A Mass Airflow Sensor (MAF) is used to measure the amount of air entering an engine. It is important to measure air so that the ECU can calculate the correct amount of fuel to inject into the combustion chamber to achieve the optimum air/fuel ratio. Because of the MAF’s important role, it should be attended to regularly, just as you would an air filter.
MAFs got their name because they are designed to calculate the entire mass of air rather than just the flow rate. This helps the ECU better respond to differences in air density from changes in temperature and air pressure. However, Air Intake Temperature (IAT) sensors and in many cases Mass Pressure (MAP) sensors are still required.
The most common MAF type is the hot wire. This pre-heated filament, when hit with air, cools and creates a change in electrical resistance. This subsequently results in a change of the voltage signal (normally between 0 and 5 volts) sent to the ECU.
Over time, the hot wire on the sensor can accumulate debris, dust, and sometimes oil particulates, especially if an aftermarket filter or induction kit is fitted, as the filter is normally coated with an oil to trap fine dust. As a result, this oil and debris can make its way onto the sensor, which in turn affects the accuracy of the airflow signal to the ECU. This can result in poor engine running, hesitation, increased emissions, reduced MPG, and so on.
Unfortunately, even the most modern ECUs are unable to detect this degradation of performance. An error code or warning light will only appear if the unit has failed completely.
The solution is to clean the MAF at each service schedule with a designated MAF cleaner. Standard electrical contact cleaners also are effective, but make sure that they do not leave any residue. Also, bear in mind that they usually contain a single basic solvent whereas professional MAF cleaners contain a blend of multiple solvents specifically for the type of debris that needs to be removed, making the job a little easier.
We recommend Archoil AR2810 MAF Cleaner as it contains 300ml of the best solvents available for exactly this task. It also is completely safe for all MAF materials and plastics, leaves absolutely zero residue, and is comparable in cost to basic contact cleaners when considering the size of the can.
If you require any expert advice or help, please don’t hesitate to contact us and either I or a member of my team will be pleased to assist you.