Your Trusted Auto Repair Shop for 40+ Years
Shop Talk Logo

What Happens If You Don’t Replace a Fuel Filter?

what if you dont replace fuel filterFilters, though often forgotten, are the mighty protectors of all things. Without filters you’d have coffee grounds floating in your latte, you’d be swimming in a green pool, breathing contaminants that enter your home and car through the air, drinking all kinds of questionable particulates, and…well, you get the point. Filters literally trap things that could be detrimental to your body, home, car, and more. Your car is equipped with several filters to help trap pollutants and other foreign objects from entering major components and causing severe damage. The fuel filter, in particular, plays a key role in delivering clean fuel to the engine for combustion. A clogged or damaged fuel filter is bad news. 

The fuel filter is tasked with ensuring pure, clean fuel is delivered to the fuel injectors and to prevent any contaminants from entering the engine. Though these protectors are tough and aid in preventing major catastrophe, they are made only of pleated, porous materials that can become clogged over time due to sediments that have settled into the gas tank or if poor quality fuel is used. Particles and other debris reduce the amount of fuel that is able to flow through the filter. Once entirely blocked, you won’t get very far. In fact, you won’t even be able to start your car. 

What Happens If You Don’t Replace the Fuel Filter

All combustion engines require a certain amount of fuel to start and run. The fuel filter is put into action every time the vehicle is started. If there are problems within the fuel system, such as a blocked fuel filter, the vehicle may experience:

  • Misfiring – Misfiring occurs when the engine misses one of the steps in the combustion process. Misfiring causes the engine to run rough, jerk, or buck. A blocked fuel filter is just one example of what causes engine misfire. 
  • Idling problems – Idling trouble can occur due to obstructions in the fuel filter preventing the engine from receiving enough fuel. Rough idle caused by a clogged fuel filter is the result of the engine being starved for fuel, preventing the engine from receiving the proper amount of fuel and air in the combustion process.
  • Stalling – A vehicle with a dirty or blocked fuel filter is one of the main reasons in what causes an engine to stall while driving. A blocked fuel filter prevents fuel from traveling through the fuel lines to the engine, starving your engine of fuel. If your engine is not getting fuel, it simply will not run.  
  • Difficulty starting – Vehicles that are hesitant to start may have a moderately clogged filter and if not replaced soon, the vehicle will fail to start at all. Fuel pressure in fuel injected engines is hindered when the fuel filter is blocked. 
  • Check engine light on – Vehicles equipped with fuel pressure sensors to monitor the amount of pressure in the fuel system can recognize when fuel pressure drops, for any reason, including a clogged fuel filter. 
  • Sputtering while accelerating – Lack of power from the engine, especially during acceleration, can be the result of a dirty fuel filter. The engine’s computer restricts the output to protect the engine from potentially damaging contaminants. The vehicle will produce a sluggish feeling and may even trigger the Check Engine light. 

How Often Should a Fuel Filter Be Changed?

In the past, vehicle manufacturers recommended changing a fuel filter every 30,000 miles. However, with the vast improvements made to modern vehicles, a fuel pressure test is the best way to determine whether you should change your fuel filter. A fuel pressure test is able to measure the output of PSI from the fuel pump at the fuel lines that transport fuel to the injectors. The fuel pressure should register over 30. If the number reads lower that, you should have your fuel filter replaced

The fuel system is a critical component when it comes to getting your vehicle moving. When your engine doesn’t receive the fuel it needs, it may behave unusually or fail to start. The fuel filter is one of the most important components in the fuel system. It prevents contaminants from entering the fuel lines and damaging vulnerable components within the engine. Modern vehicles have greatly improved the fuel delivery process, but with these improvements, replacing the fuel filter has become a bit more challenging. Now located within the fuel tank, a qualified and Certified Technician should be called upon to replace the fuel filter or perform any repairs on the fuel system.