What is a Mass Air Flow Sensor?


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Anything and everything you need to know about a Mass Air Flow Meter. If you need to know about other autoparts checkout the rest of our presentations.

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What is a Mass Air Flow Sensor?

  1. 1. What is a Mass Air Flow Sensor?source: http://www.buyautoparts.com/howto/repair-mass-air-flow-sensor.htm
  2. 2. What is aMass Air FlowSensor? source:http://www.buyautoparts.com/h owto/what-is-a-manifold- pressure-sensor.htm
  3. 3. What is a Mass Air Flow Sensor?• A mass air flow sensor is used to find out the total of air entering a fuel-injected internal combustion engine. The air mass information is necessary for the engine control unit (ECU) to balance and deliver the correct fuel mass to the engine. Air changes its density as it expands and contracts with temperature and pressure. In automotive applications, air density varies with the ambient temperature, altitude and use of forced induction and this is an ideal application for a mass sensor.• There are two common types of mass airflow sensors in use on automotive engines. These are the vane meter and the hot wire. Neither design employs technology that measures air mass directly. However, with an additional sensor or two, the engines air mass flow rate can be accurately determined.• Both approaches are used almost exclusively on electronic fuel injection (EFI) engines. Both sensor designs output a 0.0–5.0 volt or a pulse-width modulation (PWM) signal that is proportional to the air mass flow rate, and both sensors have an intake air temperature (IAT) sensor incorporated into their housings.• When a MAF is used in conjunction with an oxygen sensor, the engines air/fuel ratio can be controlled very accurately. The MAF sensor provides the open-loop controller predicted air flow information (the measured air flow) to the ECU, and the oxygen sensor provides closed-loop feedback in order to make minor corrections to the predicted air mass. Also see MAP sensor.source: http://www.buyautoparts.com/howto/what-is-a-manifold-pressure-sensor.htm
  4. 4. Mass Air Flow Sensor Descriptionsource: http://www.buyautoparts.com/howto/mass-air-flow-sensor-description.htm
  5. 5. Mass Air Flow Sensor Description, pt 2 The mass air flow sensor works by reading the amount of air passing the aperture in a given time. This is sent to the vehicles computer via electrical pulses which can be interpreted. This will allow the computer to adjust the fuel added to the motor to create the correct internal combustion. The mass air flow sensor not only reads the amount of air flow but also the temperature of the air as well. Air temperature is just as large of a factor as the amount of air brought into the engine. The mass air sensor will have a screen to protect the unit from debris. This is not to stop dust or dirt but is intended to protect the engine from any large debris that could enter the system.source: http://www.buyautoparts.com/howto/mass-air-flow-sensor-description.htm
  6. 6. Mass Air Flow Sensor Breakdownsource: http://www.buyautoparts.com/howto/mass-air-flow-sensor-breakdown.htm
  7. 7. Mass Air Flow Sensor Breakdown The mass air flow sensor is a unit that sits at the front of the air intake measuring the oxygen content of the air entering the motor. The breakdown shown here is of the mass air flow sensor housing and shows the individual parts that make up the full unit. The unit is made up of an air temp sensor, sample tube, metal foil sensing element, electronic module and then the top cover and the flow tube. All of these elements work together to properly sense the air flow.source: http://www.buyautoparts.com/howto/mass-air-flow-sensor-description.htm
  8. 8. Mass Air Flow Sensor Locationsource: http://www.buyautoparts.com/howto/mass-air-flow-location.htm
  9. 9. Mass Air Flow Sensor Location, pt 2The modern car has many electronic systems that controlthe flow of air and fuel to the motor. The correctcombustion in the cylinders is key to the optimumperformance. The mass air flow sensor is the first sensor toread the amount of air coming into the motor. The mass airmeter can be found just after the air box on all vehicles inproduction today. The mass air meter may be located in adifferent position down the intake plenum but will alwaysbe before the throttle body. source: http://www.buyautoparts.com/howto/mass-air-flow-location.htm
  10. 10. Mass Air Flow DiagnosticsThe engine of a car is equipped with a mass air flow sensor that measures the volume anddensity of the air entering the engine. In this way the vehicles computer can calculate howmuch fuel is needed to maintain the correct fuel mixture. Problems with mass air flowsensors are common, but they rob the engine efficiency of your car, so if you notice thatyour car doesnt run you should check the MAF. This could be a start to a fail.By the time the check engine light illuminates on your dashboard, there is a symptom thatthe mass air flow sensor has failed. To be sure that this is the problem the cars computermust be checked. source: http://www.buyautoparts.com/howto/mass-air-flow-diagnostics.htm
  11. 11. Mass Air Flow Diagnostics, pt 2For MAF sensor problems you can analyze the computer yourself by attaching adigital scanner on the vehicles housing circuit and scan for any fault codes. Youcan find scanners at auto shops and if some of them work differently they all havethe same function in the end. If there are trouble codes that may indicate adeficiency in the MAF you can check them in the user instruction manual of thescanner. If you found out the problems are with the mass air flow sensor, youshould take the car to an auto service center and replace it. The MAF beingrepairable is very very rare.When your engine runs lean failure of the MAF can be the cause, but there is nota rule because it may indicate other problems than the MAF. The engine is havingtrouble running and the car is idling erratically, tries to stall or the throttle actuallydecreases at highway speed these can be symptoms of MAF failure. source: http://www.buyautoparts.com/howto/mass-air-flow-diagnostics.htm
  12. 12. Mass Air Flow Diagnostics, pt 3In some situations, mass airflow sensor begins to fail due tocontamination. In some cases there is the oil contamination and inothers there is dirt. In both cases, if the mass airflow sensorbecomes dirty the fix is to clean it or replace it.The mass airflow sensor can be removed from the cars filterhousing. Spray the sensors wires with electrical cleaner ONLY andlet the MAF air dry before you reinstall. Start the car and if theengines efficiency increases and the check engine light is off, theproblem was eliminated. source: http://www.buyautoparts.com/howto/mass-air-flow-diagnostics.htm
  13. 13. Mass Air Flow Engine Snap ShotThe engine of a car is always being monitored by many systems but all the info isfed to the main ECU. This info is available to the mechanic as an "engine snapshot" which can tell the mechanic if there are sensors that are working correctly. Ifthere is an issue with the MAF (Mass Air Flow Sensor) the readings will be way outof spec from what they are supposed to read. The mechanic can obtain thecorrect specifications from the dealership. source: http://www.buyautoparts.com/howto/mass-air-flow-diagnostics.htm
  14. 14. Air Intake Cracks and Leaks source:http://www.buyautoparts.com/ho wto/air-intake-cracks-and- leaks.htm
  15. 15. Air Intake Cracks and Leaks, pt 2• The second most common issue that causes the mass air flow sensor to read incorrectly is an air leak in the intake system. An air leak may not seem very serious but it allow dirt and debris into the engine which can cause issues down the road. When the air passes through the mass air flow sensor it is calculated at a specific volume and if there is more or less air than the calculated amount it can cause major issues for the motor. More air can cause a car to run lean which mean that there is too much air and the fuel is burning too quickly, this means the combustion will not have as much power to move the piston. Running lean can also cause the detonation to take place in a specific location in the piston which can cause damage.• With a leak that is allowing air to escape from the intake the engine will run "fat" which means there is too much fuel in the cylinders and not all of it is being burned off during combustion. If all the fuel is not burned off it can be a big problem. The unburned fuel can cause back firing and just a general lack of power. Too much fuel means the engine will bog down and in some cased become flooded which can cause the car to stall or loose significant power.• In cases of mass air flow meter issues it is always a good idea to start by inspecting the intake system. Many times the mass air is still reading right but the amount of air that it has calculated has been changed to a leak in the system. source: http://www.buyautoparts.com/howto/air-intake-cracks-and-leaks.htm
  16. 16. What is a Mass Air Flow Sensor? The EndFor more Auto How To Tips visit, http://www.buyautoparts.com/howto/If you need to purchase an auto part- Visit www.buyautoparts.com- Call 1-888-907-7225- Or send an email to sales@buyautoparts.com THANKS source: http://www.buyautoparts.com/howto/repair-mass-air-flow-sensor.htm