Knock Sensor
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 1987 Volkswagen Scirocco, 1987 Volkswagen Quantum, 1987 Volkswagen Jetta, 1987 Volkswagen Golf, and 1987 Volkswagen GTI. However, it is still accessible from the selected car via links, so may be relevant.
The knock sensor is mounted at the front of the cylinder block. A 3 wire connector transmits signals to the knock sensor control unit and to the TCI. The sensor mounting bolt torque influences sensor function. See REMOVAL & INSTALLATION section of this article. The knock sensors signal will advance or retard ignition timing to control combustion chamber pre-ignition.