A system comprises a generator and an engine coupled thereto. The engine is configured to provide mechanical power to the generator. A controller is coupled to the engine and the generator and is configured to compare an engine operating parameter value to a load demand value indicative of a load exerted by the generator on the engine. The controller determines that the engine operating parameter value fails to match the load demand value. The controller determines an engine operating parameter threshold value at which the engine operating parameter value failed to match the load demand value, and sets the engine operating parameter threshold value as a maximum allowable engine operating parameter value for the engine.