You vehicle's fuel filter does exactly what it's name implies. It acts as a middle man, filtering out any impurities in the gasoline sent from your gas pump to your fuel injectors. When a vehicle's inline fuel filter is functioning properly, your engine gets a healthy injection of proper fuel without any foreign substances and your car runs smoothly.
While fuel filter problems may arise from a range of places—including an old and dirty fuel tank, clogged fuel line, cheap filter element, and dirty fuel—the symptoms that manifest on the outside may not obviously suggest any of those causes.
Here are some warning signs that a fuel filter needs to be replaced.
1. Engine Won't Start
A really dirty fuel filter may prevent your car from starting at all. Fuel pressure, especially in normally aspirated vehicles, cannot overcome the clogged fuel filter. This means that despite your fuel's pressure trying to push things forward through the engine, the gasoline itself is just too thick with contaminants that failed to be filtered out. When the engine is cranking normally but won't start, check the fuel filter.
2. Engine Idles Roughly
While stopped, your tachometer might display erratic readings for your engine speed. A normal idle RPM (revolutions per minute) of a vehicle is between 400-800 RPM. If it falls below that, again while idling, your fuel filter might need to be replaced.
3. Engine Hesitates During High-load
If you're overtaking another vehicle or driving uphill and the engine hesitates, this is a sign of a clogged filter. In situations like these where you need a sudden burst of power or acceleration, your car's lack of responsiveness can be dangerous and downright scary.
The reason this can likely be traced back to an inline fuel filter issue is because each time you step on the gas pedal, you require your engine to demand higher amounts of fuel to accelerate. When the fuel delivery system is clogged or the fuel being injected into the engine isn't as pure or potent due to poor filtration, those same moments of acceleration attempt to occur without enough fuel to actually make them happen.
4. Start-Stop Engine Problem
An engine that dies frequently while being driven could be a sign of a dirty fuel filter. Your car may start normally but with a noticeable loss of power when driven. The more often you stall like this, the smaller the amount of gas your engine is receiving, likely due to severe clogs in your filter.