Mass Air Flow Sensor: Accurate Intake Air, Correct Fuel Injection

1. Working Principle

There are a heater and a temperature sensor between the air filter and the throttle body. The air flowing through the heater will take away heat and make the heater cooler. The more air flows through the heater, the more heat is removed.

The temperature sensor detects the temperature change and sends the data to the engine control unit. The ECU then calculates the airflow according to the temperature change.

The air flows through the mass air flow sensor when the vehicle is running. It pushes the turbine blades to rotate. The number of impeller revolutions is proportional to the volume of gas passing through the air meter. A specially designed deflector is installed at the meter's inlet to accelerate the airflow into the sensor as the flow rate increases.

The deflector eliminates all potential fluid disturbances such as vortex or asymmetric flow. The pushing force on the turbine blades is increased at the same time. This ensures that the flow meter measures with high accuracy within the permissible error range, even in small flow conditions.

2. Function

The mass air flow sensor is mounted on the intake hose between the throttle valve and the air filter. Modern engines have air flow meters providing intake pressure and air temperature signals.

The air flow meter, water temperature sensor, throttle position sensor and oxygen sensor work together to provide the ECU with reference fuel injection signals. The ECU calculates the best injection volume according to these signals. The mass air flow sensor plays a big role.

3. Symptoms

The mass air flow sensor is critical to fuel injection and engine running. So what failure performance may annoy you if this sensor is damaged?

●  Abnormal signals

When the mass air flow sensor is faulty, it is often accompanied by a wrong indication of the fuel injection amount, which directly leads to the situation that the fuel injection amount does not match the actual working condition.

As time goes by, it causes carbon deposits in the engine cylinder. The fuel consumption increases. The pressure of the three-way catalytic converter boosts, and it can even be damaged. The engine may have weak acceleration, and the power increases slowly.

●  Signal interruption

In addition to the abnormal signal, signal interruption is another common issue in the sensor. Compared to the case of signal abnormality, signal disconnection has little effect on the engine.

There are simple reasons. To control the injection amount, the signals from the mass air sensor, throttle position sensor, water temperature sensor and others help the engine ECU control the injection amount.

Therefore, after the mass air flow sensor signal is disconnected, the ECU will automatically respond and no longer use this one as a reference signal. So it won't have much effect on the car's fuel injection.

However, when you press the accelerator pedal, the throttle threshold increases, and the vacuum of the intake manifold changes. However, the air flow meter signal is disconnected, and the intake pressure cannot be detected. This causes an inaccurate fuel injection for a short period (before the ECU isolates the air flow meter signal), which leads to an inaccurate engine air-fuel ratio, affecting the engine power and fuel economy.

4. Inspection

There are two ways to determine whether the air flow meter is damaged. One is to use a multimeter, oscilloscope or other measuring tools. They check every signal wire, firewire, and zero wire to determine whether the air flow meter is damaged.

Another method is simple. Disconnect the air flow meter plug, and unplug the sensor. In this situation, if the issues aren't resolved, there is nothing wrong with the mass air flow sensor. Conversely, when the engine becomes shaky after unplugging the sensor, the symptoms increases significantly. It means that the air flow meter itself has poor contact. The signal misalignment is a trouble.

Another method is simple. Disconnect the air flow meter plug, and unplug the sensor. In this situation, if the issues aren't resolved, there is nothing wrong with the mass air flow sensor. Conversely, the symptoms increase significantly when the engine becomes shaky after unplugging the sensor. It means that the air flow meter itself has poor contact. The signal misalignment is trouble.

5. Keep It Clean

The mass air flow sensor has a compact structure. There isn't much mechanical pressure in the installation position. So the mass air flow sensor isn't vulnerable.

However, the air flow meter damage is generally due to dirt. The air flow meter probe can be damaged. If you want to avoid problems with the mass air flow sensor, it is best to maintain the cleanliness of the air filter and keep the incoming air clean.

6. Reasons for Choosing Delcoribo Mass Air Flow Sensor

Stable engine performance can reduce unnecessary fuel consumption. That’s why we make engine parts work in cooperation for the best operation. Delcoribo mass air flow sensors are competent for heavy tasks in harsh working conditions after passing rigorous tests.

We have a professional team working hard to ensure contamination resistance. Vehicles need accurate intake air value to inject exact amount of fuel. It is terrible to suffer redundant fuel consumption due to improper air-fuel mixture. Delcoribo enables our products to defend against dust, oil and vibration. We provide real good sensors for automobiles.

Engine combustion is a complex process. Our mass air flow sensors always transmit correct signals to the ECU, which helps to improve the economical operation. You can find these components easy to replace the old ones. There is a large selection to meet your need.