What are the reasons for the shaking of Passat B5 during cold start?
2 Answers
The reasons for the shaking of Passat B5 during cold start are: 1. Excessive carbon deposits inside the engine, leading to a lean mixture during cold start, causing shaking; 2. Mechanical failures such as ignition coils, spark plugs, or fuel injectors; 3. Low oil pressure or cylinder pressure, resulting in insufficient power; 4. Poor fuel quality; 5. Damaged or dirty idle control valve; 6. Leakage in the intake manifold; 7. Damaged engine mounts or rubber pads; 8. Oxidized or low-grade engine oil. The Passat B5 is the fifth-generation model of the Passat brand sedan from Volkswagen AG in Germany, with body dimensions of: length 4608mm, width 1743mm, height 1465mm, and a wheelbase of 2610mm.
Having driven the Passat B5 for so many years, cold start shaking is quite common. In most cases, it's due to aging of the ignition system, such as spark plugs that have been used for too long without replacement, where the gap becomes larger leading to unstable ignition. Also, excessive carbon deposits on the valves, clogging the intake passages, can prevent air from entering during cold starts, affecting the combustion of the air-fuel mixture. The fuel system is another issue; insufficient fuel supply from the fuel pump or clogged fuel injectors can starve the engine. Additionally, high oil viscosity and inadequate lubrication at low temperatures can increase friction and shaking. Preventive measures include regular maintenance, replacing spark plugs every two years or 20,000 kilometers, and cleaning the throttle body to avoid carbon buildup. In cold weather, warm up the car for half a minute before starting and avoid stepping on the accelerator too quickly. Engine shaking might seem like a minor issue, but ignoring it can lead to more serious faults, such as valve damage, which would incur higher repair costs.
