Poor engine start, unstable operation of the engine in the neutral gear or jerking on acceleration are the most common symptoms of a failure of the mass flow sensor, commonly referred to as the flowrate sensor. Check if the sensor operates properly if you observe any of these symptoms. Sometimes the sensor may be fine, but there may be leaks in the inlet system. Accurate diagnosis of a failure of the sensor requires connecting the engine to a diagnostic computer.
What is the air flow meter?
The air flow meter is a device fitted on the inlet duct, between the air filter and the inlet manifold. It informs the engine controller about the amount of air sucked in by the engine. On this basis, the computer calculates the amount of fuel that must be provided by the injectors.
What causes the air flow meter to malfunction?
The air flow meter usually operates as the so-called hot film, i.e. a small wire acting as a resistor. The wire is heated up as a result of an electric current flow, while the air flowing around it cools it down. The resistance of the meter changes with its temperature. It is based on the resistance of the entire system that the amount of the air flowing through the air flow meter is determined. The meter may burn or break down as a result of sucking in contaminants, such as dead leaves or insects.
How to check if the air flow meter operates properly?
If you suspect that the air flow meter is malfunctioning, you should first check the inlet system, which, if not tight enough, may cause air to enter the inlet manifold bypassing the air flow meter and thus affecting the air flow indications. The best way to check the air flow meter is to connect it to a diagnostic tester and read the error codes saved by the engine controller.
How is the air flow meter changed?
Changing the air flow meter requires disconnecting the electrical system plug and unfastening the clamps by means of which the body of the meter is fixed to the inlet ducts. Next, the old air flow meter is replaced with a new one, and the electrical system plug is fitted back into place.
What else to keep in mind?
It may also by necessary to delete error codes from the engine computer in order for the new meter to be able to function properly.