GM Camaro/Firebird 1993-1998 Repair Guide

Knock Sensor (KS)

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OPERATION



Some vehicles use two knock sensors.

The knock sensor is usually mounted to the right lower side of the engine block. However, on 1998 5.7L engines, the Knock Sensors are located under the intake manifold. When spark knock or pinging is present, the sensor produces a voltage signal which is sent to the PCM. The PCM will then retard the ignition timing based on these signals.

TESTING



  1. Connect a timing light to the vehicle, then start the engine.
  2.  
  3. Check that the timing is correct before testing the knock sensor operation.
  4.  
  5. If the timing is correct, tap on the front of the engine block with a metal object while observing the timing to see if the timing retards.
  6.  
  7. If the timing does not retard, the knock sensor may be defective.
  8.  

REMOVAL & INSTALLATION



Except 1998 5.7L Engine

See Figures 1, 2 and 3

  1. Disconnect the negative battery cable.
  2.  
  3. Raise and properly support the vehicle.
  4.  
  5. Position a suitable drain pan under the vehicle, then drain the engine coolant.
  6.  
  7. Disconnect the knock sensor wiring harness. On the 1998 3.8L engine, you must detach the connectors from the bank 1 and bank 2 knock sensors.
  8.  
  9. Remove the knock sensor from the engine block.
  10.  


CAUTION
The knock sensor is mounted in the engine block cooling passage. Engine coolant in the block will drain when the sensor is removed.



Click image to see an enlarged view

Fig. Fig. 1: On the 3.8L engine, detach the bank 1 knock sensor connector ...



Click image to see an enlarged view

Fig. Fig. 2: ... then detach the bank 2 knock sensor connector



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Fig. Fig. 3: Knock sensor mounting-1996-97 3.8L engine

  1. Installation is the reverse of removal. Tighten the sensor to 14 ft. lbs. (19Nm).
  2.  

1998 5.7L Engine

See Figures 4 and 5

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the intake manifold.
  4.  
  5. Detach the knock sensor electrical connector(s), then remove the knock sensor(s).
  6.  
  7. Installation is the reverse of the removal procedure. Tighten the sensor(s) to 11 ft. lbs. 15 Nm.
  8.  



Click image to see an enlarged view

Fig. Fig. 4: Detach the knock sensor electrical connectors-1998 5.7L engine



Click image to see an enlarged view

Fig. Fig. 5: Remove the knock sensor(s) from the engine-1998 5.7L engine

 
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