A controller associated with an engine monitoring system may determine a voltage value concerning at least one supercapacitor associated with the engine monitoring system. The controller may selectively cause, based on determining whether the voltage value satisfies a voltage value threshold, the at least one supercapacitor, or a battery associated with the engine monitoring system, to provide electrical power to a sensor system associated with the engine monitoring system. The controller may obtain, from the sensor system, vibration information relating to an engine associated with the engine monitoring system and pressure information relating to a crankcase of the engine. The controller may determine, based on the vibration information and the pressure information, engine speed information related to the engine and may send the engine speed information to a monitoring device.