How to Check Your Fuel Pump Voltage in 7 Steps

If your fuel pump has insufficient pressure and flow, don’t be so quick to throw it out. It doesn’t always mean that the pump is failing. It could just be underperforming due to low voltage, a bad connection, or a bad ground connection.

 

You can find out if your pump is failing or underperforming by checking its voltage.

What You’ll Need

  • 2 jumper wires
  • A digital multimeter
  • Safety glasses
  • A couple of hours
Multimeter

A digital mutlimeter, via Andre Karwath

Always follow the auto manufacturer’s recommended procedure for testing the electrical system in your vehicle. We’ll delineate the general steps below but you’ll have to refer to your owner’s manual for instructions on performing certain tests.

Step 1: Make Sure There are No Damaged Circuits Anywhere Between the Fuel Pump and Relay

A damaged circuit will render your test useless. If you find one, fix or replace it before performing any of the voltage tests.

Step 2: Test the Relay

The relay has to work properly for you to get accurate voltage test results.

Step 3: Connect the Digital Multimeter to the Fuel Pump

Ensure that your vehicle is off. Connect the digital multimeter to the pump’s positive and negative terminals.

Step 4: Turn the Car on Without Starting the Engine

This is to activate the fuel pump. You should hear a soft whirring noise coming from the pump.

Step 5: Check the Digital Multimeter’s Reading

It will indicate whether your fuel pump is receiving enough electrical power. Sometimes your multimeter will give you a false voltage reading if there’s a deficiency in the power supply. To double check, continue the next steps to perform a voltage drop test.

Step 6: Split a Live Circuit Into Two and Test the Negative and Positive Terminals

Do the tests with a live circuit wire to get an accurate voltage drop reading. If it’s greater than 0.1, that means your pump is receiving inadequate voltage power. It could be attributed to damaged harness connectors or faulty wiring.

Step 7: Test the Pump for Voltage

To get accurate results, remove the fuel pump from your vehicle and lay it on a flat surface before performing the test.

If the test results show that your fuel pump is indeed failing, you can get replacement OEM quality fuel pump components from Auteria at wholesale prices.