Caprice V8-265 4.3L VIN W MFI (1995)
Knock Sensor: Description and Operation
Knock Sensor (KS) Sensor
Knock Sensor Cut-away
Varying octane levels in today's gasoline can cause detonation in high performance engines. Detonation is sometimes called spark knock. To control
spark knock, a Knock Sensor (KS) system is used. This system is designed to retard spark timing up to 20° to reduce spark knock in the engine. This
allows the engine to use maximum spark advance to improve driveability and fuel economy.
The knock sensor system is used to detect engine detonation. The Powertrain Control Module (PCM) will retard the spark timing based on signals from
the KS module. The knock sensors produce an AC voltage which is sent to the KS module. The amount of AC voltage produced by the sensors is
determined by the amount of knock. This signal voltage is input to the PCM. The PCM then adjusts the Ignition Control (IC) to reduce spark knocking.
