A dirty or clogged fuel filter can starve an engine of fuel and is always a likely cause of low engine power. Most modern vehicles with fuel injection systems use filters rated to trap debris between and microns a micron is .mm in diameter a human hair is approximately microns .mm. Due to their abrasive nature, even microscopic dirt or grit that gets past a faulty or dirty fuel filter can damage your engine.
Fuel filters come in many shapes and sizes and are designed to do one thing: keep dirt, rust, scale and other impurities from entering and damaging the fuel pump, fuel injectors and engine without effecting fuel pressure. Most vehicles have two fuel filters, one in the fuel tank called a strainer and one located in the main fuel line. Filtering material is made from plastic or specially coated paper that traps foreign particles that can interrupt the fuel supply.
Under heavy or high-speed acceleration, a clogged fuel filter may cause the engine to randomly hesitate, surge or sputter. Although there may be no symptoms under normal driving conditions, a clogged fuel filter will starve the engine of the extra fuel needed during hard acceleration.
Unless completely blocked, rarely will a bad fuel filter keep your engine from starting. However, a dirty fuel filter can decrease fuel pressure causing longer than usual cranking before the engine starts.
Repeated stalling while driving, especially at low-speeds or coming to a stop could signal a dirty fuel filter. Depending on the severity of the clog, your car may start right back up without any noticeable loss of power. As the clog worsens, and fuel delivery becomes more sporadic, stalling becomes excessive.
Low fuel pressure from a partially blocked filter results in a lean fuel condition and engine misfire. This can cause poor fuel mileage, rough idling and possibly engine backfire or increased engine smog.
A clogged fuel filter prevents the correct amount of fuel from reaching the engine. Trying to compensate for low fuel pressure, fuel pump pressure increases causing the pump to overheat, become noisy and fail prematurely. A saturated fuel filter that lets dirt and grit bypass the filter can clog fuel injectors, causing them to not fully open or close. This can cause any number of rich or lean fuel mixture drivability issues.
To reduce drivability problems, maintain optimum performance, reduce tailpipe smog emissions and extend the life of your vehicle, replace the fuel, air, oil and transmission filters and fluids according to your vehicle manufacturer’s recommended service schedule, or sooner under harsh, dusty or dirty driving conditions.