A speed-determining system in an internal combustion engine is disclosed. The internal combustion engine includes a crankshaft, a camshaft, and an engine control module (ECM). The system includes a first gear that rotates with the crankshaft and a second gear attached to the camshaft. At least one idler gear is operatively meshed with the first gear and the second gear. A fuel pump gear, meshed with the idler gear, is driven proportionally to the first gear and the second gear. The fuel pump gear includes a transversal face, a circumferential lip portion, and a number of notches along the circumferential lip portion. A proximity sensor, in communication with the ECM, is spaced from the second gear. A rotation of the fuel pump gear moves the notches relative to the proximity sensor, triggering the proximity sensor to register movement of the fuel pump gear and calculate at least a camshaft speed.