What happens if you crank the engine for almost 2 seconds while car is already on?

Cranking the engine for almost 2 seconds while the car is already running will likely cause nothing significant to happen, assuming the starter motor is functioning normally. The starter motor is designed to only engage for a brief period to initiate the engine's startup. Once the engine is running, the starter is disengaged. Forcing it to crank while the engine is already running might:

* Produce a loud grinding or clicking noise: This is the sound of the starter motor trying to engage with a flywheel that's already spinning rapidly. This is the most likely outcome.

* Potentially damage the starter motor: Repeatedly doing this could put extra wear and tear on the starter motor components, eventually leading to failure. A single instance is unlikely to cause significant damage.

* Nothing noticeable: In some cases, especially if the starter motor's solenoid is properly designed, the starter might not even engage at all.

In short, it's not good for the starter motor, and the noise will be unpleasant. It's best to avoid doing this.