs switch(This completes the connection to ground when you get into boost). You will then hook the your red wire to your battery power and run the blue wire to your pump. Take your ground wire from your pump and connect it to a good ground somewhere outside the tank.
I would run 10 gauge wire from the battery to your relays, and connect both of your power wires from the relays into your 10 gauge battery power.
08-27-2017, 11:32 AM
#84
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Join Date: Apr 2012
Location: Hendersonville TN
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I had the same issue discussed above about the pumps running all the time. Turns out my relays came wired differently that the OP. Colors were off. The center was red....not yellow. If this happens to you, just make sure the center wire (87a) is not being used.
