Why does the engine shake when starting a car?
3 Answers
The reason for engine shaking when starting a car is due to a dirty throttle or faulty spark plugs. Energy conversion: An engine is a machine capable of converting other forms of energy into mechanical energy, including internal combustion engines (reciprocating piston engines), external combustion engines (Stirling engines, steam engines, etc.), jet engines, electric motors, etc. For example, an internal combustion engine typically converts chemical energy into mechanical energy. Device: An engine can refer to both a power generation device and the entire machine including the power unit (e.g., gasoline engines, aircraft engines). The engine was first invented in the UK, so the concept of an engine originates from English, with its original meaning referring to "a mechanical device that generates power."
Oh, you ran into this situation? Reminds me of when I first got my old ride—cold starts made the steering wheel shake like a massage chair. Most likely it's due to worn engine mounts. These things are like shock-absorbing insoles for the engine; over time they harden and crack, letting all the engine vibrations travel straight into the cabin. Could also be time to replace the spark plugs—last time my car shook badly, swapping in a set of double iridium plugs made it steady as a rock. A dirty throttle body is another common culprit, especially for cars that mostly drive in the city. Carbon buildup clogs the valve gaps, making airflow as unstable as a runner gasping for breath. When checking, remember to test both cold and warm starts. If it still shakes after warming up, chances are the ignition coils are the issue.
My friend's car just developed this issue the day before yesterday, with the tachometer needle dancing around. From a repair perspective, the first thing to check is the air-fuel mixture concentration. If the cold start fuel compensation is too high or the oxygen sensor has a delay, unburned gasoline will puff out black smoke like damp firewood. Next is the ignition system - excessively wide spark plug gaps or leaking ignition coils can cause misfires and shaking. Another possibility is carbon buildup in the engine; coke deposits on piston crowns act like a quilt over the combustion chamber, causing abnormal compression ratios and knocking. Remember to check if the air filter is clogged - restricted airflow makes the engine struggle. If left unchecked, these issues may trigger the check engine light. Don't wait until failing emissions tests at annual inspection to address them.
