What Causes Vehicle Body Shaking When Cold
3 Answers
Cold start shaking is fundamentally caused by poor combustion in the cylinders. Here are the key explanations regarding engine shaking:1. Low ignition energy at low engine temperatures: Insufficient engine temperature leads to inadequate fuel and lubricant temperatures, requiring more fuel injection during cold starts to meet power demands. Larger spark plug gaps result in weaker ignition energy.2. Improper air-fuel mixture ratio: Inaccurate fuel-air mixture occurs in both open-loop and closed-loop control systems. In closed-loop vehicles, the oxygen sensor requires a minimum operating temperature of 370°C. During cold starts, the exhaust pipe temperature doesn't reach this threshold, preventing the oxygen sensor from functioning.
As a beginner in the automotive world, I was particularly troubled by the issue of engine shaking during cold starts with my new car—it felt like the vehicle was about to fall apart. Later, I learned there are several common causes: irregular ignition due to worn spark plugs or carbon buildup, issues with the ignition system such as loose ignition coils or wiring harnesses; unstable fuel supply, like clogged fuel injectors or insufficient fuel pump pressure; faulty air flow sensors or temperature sensors can cause the ECU (Engine Control Unit) to misjudge, leading to idle fluctuations; excessive carbon deposits inside the engine can also cause vibrations during cold starts due to high oil viscosity and incomplete combustion. Additionally, for manual transmission cars, clutch-related components might contribute to the problem. It's advisable not to ignore this—have a reliable repair shop check the spark plugs, wiring, and carbon buildup. Using high-quality engine oil during regular maintenance can help alleviate the issue.
I've been driving for over twenty years and often encounter the issue of engine shaking when cold, which is quite bothersome. This problem usually stems from ignition system failures; worn-out spark plugs or severe carbon buildup can cause unstable ignition, and if the ignition coil is faulty, the engine will shake violently. Fuel system issues like insufficient fuel pump pressure or clogged fuel injectors are also common culprits. Additionally, carbon deposits accumulating in the throttle body or cylinders can cause rough idling during cold starts. My car used to shake badly, and upon inspection, it turned out to be a loose ignition wire connection—replacing it made a huge difference. I recommend first checking the spark plugs or giving the throttle body a simple clean. If the issue persists frequently, a professional diagnosis is advisable.
