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Signs of a Clogged Fuel Filter

A fuel filter

In a combustion engine, the perfect air-to-fuel ratio is necessary for solid performance. When this ratio is off, the mixture in the combustion chamber becomes too lean or too rich, which can have serious consequences for your car. Therefore, the fuel supply plays a major role in keeping your engine operating efficiently. A clogged fuel filter interrupts this system, wreaking havoc on fuel quality and supply.

Learn the signs of a clogged fuel filter and what to do when you suspect there might be a problem.

Keeping Fuel From the Fire

Fuel is pulled from the tank by a fuel pump through lines that carry it to a system of metering and injection and then into the combustion chamber. The process varies depending on a vehicle’s age and model, but this system must always provide a consistent flow that fluctuates with demand and fuel that’s free of debris. Particles of rust, sediment and other contaminants build up under normal combustion processes, but if they get into the engine, they can damage sensitive components such as lines, seals, injectors and any quickly moving engine part they come into contact with. Fuel filters are primarily designed to keep particles out of the fuel, but they also affect flow. If a fuel filter becomes clogged, it can restrict fuel to the engine when it needs it the most.

Not Fueling Aroundfuel filter

A clogged fuel filter results in a lot of unpleasantries, but the engine will give you a few hints when it might need to be replaced. When the filter is clogged to the point of limiting flow, you may notice that your vehicle’s hard to start. At first, the engine might pick up fuel already sitting in the lines, but if it isn’t able to get more beyond that, it’s going to stall or potentially not run at all, depending on how severe the restriction is. Also, you might notice sluggish performance or a misfire going up a hill or when accelerating. This is because the fuel supply can’t keep up with increasing engine demands. One of the more serious indicators of a clogged fuel filter is a failing fuel pump. While there are other reasons a pump may go out, constantly processing debris from contaminated fuel will almost certainly do the trick.

Welcoming Change

To prevent poor performance, false starts and ruined components, your fuel filter should be changed once a year. Some are harder to get to than others, as manufacturers sometimes place them in the fuel tank itself. But, an inline fuel filter isn’t too difficult to replace, providing you have the right tools. Check your owner’s manual to find the filter location, and do a little research on the specific tools needed for the change.

Hopefully, you maintain your filters well enough to prevent clogging, but if that’s not the case, let these signs be the kick in the shins you need to remember how important it is.

Check out all the filters available on NAPA Online or trust one of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on clogged fuel filters, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.

Photos courtesy of Blair Lampe.


Blair Lampe View All

Blair Lampe is a New York-based professional mechanic, blogger, theater technician, and speechwriter.  In her downtime she enjoys backpacking wherever her boots will carry her, rock climbing, experimental theatre, a crisp rosé , and showering love on her 2001 Sierra truck.

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