What Causes Engine Shaking During Cold Starts in Winter?
2 Answers
Low engine coolant temperature is a common cause of shaking during cold starts in winter, which is why vehicle warm-up is essential before driving in cold weather. Below are the primary reasons for engine shaking during startup: 1. Low ambient temperature: Cold temperatures lower the exhaust pipe temperature, and since oxygen sensors have a minimum operating temperature, the vehicle's ECU cannot obtain accurate data. This leads to errors in ignition and air-fuel mixture control, resulting in reduced power output and engine shaking. 2. Worn spark plugs: When spark plugs age, their ignition gaps become inconsistent, causing power deviations among cylinders. This affects engine performance and induces shaking. 3. Carbon buildup: Throttle valve carbon deposits have adhesive properties, preventing the required gasoline volume for combustion. This creates a shaking phenomenon.
When starting a cold car in winter, the shaking can be quite severe. After decades of driving, I've found this to be quite common. The engine oil thickens in low temperatures, reducing its lubrication effectiveness, which increases engine friction during startup and naturally causes shaking. Additionally, if the spark plugs are old or the ignition coils are faulty, the ignition becomes weak, leading to incomplete gasoline combustion and resulting in shaking. Carbon buildup is a major factor; long-term accumulation makes the engine run unevenly, especially noticeable in winter's low temperatures. To reduce shaking, I recommend switching to a low-viscosity oil suitable for cold weather, such as 5W-30, before the cold sets in. Regularly check the spark plugs and replace them every few tens of thousands of kilometers—don't skimp on this. Cleaning the throttle body and fuel lines can also help. After starting the car, don't rush to drive off; let it warm up for a minute or two to allow the oil to circulate properly.
