5.0 Swap Fuel Pump Wiring Question? Please Help!

breves01

New Member
Nov 23, 2015
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I am installing a 1991 Mustang 5.0 GT motor / trans swap with wiring harness in a 1953 Ford Custom and my question is regarding an inline electric fuel pump that I would like to use the stock wiring and relay out of the Mustang for.
The four wires coming out of the fuel pump relay are the Green with yellow stripe which in a Stock Mustang goes to the ECC, a Pink w/Black Stripe that goes to the Starter relay / Battery, Red wire to Power Relay? and a Blue w/ Orange stripe to Pin 22 on the ECC as a ground? My questions is, can I run the Pink wire to the Battery, the Green wire to the ECC, the Red Wire to the Ignition Switch instead of the Power Relay (I am not sure how and where it tied into the power relay to begin with on the stock harness) and the Blue wire to a ground instead of back into the computer as I think I removed Pin 22 when I re-wired the computer for the swap and it would be a lot easier.
I am new to this, and I appreciate any help you can give!
 
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liljoe07

5 Year Member
Feb 18, 2009
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Cartersville,Ga
You can ground the blue/orange wire if you would like. The pump will just run constantly when the key is on and engine isn't running. Technically not the correct way to do it. But it will work. Keep in mind that the green wire that goes to the EEC is just a monitor of sorts. That green wire also needs to go to the fuel pump positive circuit.
 

breves01

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Nov 23, 2015
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Thank you for the information.
I have the green wire going from the fuel pump relay to the inertia switch and then to the positive terminal on the fuel pump.
If I wanted to do this the correct way, where would I go with the Red wire? Recap......(From the fuel pump relay) If I send the green to the ECC, the pink to the starter relay (By the way, does it matter what side of the starter relay terminals?), the blue to the ECC pin 22, where would the red wire go?
Where does the Red wire from the Fuel pump relay tie back into the main harness? Most places I read said that it goes to the Power Relay. Was it spliced into one of the red wires leaving the power relay heading towards the engine bay? Or, was it tied in somewhere else?
If I reconnect the Blue wire back to the computer at pin 22, will that solve my pump running constantly when the ignition is on? Or does that have to do with the red wire heading straight to the ignition.
Thanks for all the help, I really appreciate it!
 

liljoe07

5 Year Member
Feb 18, 2009
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363
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Cartersville,Ga
Red wire comes from the EEC relay. Then the computer just grounds the blue wire to activate the fuel pump. So, yes, running the blue wire to EEC pin 22 will make it work as its supposed to. You need the Pink wire on the same side of the starter solenoid as the battery positive. Otherwise the pink wire would only have voltage when you are cranking.
 
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