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.

[BentleyLynn]

I've encountered many issues with cold start engine shaking, especially when starting a Magotan on winter mornings. The main reason is carbon buildup in the engine, which affects combustion efficiency, making it harder to ignite the air-fuel mixture evenly when the engine is cold. Additionally, worn spark plugs or faulty ignition coils can cause weak ignition; clogged fuel injectors may lead to uneven fuel spray; and a dirty air filter can restrict sufficient air intake. Worn engine mounts can also make cold start vibrations more noticeable. Poor fuel quality or water contamination may contribute to these problems. I recommend visiting a professional workshop for inspection, including carbon cleaning and replacing aged components, while also using high-quality fuel during regular maintenance.

[Barros]

My Magotan also experienced shaking during cold starts, which was very uncomfortable to drive. After inspection, it was found that there was a minor issue with the fuel injection system—the fuel injector was clogged, causing inaccurate fuel injection. Additionally, the air-fuel ratio sensor signal was unstable, leading to improper computer control. Insufficient fuel pump pressure in cold weather can also cause shaking. It wasn’t difficult to fix; after cleaning the relevant components, the situation improved significantly. The mechanic also reminded me to warm up the car for a short while in cold temperatures to ensure the lubrication system works smoothly, which can help reduce such issues.

[MiguelAnn]

Cold start shaking in cars is commonly caused by fuel system malfunctions. For example, clogged or leaking fuel injectors affect fuel quantity control; enlarged spark plug electrode gaps result in weak ignition; and excessive carbon buildup on engine intake/exhaust valves leads to poor sealing during cold starts, causing low compression pressure and shaking. Faulty sensors like the coolant temperature probe can also misreport temperatures, causing the ECU to incorrectly adjust fuel injection. Inspecting these points usually resolves the issue, making regular cleaning and maintenance crucial.