Crossfire SRT-6 V6-3.2L SC VIN N (2005)
Knock Sensor: Description and Operation
The 3.2L engine is equipped with two knock sensors. The knock sensors bolt onto the cylinder block below the intake manifold in the engine valley.
They are designed to detect engine vibration that is caused by detonation.
Two knock sensors are used on the 3.2L V-6. Highly sensitive knock sensors can distinguish knocking conditions in individual cylinders and retard the
ignition timing on the cylinders that are knocking. This anti-knock control prevents damage to the engine and allows operation on lower grade fuel, but
only in emergencies. Premium grade fuel is required under normal operating conditions to ensure full power and economy. When the knock sensor
detects a knock in one of the cylinders, the sensor sends an input signal to the Powertrain Control Module (PCM). In response, the PCM retards ignition
timing for the affected cylinder.
The voltage signal produced by the knock sensor increases with the amplitude of vibration. The PCM receives the knock sensor voltage signal as an
input. If the signal rises above a predetermined level, the PCM will store that value in memory and retard ignition timing to reduce engine knock. If the
knock sensor voltage exceeds a preset value, the PCM retards ignition timing for all cylinders.
Knock sensors contain a piezoelectric material which constantly vibrates and sends an input voltage (signal) to the PCM while the engine operates. As
the intensity of the crystal's vibration increases, the knock sensor output voltage also increases.
The PCM ignores knock sensor input during engine idle conditions. Once the engine speed exceeds a specified value, knock retard is allowed.
NOTE: Over tightening or under tightening the knock sensor mounting bolts will affect knock sensor performance, possibly causing improper spark
control. Always use the specified torque when installing the knock sensors.
