Why does the car shake severely when just started?
1 Answers
If severe shaking is noticed after starting the car, it indicates an abnormal condition in the vehicle. It is important to stop and inspect promptly to avoid more serious hazards. Below are solutions for severe shaking when the car is just started: 1. Carbon buildup in the engine is unavoidable during operation, but excessive carbon deposits can lead to poor engine performance and various malfunctions. When there is too much carbon buildup inside the engine, the gasoline sprayed by the cold start injector can be largely absorbed by the carbon deposits, resulting in an overly lean air-fuel mixture during cold starts. This makes starting difficult until the carbon deposits become saturated with gasoline, making it easier to start. After starting, the gasoline adsorbed on the carbon deposits is sucked into the cylinders by the engine's vacuum force for combustion, enriching the air-fuel mixture. The fluctuating lean and rich air-fuel mixture causes idle shaking after a cold start. Solution: Clean the fuel system and inspect the idle control valve for carbon buildup, which should be cleaned if necessary. 2. For vehicles with 3 cylinders or fewer, shaking is mostly normal, as 3-cylinder engines inherently shake more severely. For vehicles with 4 cylinders or more, if the shaking is worse than usual, inspect the engine bay for any abnormalities, such as a cylinder not working or multiple cylinders performing poorly. Common symptoms include excessively large spark plug gaps or loose spark plugs, which can cause shaking. In such cases, stop the vehicle and carefully inspect the spark plugs for integrity. If tools are available, remove the spark plugs for inspection. Other issues like poor fuel supply or inadequate lubrication may also cause shaking. If unable to resolve these issues, promptly visit a repair shop. 3. Sometimes, insufficient tire pressure or balance issues can cause the vehicle to shake. In such cases, carefully check the tire pressure and look for any abnormal tire wear.
