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Making Sense of Your MAF Sensor

Mass air flow sensor isolated on white background. Auto service industry. Spare parts catalog Auto service industry. Spare parts catalog.

Your engine runs on a combination of fuel and air. When you press the accelerator, the pressure you apply to the pedal requests how much of each you need to accelerate, go up a hill, or handle other driving conditions. Based on how much air you need (and how much is available) your engine’s computer will send the necessary amount of fuel to the engine.

If the computer has the wrong information, however, it will send an incorrect amount of fuel, causing your engine to perform poorly and run less efficiently. How does the engine’s computer know how much fuel to send? A small but essential component called the Mass Air Flow Sensor (MAF).

How Does the Mass Air Flow Sensor Work?

The MAF sensor measures several important factors: the volume, temperature, and density of the air coming into your engine. Using that information, the computer calculates how much oxygen is available to burn, as well as how much fuel it should send to the engine. If the MAF sensor becomes dirty or damaged, it will provide inaccurate airflow readings, which can lead to drivability issues or damage to the catalytic converter. It can also cause the Check Engine light to come on, which may prevent the engine from running.

The good news? There’s a very simple way to prevent some dirt, dust, pollen, and other contaminants from reaching the MAF sensor: changing the engine air filter. When the air filter becomes dirty and clogged it allows some of the contaminants to pass through and reach the MAF sensor, where they can start to accumulate.

Common Signs of a Dirty MAF Sensor

Some common signs of a dirty MAF sensor include:

  • Stalling, jerking, or hesitation while accelerating
  • The airflow is too rich, which can cause black smoke from the tailpipe, poor fuel efficiency, rough idling, or the check engine light to display
  • The airflow is too lean, which can cause engine hesitation or surging, hard starts, engine seizures, or the check engine light to display

What Can I do if My MAF Sensor is Dirty?

If your MAF sensor is dirty, we may be able to clean it using a method called air induction. This service also cleans other components in the fuel system, like the throttle body. If the MAF sensor is damaged, though, it will need to be replaced.

The easiest and best way to help your MAF stay clean and accurate (and help your engine run smoothly) is to make a point to change your engine air filter according to your manufacturer’s recommendations. Approximately 12,000 gallons of air pass through your engine air filter for every gallon of fuel you burn. That’s a lot of air to clean, so it’s important to make sure your air filter is up to the task!

Replacing this relatively inexpensive part will not only prevent dirt and debris from entering your engine, but will also preserve the life of your MAF sensor and keep it working properly. It’s also important to note that the fiber in low-quality air filters can come loose and contaminate the sensor, too. For this reason, it’s a good idea to invest a little more and get a high-quality air filter.

Keep Your Engine Performing its Best

A good air filter is an engine’s first line of defense against contaminants, so it truly pays to keep up with filter changes as part of your routine maintenance. If it’s been a while since you last had your air filter changed, have one of our technicians check it at your next appointment. Some signs of a clogged air filter are issues like engine misfires, rough idling, or hard starts.

As your local European auto experts, EuroCar Service helps you keep your engine performing its best! We see all European makes, including Audi, BMW, Mercedes, Land Rover, Jaguar, Mini-Cooper, Saab, Volvo, Smart Car, Fiat, and Volkswagen. Schedule an appointment today at (206) 527-8828 or request an appointment online.