How to Replace a Car Mass Air Flow Sensor (MAF)
The mass air flow sensor or MAF is a vital part to your cars computer system. This device is used to measure the amount of air being processed through the engine at any given second. There are two styles of mass air flow sensors. The more popular type is designed with a "hot wire" that when air travels across it the ohms reading changes. The system computer PCM powertrain control module uses this feedback information and adjusts the fuel and ignition systems accordingly. The other style of mass air flow sensor uses a mechanical door that blocks the air passage when the motor is not running and then opens when the motor is running.
The faster the engine is running the more the door opens. This mechanical style of mass air flow sensor is designed with a rheostat which is connected to the computer. Never the less, both of these mass air flow sensors can wear out or become contaminated. In most cases changing a mass air flow sensor is a relatively an easy job and should only take about twenty minutes. (Note: not all cars are equipped with a mass air flow sensor, consult arepair manual if you are unsure of your cars sensor location).
Step 1 - Release both the primary and secondary hood latch releases. Raise the car's hood and support it with a prop rod if needed.
Step 2 - Locate the mass air flow sensor in the intake tube or near the air filter housing.
Step 3 - Remove the mounting hose clamps or rings holding the air tube to the sensor, then remove the tube.
Step 4 - Disconnect the electrical connector from the mass air flow sensor
Step 5 - Remove the three or four mounting bolts holding the sensor to the body plate. (Some Ford mass air flow sensors are located inside the air filter housing).
Step 6 - Loosen and remove the mounting screws holding the sensor to the case, if any.
Step 7 - Match up the new mass air flow sensor to the old unit, particularly the electrical connector.
Step 8 - Install the new mass air flow sensor and reassemble.
Note: When the engine first starts with a new mass air flow sensor it might not run correctly, allow time for the system to recalibrate, about five minutes of engine run time.