Oct 03, 2019 · Ford Fusion Whining Noise When Accelerating. A whining sound when accelerating is almost always caused by a bad accessory attached to your Fusion’s engine. Here are the most common causes of whining noises when accelerating: 1. Bad Alternator. When an alternator is going bad, it’ll often begin to put out a high pitched whining sound. It should also be accompanied by the battery light.