What are the effects of secondary ignition?

[JasonLee]

Secondary ignition can cause certain damage to the starter motor and ignition coil. Here is the relevant content introduction: 1. Reason: Starting the car again when it is already running will cause the starter motor to grind gears, generally causing damage to the starter gear of the starter motor and the flywheel ring gear of the engine. However, this damage is only limited to the flywheel ring gear and the starter pinion, and the starter will experience excessive local wear, but it will not harm important components such as the engine and transmission. 2. External force system: In order to bring the stationary engine into working condition, it is necessary to first rotate the engine crankshaft with an external force to make the pistons start moving up and down, allowing the cylinder to inhale combustible mixture gas, and then sequentially enter the subsequent working cycles. The system that relies on this external force is the starting system.

[StAngelo]

That day I was driving home and forgot the engine was still running, so I turned the key to start it again, only to be startled by a harsh grinding noise. The mechanic later explained that this is called a double start, which most easily damages the starter gear and flywheel gear—these components are only meant to work during startup, and trying to start the engine while it's already running is like forcing metal against metal. The gears can collide violently, potentially wearing them down or even breaking them. Over time, the starter could be ruined, and repairs could cost thousands. Plus, it puts extra strain on the battery—the additional current draw can cause voltage instability, affecting the entire vehicle's electrical system. Now, I’ve made it a habit to check the tachometer needle before starting the engine, ensuring the RPM is at zero before turning the key to avoid such unnecessary trouble. Also, older cars are more prone to issues from this, so during regular maintenance, I have the mechanic check the gear condition to prevent any potential damage from worsening.

[RyderDella]

I've been driving for decades and have experienced several instances of secondary ignition. I remember one time at a highway rest stop, I mistakenly thought the engine had stalled. The moment I tried to restart it, I was nearly scared to death—the starter gear made a loud clanking noise, and the whole car shook violently. The mechanic told me this not only wastes battery life but also poses significant safety hazards: if the gear isn't properly engaged during startup, especially in automatic transmission cars, the vehicle might suddenly lurch out of control. I advise young car owners not to rush to start the engine. First, listen for smooth engine sounds or glance at the dashboard to see if the lights are off. After developing this habit, I haven't had any mishaps in recent years, saving a lot on repairs. Another tip: if you hear a strange, tearing-like sound when trying to start an already running engine, immediately release the key to minimize damage.

[ElleAnn]

As a mechanic, I often encounter starter failures, mostly caused by secondary ignition. The small gear inside the starter and the large flywheel gear are designed only for the instantaneous load during startup. Forcing ignition while the engine is running causes violent gear collisions, leading to surface wear at best or complete shattering at worst. I've seen many customers spend heavily on replacing components due to this, sometimes even affecting the ignition system. My advice is to ensure the key returns to position or the engine isn't running before ignition—a simple method is checking that dashboard lights are off. This prevents future troubles. Also, vehicles with automatic climate control are more sensitive during ignition, and secondary actions have greater impact. In most cases I've repaired, this factor was frequently overlooked.