Mass Air Flow Sensor

• The mass airflow sensor works by measuring the amount of air that flows into the engine and reports it to the Engine Control Unit (ECU).
• The common types of mass air flow sensors are: Moving Vane Meter, Hot Wire MAF Sensor, Cold Wire MAF Sensor.
• A mass air flow sensor usually costs $180-$284. Parts are usually sold individually. Brands offer different variants when it comes to design and packaging. Make sure to choose one that is the right fit for your vehicle type.
• A faulty mass air flow sensor decreases fuel efficiency. Have your vehicle checked if the check engine light illuminates.

In order to keep a car running at its best, it is important to make sure that the engine is in good condition. One of the key components to make this happen is the mass air flow sensor or MAF. These sensors are installed in fuel injected engines to ensure an efficient combustion process.

The car’s intake system is an integral part of the engine’s health. The MAF works by measuring the amount of air that flows into the engine and reports it to the Engine Control Unit (ECU). This sensor gets accurate information on the air’s mass, temperature, and pressure. By doing this, the ECU can control the amount of fuel injected into the engine’s combustion chambers.

It is important to monitor the amount of air flowing into the engine because it can constantly change due to external factors such as temperature and altitude. Airflow also change if you have engine enhancers such as turbochargers.

A mass air flow sensor is installed in the intake manifold between the air filter and throttle valve. The MAF can be classified into three types:

Moving Vane Meter

This type of mass air flow sensor can be found in older fuel injected engines. Moving vane meters contain a door or a flap. This door pushes open depending on the amount of air that passes through the engine. It measures air density by how much the door is opened due to the air intake and sends this information to the ECU through electric signals. The ECU, in‌ ‌turn, adjusts the fuel delivered according to this information.

Although this design is simple and uncomplicated, it has its drawbacks. Moving vane meters can limit the amount of engine power because its design can restrict airflow. It can also be difficult to install and find a place to mount this kind of sensor in a tightly-packed engine bay.

Hot Wire MAF Sensor

This newer type of mass air flow sensor is more accurate than a moving vane meter. Commonly located between the air filter and the throttle valve, it uses platinum wires to measure air density. As the platinum wire increases intemperature, so does its electric resistance. As the air flows through the engine, the wire becomes cooler which also lowers its electric resistance. The difference in resistance will determine the data sent to the ECU.

One of the advantages of using this type of mass air flow sensor is that it comes in a smaller package compared to moving vane meters.  This makes finding a place to mount it easier. The sensor does not restrict airflow because it only relies on a wire. Because it has no moving parts, it will not fail easily.

If there is a drawback in having this kind of mass air flow sensor installed, it is the fragility of the platinum wire. Dirt and oil can easily damage the wire. Platinum wires can also be damaged if handled incorrectly.

Another variant  that falls under this type is the hot-film MAF sensor. It works just like the hot wire MAF sensor but it uses sensor plates instead of wire.

Cold Wire MAF Sensors

This type of sensor works just like the hot wire variant. The only difference is that it uses a second wire that is usually cold. The data from the hot wire is compared to the data from the cold wire. This gives a more accurate result in terms of air density.

Having a faulty mass air flow sensor will decrease fuel efficiency. If the MAF is not working properly, it might send the wrong signal to the ECU, causing excessive fuel consumption. Your car will also burn more fuel even when idling. If you notice that you’re filling up your fuel tank more often than usual, it might be time to have your engine checked.

Fortunately, most cars have a check engine light that illuminates when something is wrong with your sensor and engine. It is best to have your vehicle checked as soon as the warning signal appears to avoid other issues with your car.

It’s important to consider your engine’s structure in choosing a MAF sensor. This will determine the right type of MAF sensor for your vehicle. It’s best to consult your trusted mechanic and have him recommend one for you.

A mass air flow sensor usually costs $180 to $284 and are sold individually. Brands offer different variants when it comes to design and packaging. Make sure to choose one that is the right fit for your vehicle.

A mass airflow sensor or MAF was designed to measure the amount of combustible air getting to the engine. It's responsible for making your vehicle's engine run smoothly. It can be damaged or contaminated by an improperly installed air filter. This will lead to problems like: engine stalling, poor acceleration, misfiring, lack of power, and the "Check Engine" light turns on. When these symptoms arise, it's time to change the mass airflow sensor.

In this guide, we have prepared the tips, steps and tools needed to finish the project.

Difficulty Level: Moderate

Tools that You'll Need:

• Flat-head screwdriver
• Phillips-head screwdriver
• Torx-head screwdriver set (optional)
• New Mass Airflow Sensor (MAF)

Safety Tips

• Make sure that you're working on a solid, level surface.
• Always wear recommended safety equipment like closed-toe shoes, an industrial-grade dusk mask, safety goggles and gloves.
• Check your replacement parts and make sure that they are compatible to your vehicle's make and model.
• Be careful with the mass airflow sensor replacement part. Do not touch the sensor's interior elements to avoid any contamination.
• The mass airflow sensor's size depends on the vehicle's make and model. Consult your owner's manual or dealership for the correct type and make.

Step 1: Open your vehicle's hood and make sure it's secure.

Step 2: Locate the engine's air box to remove the air filter. Some air boxes have metal clips to secure it. Use your fingers to remove the clips to open the air box.

Step 3: The mass airflow sensor is usually located near the air filter housing or the intake tube.

Step 4: Remove the tube by using a Phillips screwdriver to unbolt the mounting hose clamps or rings.

Step 5: Unplug all the electrical connections from the sensor. Make sure to take note of their positions so you won't have problems reconnecting them.

Step 6: Remove all the mounting bolts securing the sensor to the body plate.

Step 7: Loosen and remove all mounting screws from the sensor's case. Remove all the tubes connected to it.

Step 8: Remove the old sensor from the case and make sure that all electrical wirings have been unplugged.

Step 9: Install the new mass airflow sensor and reassemble all the tubes connected to it. Make sure that the air tube is reconnected to the air box cover.

Step 10: Insert the air filter into the air box and secure the cover with the metal clips.

Step 11: Check if all the mounting clamps and bolts are secured. Plug the harness back into the sensor unit.

Step 12: Start your engine and check if the mass airflow sensor is working properly.

Installing a new mass airflow sensor will take about an hour for an expert DIYer and around an hour, 30 minutes for a beginner.