What Causes BMW 5 Series to Shake When Cold?
2 Answers
BMW 5 Series shaking when cold may be caused by faults in components such as ignition coils, spark plugs, or throttle bodies. Possible issues include carbon buildup on spark plugs, dirt accumulation on the throttle body, or damage to ignition coils. Below is an analysis of potential causes related to car shaking: 1. Excessive Carbon Buildup: Excessive carbon deposits can lead to low fuel pressure, resulting in insufficient fuel supply and power loss. It is recommended to clean the fuel injectors and check fuel pressure. Another possibility is poor ignition causing incomplete combustion and noticeable fuel wastage, which can be resolved by replacing spark plugs. 2. Insufficient Cylinder Pressure: This commonly manifests as cylinder misfire and shaking, accompanied by power loss. Cylinder pressure testing is required. Finally, visually inspect whether the wheel balancing weights are missing or if there is any obvious wheel hub deformation.
I've been driving for over a decade and encountered many cold start vibration issues. It's actually quite common for luxury cars like the BMW 5 Series to experience cold start shaking. The most frequent cause is engine carbon buildup, especially after driving 70,000-80,000 kilometers. We veteran drivers all know that when carbon deposits partially clog the fuel injectors during cold starts, uneven fuel injection makes the engine shake like it's having spasms. Aged spark plugs are another major culprit - I've seen cases where replacing them solved the vibration completely. Don't underestimate worn engine mounts either - when those rubber parts crack, engine vibrations transmit directly into the cabin. Once I even encountered fuel line blockage from bad gasoline - the fuel pump made buzzing noises during cold starts. I recommend owners check these areas first; if that doesn't work, professional carbon cleaning is needed.
