i have an 89 gt, 5.0 . i blew th e motor and got my buddys race motor. its got a carb and is set up with a return line. he said there is wire to ground out to make the fuel pump run when key is on at all times. anybody heard of this?
The only way that works is with EFI cars. The computer controls the fuel pump relay. See http://www.veryuseful.com/mustang/tech/engine/images/88-91eecPinout.gif for the location of the tan/Lt green wire (fuel pump relay control circuit). On EFI cars, ground this wire & the pump runs whenever the switch is on