What Causes the Volkswagen Magotan to Shake During Cold Starts?

[DelAdeline]

Here are the specific reasons why the Volkswagen Magotan shakes during cold starts: 1. Low ignition energy. The temperature inside the engine is insufficient, and the temperature of fuel and lubricating oil does not meet the requirements. Therefore, more fuel should be injected during cold starts to meet the power demand. The larger the spark plug gap, the lower the ignition energy. At low temperatures, fuel atomization is poor, requiring higher ignition energy. Over time, the ignition gap of the spark plug tends to increase, leading to a decrease in ignition energy, which affects the power performance and causes the car to shake. 2. Carbon deposits on the valves and intake ports. If carbon deposits accumulate on the valves and intake ports of the engine, they can absorb an appropriate amount of fuel, causing the ECU to make incorrect judgments. For example, the ECU may control the injection of 100 units of fuel-air mixture, but only 90 units actually enter the cylinder. Even if the remaining 90 units of mixture burn completely, the required power performance is not achieved, resulting in shaking. 3. Incorrect air-fuel mixture ratio. The air-fuel mixture ratio may be inaccurately adjusted, occurring in both open-loop and closed-loop control systems. In vehicles with closed-loop control, the oxygen sensor's minimum operating temperature is 370 degrees Celsius. If the car is just started, the exhaust pipe temperature may not reach 370 degrees Celsius, preventing the oxygen sensor from functioning. This leads to ECU misjudgment, causing errors in the control of the air-fuel mixture and ignition timing, thereby reducing the car's power output and resulting in shaking.