A pre-engaged piston starter system of an automobile vehicle includes an engine having a flywheel to start the engine connected to the engine by an engine shaft. A starter motor provides rotational energy to a starter gear. A pinion gear transfers rotational energy of the starter gear to the flywheel. A solenoid is energized to shift the pinion gear to an engaged position between the flywheel and the starter gear. An auto-stop mode is entered when an engine speed is decreased below a calibrated threshold speed defining approximately 250 rpm. A calculated pinion pre-engagement engine speed allows engagement of the pinion gear when the engine speed is below the calibrated threshold speed.