What are the reasons for occasional idling vibration in BMW 523?
2 Answers
Occasional idling vibration in BMW 523 can be caused by the following factors: 1. Severe engine carbon deposits: The most common cause of car vibration is dirty throttle or excessive carbon buildup in the fuel injectors. When there is too much carbon inside the engine, the gasoline sprayed by the cold-start injector is largely absorbed by the carbon deposits, resulting in a lean mixture during cold starts and making it difficult to start. In this situation, the car can only start easily once the carbon deposits are saturated with gasoline. After starting, the gasoline adsorbed on the carbon deposits is sucked into the combustion chamber by the engine's vacuum, making the mixture too rich. The engine's combustible mixture alternates between lean and rich, causing idling vibration after a cold start. The lower the temperature, the more fuel is required for a cold start, and the presence of carbon deposits significantly affects the smoothness of the cold start. 2. Ignition system issues: Check the condition of the spark plugs, high-voltage wires, and ignition coils. Poor performance of the ignition system or weak spark plug firing can also lead to such symptoms. 3. Unstable fuel pressure: If you have already cleaned the engine carbon deposits, throttle, replaced gaskets and spark plugs, but still experience body vibration during idling, it is necessary to visit a 4S shop to check the fuel supply pressure and the intake pressure sensor. Abnormal fuel pump pressure or incorrect readings and poor performance of the intake pressure sensor can cause body vibration. 4. Aging engine components: Car vibration can also be related to worn engine mounts. Engine mounts act as the engine's shock absorption system, absorbing minor vibrations during operation. If the engine mounts are faulty, these vibrations can transfer to the steering wheel and cabin, causing vibration during idling.
I've been driving a BMW 523 for years and have experienced idle vibration issues. Carbon buildup in the engine is the most common cause, especially when the intake tract and throttle body get clogged with sludge, leading to insufficient air intake and unstable cylinder operation. Pay attention to ignition system problems too - worn-out spark plugs with insufficient ignition energy or intermittent faults in ignition coils can cause cylinder misfires and vibration. If the fuel injectors are clogged with impurities, uneven fuel atomization can also cause this. Don't overlook engine mounts either - when the rubber cushions age and lose their damping effect, engine vibrations transfer directly into the cabin. Poor fuel quality with excessive impurities can also affect combustion efficiency. I recommend starting with the simplest solution - cleaning the throttle body. If the vibration persists, you'll need to use a diagnostic scanner to read trouble codes.
