When I put my car together, I wanted an electric fuel pump, but I didn't like it that they were wired so that they always ran with the key on. I find myself sitting in the car a lot listening to the radio while the wife is shopping and I don't want the fuel pump to be running. I know that an on/off switch can be used to remedy this, but I don't want to remember to flip a switch before I turn the key...
I would like some feedback on this.... Let me know if I missed any safety issues or even if you like the idea...
Anyway... I went to radio shack and bought some capacitors, resistors, and a couple diodes. I already had relays and made a fuel pump module. When you turn the key to the on position, the fuel pump primes for a couple seconds then shuts off. Once you start cranking to start the car, the fuel pump will turn back on and stay on until you turn the key off or your car loses oil pressure. At first i had it wired a different way to run one the car started, but I liked the idea of using the oil pressure switch because it implemented a safety feature... If you lose oil pressure for any reason, the fuel pump turns off. Yes, it take a couple turns for the pressure to build up when cranking, but it's not an issue because the fuel pump primed when you turned the key on, so it's ready to start....
there are four wires to hook up:
Black = Ground
Red = +12v with key on
Violet = Goes to fuel pump +12V (the fuel pump will be grounded at all time)
Orange = Ties into the Fuel Pressure Sending Unit for the Light
Here's a pic of my finished product:
