GM Lumina/Grand Prix/Cutlass Supreme/Regal 1988-1996

Mass Air Flow (MAF) Sensor

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OPERATION



The Mass Air Flow (MAF) sensor measures the amount of air entering the engine during a given time. The ECM uses the mass airflow information for fuel delivery calculations. A large quantity of air entering the engine indicates an acceleration or high load situation, while a small quantity of air indicates deceleration or idle.

TESTING



See Figure 1

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Fig. Fig. 1: Mass Air Flow (MAF) sensor wiring diagram

  1. Backprobe with a high impedance voltmeter between MAF sensor terminals C and B .
  2.  
  3. With the ignition ON engine OFF, verify that battery voltage is present.
  4.  
  5. If the voltage is not as specified, either the wiring to the MAF sensor, fuse or the ECM may be faulty. Correct any wiring or ECM faults before continuing the test.
  6.  
  7. Disconnect the voltmeter and backprobe with a frequency meter between MAF sensor terminals A and B .
  8.  
  9. Start the engine and wait until it reaches normal idle speed and verify that the MAF sensor output is approximately 2000 Hz.
  10.  
  11. Slowly raise engine speed up to maximum recommended rpm and verify that the MAF sensor output rises smoothly to approximately 8000 Hz.
  12.  
  13. If MAF sensor output is not as specified the sensor may be faulty.
  14.  

REMOVAL & INSTALLATION



See Figures 2 and 3

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Fig. Fig. 2: The MAF sensor is mounted to the throttle body-3.8L engine



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Fig. Fig. 3: Exploded view of the MAF sensor

  1. Disconnect the negative battery cable.
  2.  
  3. Detach the electrical connector from the MAF sensor.
  4.  
  5. For the 3.1L engine, remove the MAF sensor from the air cleaner housing.
  6.  
  7. For the 3.4L engine, remove the air cleaner and duct assembly. Loosen the sensor retaining clamp and remove the sensor.
  8.  
  9. For the 3.8L engine, remove the fresh air duct from the throttle body and air cleaner assembly. Remove the retaining screws, then remove the MAF sensor from the throttle body.
  10.  

To install:
  1. For the 3.8L engine, position the MAF sensor to the throttle body and secure with the 3 retaining screws.
  2.  
  3. For the 3.4L engine, position the sensor and fasten the retaining clamp. Install the air cleaner and duct assembly.
  4.  
  5. For the 3.1L engine, carefully install the MAF sensor to the air inlet grommet. Install the MAF sensor to the air inlet duct.
  6.  
  7. Attach the electrical connector, then connect the negative battery cable.
  8.  

 
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