Why does the Magotan shake and stall during cold start?
4 Answers
Magotan shaking and stalling during cold start may be caused by the following reasons: 1. Low temperature: Insufficient temperature in the engine leads to inadequate fuel and lubricant temperatures. During cold starts, more fuel injection is required to meet power demands. Larger spark plug gaps result in weaker ignition energy. Poor fuel atomization at low temperatures requires higher ignition energy. Prolonged vehicle use can cause spark plug gaps to widen, reducing ignition energy and affecting power performance, leading to shaking. 2. Incorrect air-fuel mixture ratio: Inaccurate fuel-air mixture occurs in both open-loop and closed-loop control systems. In closed-loop control vehicles, the oxygen sensor's minimum operating temperature is 370°C. If the exhaust pipe temperature doesn't reach 370°C upon startup, the oxygen sensor won't function. This causes ECU miscalculations, resulting in errors in fuel-air mixture and ignition timing control, reducing power output and causing shaking. 3. Faulty coolant temperature sensor: The coolant temperature sensor is crucial for the ECU to determine engine operating conditions. If the engine starts at -10°C, the ECU may inject fuel based on a 20°C condition, resulting in insufficient fuel quantity and consequent shaking.
I've been driving my Magotan for several years and have encountered the issue of engine shaking and stalling during cold starts in the morning a few times. There are several main reasons for this. When the weather is cold, the engine temperature is low, and the viscosity of the engine oil and transmission fluid is high, leading to poor lubrication and increased internal friction. The fuel injection system also underperforms, resulting in poor fuel atomization during cold starts and uneven combustion due to a lean air-fuel mixture. Worn-out spark plugs or incorrect gaps can cause unstable ignition, and a stuck idle control valve makes things worse by failing to adjust the engine speed properly. Excessive carbon buildup in the intake manifold can obstruct airflow, affecting air intake. Additionally, insufficient battery voltage during startup can lead to sluggish cranking and stalling. To prevent this, it's advisable to park in a warmer place during cold weather, avoid pressing the accelerator immediately upon startup to let the engine warm up, and schedule regular maintenance to check these components proactively.
My Magotan always shakes violently and then stalls on winter mornings, and I suspect it's mostly a fuel issue. After long periods of parking, the fuel pressure in the fuel line is insufficient, and the fuel injectors may be clogged or spray unevenly, especially when using cheap fuel, which makes the problem more likely. A dirty throttle body blocks airflow, causing an imbalance in the air-fuel mixture and resulting in severe shaking. Faulty ignition coils or spark plugs can cause delayed ignition, and if the RPM doesn't rise, the engine stalls. Additionally, a malfunctioning coolant temperature sensor can mislead the ECU into reducing fuel injection, worsening the shaking. A simple solution is to lightly press the accelerator when starting to maintain RPM, check if the fuel filter has been replaced on time, and regularly replace the air filter to prevent dust buildup from affecting airflow. Preheating for a few minutes before a cold start can alleviate this issue and ensure driving safety.
As a car enthusiast who has disassembled vehicles for research, the root cause of the Volkswagen Magotan's cold start stalling lies in poor electronic system control. When the engine is cold, the ECU relies on sensor data. Inaccurate coolant temperature sensors or aged oxygen sensors can calculate incorrect fuel injection amounts, leading to an imbalanced air-fuel ratio. Unstable high-pressure fuel pump pressure or air bubbles in the fuel line interrupting supply, as well as excessive spark plug gaps and poor ignition timing, all contribute to increased vibration during cold starts, RPM drops, and stalling. It is recommended to use a diagnostic scanner to check for trouble codes and replace specific components or upgrade software to optimize cold start performance.
