Auto Repair

Why Is My Bentley’s Engine Knocking All the Time?

If you are lucky enough to drive a Bentley, it’s crucial that you take care of it. You want to get the most miles out of this luxurious automobile that you can, and Lucas Auto Care can help you with preventative maintenance and repairs. If you’ve noticed that your Bentley’s engine is knocking, there could be a problem with the fuel that you are putting in the tank or the engine itself. Let’s talk more about this below.

Low-Octane Fuel

Most Bentley models require premium fuel in order to operate efficiently. In other words, if you put gasoline with an octane rating of 87 in a tank that requires an octane rating of 91, your engine is going to knock. This is because the lower octane fuel does not fire as quickly. Consequently, you end up with multiple detonations in the Bentley’s cylinders that cause the knocking sound.

Air-Heavy Fuel Mixture

If there is a problem with your Bentley’s oxygen or mass airflow sensor, fuel delivery, or vacuum hoses, you may end up with a lean fuel mixture in the combustion chamber. When this happens, there is not enough fuel in each cylinder for it to fire quickly and one time only. Rather you get the same multiple detonations that you get with low-octane fuel that make the engine knocking sound.

Poor Engine Timing

Poor timing will also make your Bentley’s engine knock. In other words, the spark plugs are not firing in the proper sequence and they may be firing multiple times instead of just once. This can cause a knocking sound. The reason why the spark plugs are acting up could be because they need to be replaced or the main computer chip, the engine control unit, is not firing them correctly.

Dead Knock Sensor

Your Bentley is equipped with a knock sensor that detects engine knocking sounds. Once it picks up on the sound, it sends an error code to the engine control unit. The engine control unit will adjust the mixture in the combustion chamber in an effort to decrease the engine knocks. A dead knock sensor will cause the engine to knock because it won’t report the problem.

Rod Bearing Wear

Finally, we hope that your engine isn’t knocking because of worn rod bearings. This can be an extensive and expensive repair. The rod bearings move the rods up and down so they can move the pistons. If the bearings are worn, the pistons may vibrate and crash against the cylinder walls. This is the knocking sound that you hear.

Call Lucas Auto Care in Cypress, TX, today if your Bentley or other European automobile has a knocking engine. We can find the problem and repair it.

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