BMW Oxygen Sensor Symptoms

by Jonathan Lister
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The BMW has become a status symbol in the United States. The German automobile is produced in a variety of makes and models, all with luxury and precision in mind. It is this precision that makes its working parts all the more susceptible to wear and tear. A faulty oxygen sensor, a relatively small component of the fuel delivery system, can have a large impact on fuel economy and engine performance in the BMW. An observant driver will take heed of its symptoms and address the issue before the malfunction becomes a full replacement.

Poor Fuel Economy

BMW engines are fuel-injected and therefore depend greatly on the ratio of fuel to air being pushed by the fuel pump into the engine block. A malfunctioning oxygen sensor can reduce the amount of air flow, along with fuel, resulting in too much fuel entering the engine during combustion. This obviously uses up gasoline a lot faster than normal, and the driver may find he doesn't get as far on a full tank of gas as he used to. An altered air-to-fuel mixture will also produce increased emissions through excessive or insufficient combustion within the BMW's engine.

Rough Idling

Ignition and acceleration systems in a BMW have advanced electronic components making engine timing critical to maintaining a properly running automobile. A faulty oxygen sensor can throw off piston timing resulting in a rough idle and reduced efficiency. The driver will experience rattling or some degree of shuddering from underneath the hood radiating through the steering wheel. A rough idle will more than likely lead to engine hesitation as the vehicle attempts to accelerate. This hesitation is a result of the damaged oxygen sensor incorrectly reading the air-to-fuel mixture flowing into the engine resulting in inadequate fuel supply.

Engine Misfire/Backfire

Nothing is quite as embarrassing as the sound of a precision automobile backfiring in traffic. A malfunctioning oxygen sensor can cause such a problem for the motorist due to a lean supply of fuel being pushed into the engine. Too little or too much fuel alters the way an engine explodes (causes combustion) with the gasoline, resulting in unpredictable acceleration and performance.. When this occurs in the intake manifold, it will produce the thunderous bang that is the hallmark of an engine backfire.

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