Quest 1995-1996

Knock Sensor

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Operation



Specific to:

Mercury Villager 1993-2000

Nissan Quest 1993-2000

The Knock Sensor (KS) is located on the engine block under the intake manifold. The sensor monitors preignition, or spark knock, and sends the signal to the PCM. The PCM responds by adjusting ignition and fuel timing until knocking is stopped. Vibrations in the engine are sensed by the piezoelectric element and weight in the KS as vibrational pressure. The vibrational pressure is converted to a voltage signal, which is sent to the PCM.

Click image to see an enlarged view

Fig. Knock sensor location with a view of the internal components

Removal & Installation



Specific to:

Mercury Villager 1993-2000

Nissan Quest 1993-2000

  1. Remove the lower intake manifold. Please refer to Engine and Engine Overhaul, Engine Mechanical, Intake Manifold, Removal and Installation, Lower Intake Manifold for the procedure.
  2.  
  3. Remove the coolant crossover tube.
  4.  
  5. Disconnect the KS electrical connector.
  6.  
  7. Remove the KS bolt and remove the sensor.
  8.  
  9. The installation is the reverse of removal.
  10.  

Testing



Specific to:

Mercury Villager 1993-2000

Nissan Quest 1993-2000

  1. With the ignition switch OFF , disconnect the KS electrical connector.
  2.  
  3. Using an ohmmeter that can measure more than 10 megohms (10 M scale), connect the leads between terminal 1 of the sensor and the negative battery terminal or engine ground.
  4.  
  5. Observe the ohmmeter reading. The reading should be 500-620 kilohms. If not, replace the sensor.

    Click image to see an enlarged view

    Fig. Ohmmeter connections for knock sensor testing

  6.  

 
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