What causes a BMW 5 Series to shake upon ignition and then stall automatically?
2 Answers
For a BMW 5 Series that shakes upon ignition and then stalls automatically, there could be numerous potential causes, such as issues in the fuel system, ignition system, or intake system. Problems in any part of these three systems can lead to this phenomenon. Additionally, poor fuel quality can also cause the BMW 5 Series to stall immediately after ignition. Extended Information: 1. When the engine temperature is low, fuel is less likely to evaporate or vaporize. If there is severe carbon buildup in the fuel lines, intake passages, or other areas, these carbon deposits will first absorb some fuel vapor. This can easily result in an overly lean air-fuel mixture entering the cylinder for combustion, leading to unstable idling, stalling immediately after ignition, and other symptoms. If you attempt ignition several times, the carbon deposits will become saturated with fuel vapor, allowing the air-fuel mixture entering the cylinder to meet the standard, and the engine can then start. 2. A faulty fuel pump may suddenly seize or experience other issues, causing it to underperform or stop, resulting in insufficient fuel supply and stalling. Low fuel system pressure, such as weak fuel pump pressure, fuel line leaks, insufficient electrical current, or a damaged fuel pressure regulator, can also lead to inadequate fuel supply. Clogged or leaking fuel injectors can cause poor fuel atomization, resulting in insufficient fuel supply and stalling.
I've been driving a BMW 5 Series for over a decade, and the issue of engine shaking during startup followed by stalling is quite common. It's mostly caused by ignition system problems, such as worn spark plugs or leaking ignition coils. When spark plugs reach the end of their lifespan, they're prone to misfiring which causes shaking, while unstable power supply from ignition coils can make the engine stall instantly. Another possible cause is insufficient fuel pump pressure - delayed fuel supply during cold starts can trigger this symptom, and a clogged air filter restricting airflow can also contribute. I recommend checking these wear-prone components first. BMW engines are precision machines, so replacing spark plugs periodically as preventive maintenance is wise - don't wait until a high-speed stall causes an accident.
