How To Wire A Relay For Fuel Pump

Wire from the fuel pump to an under hood relay.

How to wire a relay for fuel pump. Fuel pump wiring for the red circuit is generally going to carry a much higher current than the relay. The diagram is color coded per circuit and only a few things may need to be said. Wiring in the fuel pump relay. So now instead of the stock ecu energizing the fuel pump it will energize this relay.

The other side of your fuse device goes directly to the battery terminal. Join one more wire to the 85 terminal of the relay which acts as the ground wire. Wire the oil pressure switch s s terminal to the ignition cranking start circuit to provide fuel pump pressure during engine cranking and or via a dash mounted toggle switch to prime empty. So use a larger gauge wire for lower voltage drop.

The 86 position goes to a 16 ga. This wire will connect to the 87 terminal position. How to connect a fuel pump relay get the book at amazon. Listen for the fuel pump to activate.

The 30 position on the relay will go to a fusible link in line fuse or circuit breaker. Basic safe electric fuel pump wiring diagram this is the basic wiring diagram for safe electric fuel pump wiring. If you are using a fuel injection system then you need to use the fuel pump signal as the trigger for the relay. You may have to have an additional person touch the fuel pump relay to feel the buzz or clicking motion.

The fuel pump relay may be faulty or have a loose connection if it s developed any rust or corrosion on the prongs. Turn off the ignition after the fuel pump stops making noise. Turn the key on again and listen for the fuel pump relay to buzz or click. Scrape off as much corrosion as you re able to so the relay has a solid connection when you plug it back in.

Wire pin 85 of the relay to the 12v supply wire from the stock ecu that you just cut. They are usually labeled 30 85 86 and 87. Electric fuel pump relay wiring diagram electric fuel pump relay wiring collection wiring diagram rh visithoustontexas org electric fuel pump parts holley electric fuel pump diagram. For carbureted engines you can connect the relay to a switched ignition source must have power in both start and run key positions or you can simply wire in a manual switch.

Hold the relay upside down so the prongs point up and firmly scrape them with a wire brush. The relay should have 4 pins on it. You need to run at least a 10 ga.