- Ignition: When you turn the key or press the start button in your vehicle, the ignition system activates. This sends an electrical signal to the starter motor.
- Starting: The starter motor engages with the vehicle's flywheel (connected to the crankshaft) and begins to turn it. This initial turning is what causes the engine's RPM to jump.
- Fuel Injection: As the starter motor turns the engine, the vehicle's fuel injection system delivers fuel into the combustion chambers of the engine.
- Combustion: The spark plugs generate sparks within the combustion chambers, igniting the fuel-air mixture, which results in a series of small explosions. These explosions drive the pistons, converting the reciprocating motion into rotational motion.
- Idling: As the engine starts running, the rpm is typically higher than the normal idle speed due to the initial cranking. However, it quickly settles down to its normal idling range.
So, the initial shoot-up in RPM when a standing vehicle is started is primarily due to the starter motor engaging and turning the engine's crankshaft and the subsequent combustion process. Once the engine is running smoothly, the RPM should regulate to a stable idle speed.
