anybody have a write up on wiring in a external

anybody have a write up or pic on runing postive feed from external fuel pump to fuel pump relay or taping in the efi harness..i have a 91 5.0 efi mustang motor i installed but dont know how to wire up my external pump to a relay and how to power up the ecu with out burning it up..i dont have the fuel pump relay that was in the mustang so do i need to install one

 

anybody know if i have to add a fuel pump relay to my efi swap cause i didnt take the one from my dunor car

 

you do need to use a relay.
i cant rember if the computer controls the ground side of the relay or power side. i think its the ground.


if you use that diagram you will want to have ignition power goto where it says red fuel pump wire and run the vehicle chassis ground wire to the fuel pump wire from the computer.

that is if the computer controls the ground. im pretty confident thats the way it works.

 

Lol do u know where the wire is at and what color by anychance,,

 

do not but i can help you find it. ive done this conversion before but it was about 10 years ago so i dont remember the specific details.

first find the wiring diagrams for a 91 mustang. they are all over the internet.
now find the fuel pump circuit in the diagram. that will tell you the colors of the wires and if you need it on the ground side or power side of the relay

the one thing i encountered when i did this type of swap was that there is no wire that goes to the positive side of the coil in the diagrams. i just used the stock ignition wire for the coil for the vehicle that i was doing the conversion on.