Spark Control Causes
The Electronic Spark Control, also called the Knock Sensor, is an electronic device built by General Motors to help regulate the timing inside of the engine. When combustion inside the engine does not fire properly, a “spark knock” or abnormal vibration can occur. If these vibrations caused by misfires are not reduced, they can cause significant damage to the engine components. Modern engines are tuned to reduce these knocks as much as possible, however they can still occur under certain conditions. As an engine ages, its timing can degrade, leading to knocks. Outside factors such as the humidity or altitude where the engine is operating can also cause timing issues. Electronic Spark Control compensates for these occurrences.
Spark Control Detection
The vibrations that can potentially damage an engine also help make knocks easy to detect. Because these vibrations resonate at a particular frequency, they can be sensed and located when they occur. Knock sensors inside an engine contain piezoelectric crystals tuned to this frequency, and generate electric signals when the vibration occurs.