The function of the mass air flow sensor is to measure the amount of air entering the engine.

It serves as a function to allow the computer to calculate the proper air and fuel mixture which should be close to 14.7 air to 1 part fuel. A mass air flow typically last between 80,000 miles to 150,000 miles. Proper maintenance of the mass air flow and cleaning it will help prolong its life. However, there are a few vehicle symptoms that will tell you when it is time to replace the air flow sensor.

The first symptom is hard starting. Usually, it may take a few tries to crank the engine over. If this is the case, suspect a faulty air flow sensor. Remove the sensor from the inlet tube or air filter box whichever the sensor is mounted on. Take a look inside the sensor for a thin filament. If the filament is dirty or contaminated then the sensor may be faulty. However, before condemning a faulty sensor, use an approved air flow sensor cleaner and try spraying the filament. Next, reinstall the air flow. If the vehicle starts up normally, then the fault is due to a dirty mass air flow and not a failed sensor.

There are more symptoms that may display when the sensor is starting to act up. For example, sometime the vehicle may hesitate when in motion or sitting at the stop light. It may also jerk when trying to give it gas. In that case, the sensor may be faulty. Moreover, a completely dead sensor may prevent the automatic transmission from properly engaging. That means, during cold start up, the automatic transmission may not respond in drive and a delay might occur preventing the vehicle from moving.

Furthermore, if you experience a complete lack of engine performance or rough jerk, you may want to inspect the air inlet tube. Sometime, a cracked inlet tube will allow un-metered air to enter the engine. If that is the case, the air flow sensor is unable to properly measure the incoming air; therefore the engine may increase fuel or sometime decrease fuel thus causing a performance problem. Do not be confused by a hard jerk for a transmission problem. Always visually inspect all components, wires, and scan the vehicle for engine code before condemning a faulty mass air flow sensor.

If you have any questions about the mass air flow sensor, or want to schedule a service give us a call today at Jorge Alonso Auto Repair!