MAF Sensor: All you need know

Cars, trucks, and SUVs all have sensors. No matter what type of vehicle you drive, it probably has several sensors. While you may be familiar with some of them, the Mass Air Flow (MAF) sensor is one automotive sensor that often goes unnoticed. So what is the MAF sensor and how does it work?

What is an MAF Sensor?

The MAF sensor is a device that measures the amount of air entering the engine's combustion chamber. It is found on all fuel-injected vehicles. If your vehicle has a fuel-injected engine, it probably has an MAF sensor. You can usually find the MAF sensor around the engine air filter and intake manifold. It's a small electrical part that measures the amount of air entering the engine's combustion chamber.

The purpose of the MAF sensor is to ensure that the engine's combustion chamber is not getting too little or too much air. Automotive engines don't just run on gas, they also need air. The combination of air and gas is what allows automotive engines to produce combustion. The MAF sensor simply checks that your engine is getting the right amount of air. Without this information, the ECU won't be able to accurately control fuel injection, resulting in erratic engine idle or worse, engine failure.

How do MAF sensors work?

There are several types of MAF sensors, but most work the same way. The MAF sensor has two wires. One wire is connected to your vehicle's electrical system. When your vehicle is running, electricity flows through this wire, heating it at the same time. When air passes through the air filter, it passes over this energized and heated wire, cooling the wire. The MAF sensor then measures the temperature difference between the two wires to determine the amount of air entering your engine's combustion chamber.

Signs of a Bad MAF Sensor

• Check engine light on
• Increased fuel consumption
• Loss of engine power
• Loss of traction
• Unstable idle
• Engine starting difficult or impossible.

What Symptoms May Indicate a Dirty MAF Sensor?

The following symptoms may indicate an MAF sensor failure:

• Excessive fuel consumption;
• Unstable idle;
• Engine stalling when hot;
• The "check engine" light indicates that the flowmeter is no longer responding.

In most cases, if the flow meter is in trouble, it doesn't need to be replaced. All that's needed is to clean it, because the electronic lamellas that are supposed to trap the air are interfering with the flowmeter's operation and need to be cleaned.

To remove dust from the air, "sport" air filters can be greased. However, this grease will tend to lubricate the air and thus the flowmeter. As a precaution, we recommend cleaning the flowmeter annually.

How do I clean a Mass Air Flow (MAF) sensor?

Identify the air intake system  

Search online or in your vehicle's owner's manual to identify your vehicle's air intake system. Disassembling your air intake system will allow you to inspect your engine air filter. The first step is to see if it needs to be replaced. You should replace the air filter immediately if it becomes clogged. Muddy or dusty riding conditions can clog the filter sooner than expected.

Cleaning your throttle body is also a good idea now. While you're at it, it only takes a few minutes to clean this sensor, which clogs in the same way as the MAF sensor and can be cleaned with the same solvent.

Locating the MAF Sensor by Disassembling the Air Intake System

The air intake system consists of plastic or aluminum tubes. It is a simple procedure to remove and locate the MAF sensor. When the air filter is removed, the MAF sensor is located right next to the air filter. If your air filter needs to be replaced, now is the time to do it.  

Cleaning the Sensor

After removal of the air intake tube, remove the MAF sensor.  

Place the MAF sensor on a towel to catch any spilled water. Spray the inside of the chassis with 10-15 jets of sensor cleaner. It's important to protect the hot wires and plate. Be extremely careful not to touch the wires in any way. As you can see, they are very delicate.

Spray the sensor and connections. Wait a few minutes for the chemicals in the sensor to dissipate before restarting the engine.

Reinstalling the Air Intake System

Your air filter and any other components you had to remove to access the sensor can now be reinstalled. Reassemble everything as you found it.

The MAF sensor should be replaced if problems recur or persist. Expert assistance is always recommended.