Working and Testing Fuel Pump Relay

Fuel pump relay are essential components in automotive vehicles. A fuel pump relay works similarly a fuse does. It transfers power to the electric fuel pump. A fuel pump is a powerful component of the vehicles fuel supply system. It controls the amount of power that is being sent through to the fuel pump. It consists of several sprockets clipped onto the combustion chamber. Fuel pump relays are made of a plastic.

The fuel pump relay is used in vehicles to turn on the fuel pump when the vehicle is started, and powers it off when you switch off ignition system. The engine control module (ECM) uses the fuel pump relay to control when you turn the fuel pump on.

The basic purpose of a fuel pump relay is to use lower current to activate the relay and produce high current. The relay isolates the control ampere circuit from the power supply circuit.

How fuel pump relay working
Fuel Pump Relay Working starts when the key is put into the ignition and turn it on position. The relay allows current to pass through the fuel pump, which becomes active and sends the fuel that is necessary from the fuel tank to stat the vehicle initially. The fuel pump continues to work until the vehicle’s engine stop working .when the vehicle is turned on and it is running, the relay shuts down.

The fuel pump draws power from the oil pressure sending unit. When the key is turned off, the fuel pump relay is activated again.

When you turn ignition system of your car on, the pump relay creates typical noise as if’s humming. If you cannot hear the noise, it shows that the fuel relay is not working effectively.

Testing Of Fuel Pump Relay
First, unplug the fuel pump relay from the ignition system. But you should be careful while removing the relay from the ignition system – make sure to remove connections.

Inside the relay, you find two control circuits terminals and two power circuits terminals.

The diagram of the circuits connections are printed on top of the fuel pump relay. If do not find the diagram, you do it easily by identifying the the thin wires connection representing the control circuit terminal and the thick wire terminal representing the power circuit terminals.

Take an ohmmeter and connect the leads of the ohmmeter to the two circuit terminals of the power circuit terminal, if the reading is infinity resistance, you need to replace the fuel relay.

Take the fuse jumper and connect one of its ends to the battery’s positive terminal and the other to the control circuit terminal. Attach regular jumper cables to other side of the control circuit terminal and to the ground of the vehicle if the fuel relay is click it is in proper condition.

If the resistance of the power circuit terminal is in the range of 100-1000 ohms, the fuel pump relay is in correct condition.
Frequently checking of fuel pump relay improves the performance of the ignition system.