Understanding, Functions, and How MAF Sensors Work in Cars
31 January, 2024
Combustion occurs in the combustion chamber of a car engine and can occur properly if there is proper air and fuel intake. Mass Air Flow, abbreviated as MAF, is one of the components in cars with an EFI, or Electronic Fuel Injection System, specifically types L (L-EFI) and D (D-EFI).
This sensor plays a significant role in supporting the machine’s work. If this sensor has a problem, the engine will work improperly, which can result in damage and discomfort to the car when used.
In order to find out the problems that can occur due to the MAF sensor, see the review below regarding the MAF sensor in cars, starting from its meaning, function, and how it works.
Understanding MAF Sensor
Mass Air Flow (MAF) is a sensor located in the air filter that goes to the throttle body or intake manifold. Its function is to detect the amount of air mass flowing into the combustion chamber intake.
This air flow sensor has a part called a “hot wire”, which consists of a wire or cable that is heated by an electric current. The function of the “hot wire” is to send a signal to the ECU indicating the amount of air entering the intake.
What is the Function of the MAF Sensor for Cars?
One of the main functions of the MAF sensor is to measure the amount of air entering the combustion chamber. Apart from that, most MAF sensors also have an IAT (Intake Air Temperature) sensor, which detects the temperature of the air entering the intake manifold.
Changes in the amount of air entering the combustion chamber through the intake manifold are adjusted to the size of the throttle valve opening. With a large amount of incoming air flow, this sensor will issue a changing signal to the ECU, and then the ECU changes the sensor signal using changes in resistance produced by the large amount of incoming air flow.
How the MAF Sensor Works
The MAF sensor consists of two wires: a hot wire and a thermistor, which is a wire with different resistance to the temperature it hits. This is a hot wire that is heated by an electric current and is used to detect the intake air temperature on the IAT sensor.
The way it works is that when the ignition is turned on, electric current from the battery flows to the hot wire, which heats up due to the buildup of electrons. The temperature of the wire also increases by around 3 volts. When the engine is started, air flows from the filter to the intake. Because the high temperature of the hot wire will be released by the air flow when the air flow passes through the hot wire, the temperature of the hot wire will drop.
Hot wire has constant properties; when the temperature drops, the electric current also increases. At idle speed, the current flowing is greater than 3 volts initially and can reach 5 volts at idle.
The faster the air flow, the more air mass will enter the machine and the more electric current is required by the hot wire. The electric current released from the hot wire is what the ECU uses to calculate how much air mass enters the engine.
Symptoms of MAF Sensor Damage
This component is susceptible to dirt because its performance is supplied with air from outside. If the MAF sensor is exposed to dirt, its function will be disrupted and have an impact on the car’s performance. Here are some symptoms of MAF sensor damage:
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Rough Machine
The engine will vibrate with a louder or rougher sound if the air-fuel mixture is not suitable. If the throttle body and air filter are dirty, the same symptoms will also appear.
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The Engine is Difficult to Start
When the air intake is insufficient or excessive, the engine will work harder. This is because the air-fuel mixture does not match the engine’s needs. However, this symptom can sometimes be resolved by removing the MAF sensor socket.
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Air and Fuel Mixture Not Ideal
When the MAF sensor is dirty, the air and fuel intake readings will be wrong, so the ratio does not match the engine. Too much air or even too little air can cause inefficient fuel delivery.
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The Machine is Difficult to Idle
When the MAF sensor’s air readings are dirty, the information provided to the ECU becomes inconsistent, causing engine rpm to rise and fall, even when the engine is idling.
Criteria for a Good MAF Sensor
The MAF sensor is very important for injection cars, so it must be checked carefully before installation. The MAF sensor is considered usable if it meets the following requirements:
- The MAF sensor can work accurately. If it is inaccurate, the combustion system will be disrupted.
- Can work according to changes in air flow entering the combustion chamber quickly.
- The process of transmitting and receiving signals is good.
Knowing the importance of the MAF sensor, from here you can find out the function and symptoms of damage that could occur in your car. So if symptoms occur that indicate the sensor is damaged, it can be resolved immediately by taking it to a trusted repair shop to replace the sensor.
