In one embodiment, a system includes an engine control system configured to control an engine. The engine control system comprises a processor configured to receive a vibration signal sensed by a knock sensor disposed in an engine. The processor is further configured to correlate the vibration signal with a fingerprint having at least an ADSR envelope indicative of the operating event of a valve train of the combustion engine, analyze the vibration signal with a statistical valve train model, or a combination thereof. The processor is also configured to detect if the operating event has occurred based on correlating of the noise signal with the fingerprint, based on analyzing the vibration signal with a statistical valve train model, or a combination thereof, and to control the valve train based on the operating event.