Why does the car vibrate after starting?
2 Answers
Here is an introduction to car vibration after starting: 1. Carbon deposits in the engine. When there is too much carbon deposit in the engine, it can cause poor engine performance and various malfunctions. Excessive carbon deposits inside the engine can cause the gasoline sprayed by the cold start injector to be largely absorbed by the carbon deposits, resulting in a lean air-fuel mixture during cold starts, making it difficult to start. Only after the carbon deposits become saturated with gasoline does the car start easily. After starting, the gasoline adsorbed on the carbon deposits is drawn into the cylinder by the engine's vacuum suction for combustion, enriching the air-fuel mixture. The engine's combustible mixture alternates between lean and rich, causing idle vibration after a cold start. Solution: Clean the fuel system and check if the idle air control valve has carbon deposits that need cleaning. 2. For vehicles with 3 cylinders or fewer, some vibration is normal. If it is more severe than usual, check the engine compartment for any abnormalities. Common symptoms include burnt spark plugs, excessive spark plug gaps, or loose spark plugs. 3. Sometimes, insufficient tire pressure or balance issues can cause the car to shake. In such cases, carefully check the tire pressure and look for any abnormal tire wear.
Having driven for so many years, it's quite common for a car to vibrate after starting, especially in winter or when the car hasn't been used for a while. The vibration is mainly because the engine hasn't warmed up yet, low oil temperature increases friction between internal components, or there might be an issue with the ignition system, like dirty spark plugs causing poor ignition. If the engine mounts are cracked or worn out, the entire engine support becomes unstable, leading to vibrations. Sometimes, not changing the oil on time can make it too thick, affecting performance. I've encountered these situations quite often. Letting the engine run for a few minutes after a cold start can reduce the vibration, but if it persists or becomes severe, it's best to take it to a mechanic before parts fail completely. Regular maintenance like changing the oil and spark plugs is crucial—prevention is always cheaper and less hassle than repairs.
