What Is the Knocking Sound I Hear Coming From My Engine?

The knocking sound that you hear coming from your engine could be caused by faulty detonation. When everything is working as it should be, the spark plugs detonate the air and fuel in each cylinder one time. There are problems that can cause the air and fuel to detonate more than once. When this happens, you hear a knocking sound coming from your engine. The other reason why your engine might knock is if the rod bearings are worn, and United Auto Care will talk more about that below.

Bad Sensor

Let’s start by talking about the things that cause detonation knock, however. It is so important that your engine does not knock that it has a knock sensor. If this sensor detects detonation knock, it notifies the main computer chip so it can adjust the air and fuel in the combustion chamber. If the knock sensor has gone bad, the main computer chip will not make any necessary adjustments and your engine might knock.

Bad Timing

Another thing that causes detonation knock is bad timing. This can happen if your spark plugs are worn and not firing properly. A faulty main computer chip can also cause the spark plugs to fire improperly. Either way, your engine will misfire and you will hear knocks as a result of the multiple detonations in the cylinders. Replacing the spark plugs or the main computer chip generally resolves the problem.

Lean Mixture

A lean fuel mixture in the combustion chamber is one that is heavy with air. Unfortunately, there isn’t enough fuel in each cylinder to fire quickly and easily. Consequently, you will end up with multiple detonations in each cylinder when there is a lean fuel mixture in the combustion chamber.

Low Octane

Your vehicle might also suffer from detonation knocking if you put the wrong fuel in the engine. For example, if you drive a high-performance automobile, the engine needs fuel that has an octane rating of 91. If you put gasoline in the tank that has an octane rating of 87 or 89, you will end up with multiple detonations in the cylinders and that annoying knocking sound coming from the engine.

Worn Bearings

Finally, as we mentioned above, if the rod bearings wear out, the rods will bang the pistons against the cylinders. This knocking sound is serious because the pistons can damage the cylinder walls. Unfortunately, you may need to replace the cylinder block, and this is an extensive repair.

Call United Auto Care in Flowery Branch, GA, today if your car, truck, or utility vehicle’s engine knocks all the time. We will find the problem and fix it.

Photo by Nixxphotography from Getty Images via Canva Pro

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