Knock Sensor: Description and Operation

Knock Sensor Location:

The knock control system allows calibration of the ignition timing for normal operating conditions, while eliminating the danger of knock or detonation due to influences by heat, load, fuel quality or engine deposits.

Knock Sensor Diagram:

The knock sensor consists of a housing and piezoelectric crystal between two connector strips mounted on a steel bushing. The sensor is mounted on the engine block between #1 and #2 cylinders and is subjected to vibrations generated by knock (ping). The vibrations cause a small distortion on the surface of the piezoelectric crystal, generating a measureable voltage which is read by the control unit. When the control unit recognizes a knock condition it will then retard the ignition point as necessary to eliminate the knock depending upon the intensity.