What Causes Engine Shaking During Cold Start in New Cars?
2 Answers
New car engine shaking during cold start may be caused by: 1. Insufficient engine temperature: Poor fuel atomization at low temperatures requires higher ignition energy. After prolonged use, the spark plug gap tends to widen, reducing ignition energy and affecting power output, resulting in vibration. 2. Inaccurate air-fuel mixture ratio: Occurs in both open-loop and closed-loop control systems. 3. Excessive engine carbon deposits: Carbon buildup can obstruct the idle air control valve or exceed the adjustable range of the idle channel. 4. Faulty ignition coils or spark plugs: Causing misfire in one cylinder which leads to vibration. 5. Malfunctioning coolant temperature sensor: Displays hot engine temperature signal during cold start, preventing ECU from receiving signal to provide richer mixture, thus causing vibration.
Cold start shaking in new cars is quite common, with various possible causes. When the engine starts cold, the low oil temperature and high viscosity of the lubricant can hinder piston ring movement, leading to unbalanced operation and resulting in shaking. This is primarily caused by incomplete fuel combustion. Common factors include clogged fuel injectors, impurities in gasoline affecting atomization quality, and ignition system issues such as aging spark plugs or incorrect gap settings, which disrupt ignition timing. The engine control module may also respond sluggishly in cold conditions, contributing to the problem. While new cars typically don’t experience this, abnormal fuel pump pressure or faulty sensors (e.g., temperature or mass airflow sensors) can worsen the shaking. It’s advisable to first check fuel quality—avoid low-grade gasoline, try switching gas stations, or use higher-octane fuel. Highway driving can help clear carbon deposits. If the shaking persists, seek professional diagnosis promptly to prevent engine damage. After all, new cars are still under warranty—don’t take it lightly.
