Do you need a relay for a fuel pump?

Do you need a relay for a fuel pump?

Well from the looks of things they don’t use a relay with it as the switch seems to be capable of directly controlling fuel pump, but unclear how much current it can handle reliably. Another potential problem is you will need to route thicker wires from your battery (which may be in the rear) to the switch and then back to the pump.

What is wiring diagram for electric fuel pump?

First some good practices, one is proper wiring, fusing and using the right safety circuits to keep you and your car safe. This project will show 2 basic wiring diagrams for electric fuel pumps. One without a warning light one with. Some parts are optional like the inertia switch, but highly recommended.

What kind of wire to use for fuel pump?

Fuel pump wiring for the RED circuit is generally going to carry a much higher current than the relay. So use a larger gauge wire for lower voltage drop. For big pumps try 12 gauge, for smaller smaller 14 gauge. You want to limit voltage drop by using a heavy gauge wire.

What kind of inertia switch does a fuel pump use?

PS118 3 Terminal 1/4″-18 NPT 2 Terminal Harness Adapters(Harder to find) Part Number 1053 Harness Pigtail AIRTEX/WELLS 1P1685 3 Terminal Harness Adapter (Should work with 2 Terminal) Wells Part Number 974 GM Original Equipment PT139 Inertia Switch Available in many styles some examples – Inertia Switch

Where does the current from the fuel pump relay come from?

This voltage comes from the ignition switch. The fuel injection computer then grounds circuit 1. This activates the fuel pump relay to pass current from circuit 4 to circuit 3. Circuit 3 is the one that runs to the fuel pump (via the Inertia Switch) and delivers the voltage/current it needs to activate.

First some good practices, one is proper wiring, fusing and using the right safety circuits to keep you and your car safe. This project will show 2 basic wiring diagrams for electric fuel pumps. One without a warning light one with. Some parts are optional like the inertia switch, but highly recommended.

How is circuit 3 connected to the fuel pump?

Circuit 3 is the one that runs to the fuel pump (via the Inertia Switch) and delivers the voltage/current it needs to activate. Before this voltage reaches the fuel pump, it has to go through the fuel pump Inertia Switch first. If the Inertia Switch has been tripped, it will ‘open’ the circuit and the voltage will not reach the fuel pump.

What is the high current circuit on a fuel pump?

The high current circuit is the one that delivers the voltage (and thus current) to the fuel pump in the gas tank (or on the frame rail). When the fuel pump relay is off (not activating the fuel pump), the high current circuit is ‘open’.