My BMW Shaking While Idling, Is it supposed to do that? Introduction Do your BMW shake while idling? It makes the car less comfortable for passengers when the car idle and can make a person in the car tensed. If your car shakes vigorously while idling, then know that something in the car is wrong. Such shaking which makes uncomfortable is unusual. I’m gonna tell you what causes such shaking while idling and how to get rid of such condition.
What is idling? And why shaking matters? Idling is such a condition, where engine is on, but the vehicle is not in motion. We can say a car is idling when it is stopped due to red light in traffic, waiting for someone after starting the engine. Idling occurs due to the rotation of crankshaft due to the activities of engine. Idling is measured in rpm. Generally cars idle with a speed 600-900rpm and motorcycles with 1000-1500rpm. Two types of idling generally occur in vehicles, smooth idling and rough idling. Smooth idling is natural and indicates that there is no issue in ignition of fuel and running of engine. Slight vibration with a smooth sound of engine occurs. But in case of rough idling, vibration or the shaking becomes vigorous. Rough idling causes energy loss in engine and making it less fuel efficient. Rough idling can cause damage to the engine easily than normal smooth idling.
What causes my car to vibrate while idling? Spark plugs and its wiring If the spark plugs or its wiring are bad, then it couldn’t burn the fuel-air mixture completely, then it will cause rough idling of the car, and rough idling is a condition where cars vibrate mostly. So when the spark plugs are worn out or carbon and oil deposited over its tip, then power created from ignition will be highly reduced.
Air filters Air filter traps the dust, debris particles in it and allow clean air to pass to the engine to make air-fuel mixture. It air filter gets clogged with dirt particles then it will affect the permeability of the filter and will minimize the air flow. As the air flow is decreased, there will be less amount of air in air fuel mixture, which will lead to rough idling.
Oxygen sensor If oxygen sensors are bad and begin to malfunction, then it will lead to formation of air-fuel mixture with wrong ratio of air and fuel. The oxygen sensor finds out the amount of oxygen in the exhaust gas and gives the information to the control unit. If the sensor is bad, then it would give wrong information on amount of oxygen in the exhaust gas. The oxygen sensors become bad due to long term usage, carbon deposits over it, etc.
Fuel injectors The function of fuel injector is to provide optimal amount of fuel to the engine cylinders for combustion. Fuel injectors gets carbon deposits over it due to its work over time. These components get clogged by carbon due to continuous deposits of carbon. This restricts the amount of fuel flow through it. As proper amount of fuel is not dispensed and right time, failure of perfect combustion occurs. This causes rough idle.
Motor mount There are some motor mounts which holds the engine with engine compartment and absorbs the vibration of engine during idling. When any one of the motor mounts is broken, then the impact of shaking of engine becomes more on other and can lead to damage of other motor mounts. When shaking happens while your car is in neutral, then know that the culprit for such shaking is bad motor mounts.