How to Troubleshoot a Clogged Fuel Filter

by Gregory Crews

A clogged fuel filter will prevent fuel from getting to the engine. The best way to diagnose if the filter is clogged is to first make sure the fuel pump is working. The fuel pump sends fuel through the fuel line and into the filter. The filter pulls out any debris and sediment; however, over time, sediment can clog the filter. Replacing the filter every 30,000 miles is suggested maintenance.

Open the gas cap by twisting it counterclockwise. Place your ear near the fuel inlet nozzle. Instruct a friend to turn the key to the "Start" position, leaving it in that position for five seconds. The fuel pump will prime itself, and the sound of the pump can be heard. Verifying that the fuel pump is running will help to isolate the filter. Have your friend turn off the ignition.

Crawl under the vehicle and locate the fuel filter. Follow the fuel lines to the filter and remove the inlet line. Most filters have a quick-disconnect fitting that can be pulled off the filter easily. Place a small drain pan under the line to catch any excess fuel.

Instruct your friend to turn the key to the "Start" position. Observe if any fuel flows out of the fuel line. If there is a steady flow of fuel, then the fuel pump is adequately isolated, and troubleshooting the filter can proceed. Install the inlet line onto the filter. Push on it until it locks into place. Have your friend turn off the ignition.

Remove the outlet line and hold the drain pan under the exposed pipe. Tell your partner to turn the key to the "Start" position. Fuel will flow out of the filter if the filter is not clogged. If no fuel flows out, then this indicates a clogged filter.

Reinstall the fuel line back onto the filter. Tell your friend to turn off the ignition.

Tip

  • check Removing the fuel filter and blowing through it will also determine a faulty filter. Use caution and clean the end of the filter before placing your mouth on the pipe.

Warning

  • close Use caution when troubleshooting the filter. Gasoline is highly toxic and flammable.

Items you will need

About the Author

Gregory Crews has been in the film industry for three years and has appeared in more than 38 major motion pictures and 16 television shows. He also writes detailed automotive tutorials. His expertise in the automotive industry has given him the skills to write detailed technical instructional articles.

Photo Credits

  • photo_camera pumping gas image by Mat Hayward from Fotolia.com