Mazda RX-8 2004-06

Mass Air Flow (MAF) Sensor

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Operation



The Mass Air Flow (MAF) sensor directly measures the amount of the air flowing into the engine. The sensor is mounted between the air cleaner assembly and the air cleaner outlet tube.

The sensor utilizes a hot wire-sensing element to measure the amount of air entering the engine. The sensor does this by sending a signal, generated by the sensor when the incoming air cools the hot wire down, to the PCM. The signal is used by the PCM to calculate the injector pulse width, which controls the air/fuel ratio in the engine. The sensor and plastic housing are integral and must be replaced if found to be defective.

The sensing element (hot wire) is a thin platinum wire wound on a ceramic bobbin and coated with glass. This hot wire is maintained at 392°F (200°C) above the ambient temperature as measured by a constant -cold wire''.

Removal & Installation



  1. Remove the air cleaner outlet tube.
  2.  
  3. Disconnect the MAF sensor electrical connector.
  4.  
  5. Remove the attaching four nuts and the MAF sensor.
  6.  
  7. Installation is the reverse of the removal procedure.

    Click image to see an enlarged view

    Fig. MAF sensor removal

  8.  

Testing



  1. Remove the MAF/IAT sensor without disconnect the MAF/IAT sensor connector.
  2.  
  3. Turn the ignition switch to ON position.
  4.  
  5. As the air gradually approaches the MAF detection part of the MAF/IAT sensor, verify that the voltage at PCM terminal 5N (WDS PID: MAF) varies. Standard value:

    AT-4.4-5.3 g/s at idle
     
    AT-9.5-12.5 g/s at 2500 RPM
     
    MT-3.8-4.7 g/s at idle
     
    MT-8.7-11.7 g/s at 2500 RPM
     

  6.  
  7. If not as specified, the MAF sensor must be replaced.
  8.  

 
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