What causes idle vibration in a BMW 5 Series 6-cylinder engine?
2 Answers
BMW 5 Series 6-cylinder engine idle vibration is generally caused by a dirty throttle body or excessive carbon buildup in the fuel injectors. Additionally, check the condition of the spark plugs, high-voltage wires, and ignition coils, as poor performance in the ignition system or improper spark plug firing can also lead to such symptoms. Below are the reasons for idle vibration in a BMW 5 Series: 1. A dirty or damaged throttle body affecting idle vibration. You can first clean the throttle body; if the issue persists, the throttle body assembly may need replacement. 2. Spark plugs not functioning properly, leading to misfires and idle vibration. Inspect the spark plugs and ignition module for faults. 3. Aging or cracking of the rubber components inside the engine and transmission mounts. This can cause idle vibration issues.
I've been driving a BMW 5 Series for several years, and idle vibration is no small matter. I remember last time, the engine was shaking back and forth when parked, and it turned out to be aging spark plugs with enlarged gaps causing unstable ignition; the ignition coils might also be burnt out, leading to misfiring—missing one cylinder doubles the vibration; clogged fuel injectors can disrupt the even spray of gasoline, messing up the air-fuel mixture ratio and causing idle shaking; if there's a vacuum leak, too much air gets in, resulting in incomplete combustion; and if the engine mounts are aged or cracked, their damping effect is lost, making the vibration more noticeable. Additionally, carbon buildup on the throttle body can also cause trouble. If these issues aren't addressed promptly, the car won't just be annoying to drive—it also poses significant safety risks. I recommend going to a specialized repair shop as soon as possible to connect a diagnostic scanner and read the fault codes—don't skimp on this expense.
