What Causes Severe Body Shaking in BMW Vehicles?
2 Answers
Analysis of the causes for severe body shaking in BMW vehicles is as follows: 1. Severe engine carbon buildup: When there is excessive carbon buildup inside the engine, the gasoline sprayed by the cold start injector will be largely absorbed by the carbon deposits, resulting in an overly lean air-fuel mixture during cold starts and making ignition difficult. Under these conditions, the vehicle will only start easily once the carbon deposits have absorbed enough gasoline to reach saturation. After starting, the gasoline adsorbed on the carbon deposits will be drawn into the combustion chamber by the engine's vacuum suction, causing the air-fuel mixture to become too rich. The fluctuating lean and rich conditions of the engine's combustible mixture lead to idle shaking after a cold start. 2. Unstable oil pressure: It is advisable to visit a 4S shop to check whether the fuel supply pressure and the intake pressure sensor are functioning normally. If the fuel pump's supply pressure is abnormal or the intake pressure sensor's readings are incorrect or malfunctioning, it can also cause body shaking.
My BMW 5 Series also had that violent shaking issue last year, turned out to be worn engine mounts. The rubber components harden and crack over time, transmitting all engine vibrations into the cabin. Another time on the highway, the steering wheel vibrated so badly it numbed my hands - tire dynamic balancing revealed several missing wheel weights on the front tires. BMW's ignition system is particularly finicky; excessive spark plug gap or aging ignition coils cause misfire vibrations, especially noticeable during cold starts. The dealership mechanic also warned me about worn driveshaft universal joints making the chassis 'dance' - and BMW parts are notoriously expensive. Pro tip: never cheap out at sketchy gas stations - low-quality fuel causes carbon buildup that makes the engine run rough.
