What Are the Things That Cause an Engine to Knock?

Oxford Automotive advises that it’s important to know the things that can make a car, truck, or utility vehicle’s engine knock because one of these things can actually damage the engine. Let’s talk about the common reasons why engines knock below. If your automobile’s engine is knocking all the time, bring your vehicle to our shop right away.

87 or 89 Octane Fuel

Generally, knocking sounds are caused by incorrect detonation in the engine’s cylinders. Instead of just one detonation, unusual conditions in the cylinders cause multiple detonations. These multiple detonations are what make the knocking sound. One such condition is fuel that has an octane rating that is too low for your engine, such as 87 octane in a high-performance engine.

Lean Fuel Mixture

If the fuel mixture in the combustion chamber has too much air in it, this, too, can cause more than one firing in each cylinder. Things that create a lean fuel mixture include a clogged fuel filter, clogged fuel injectors, clogged fuel lines, a faulty mass airflow sensor, a faulty oxygen sensor, and an engine vacuum leak. A malfunctioning fuel pump can also create a lean fuel mixture.

Constant Misfiring

Another thing that will cause multiple firings in each cylinder is faulty spark plugs or a malfunctioning engine control unit. The spark plugs should only fire once in each cylinder per cycle. If they are worn, they may fire more than one time. You may also have a faulty engine control unit that is causing the spark plugs to misfire. This poor engine timing will make the engine knock.

Faulty Knock Sensor

There is a knock sensor in the engine to make sure that any knocking sounds are addressed as soon as possible. This sensor communicates with the engine control unit if it detects knocking in the engine. This gives the engine control unit the opportunity to correct a problem such as too much air in the combustion chamber. If the knock sensor is bad, it will not send an alert to the engine control unit.

Worn Rod Bearings

As we said above, one cause of engine not can damage your vehicle’s engine. Specifically, worn rod bearings will cause the rods to move the pistons up and down inside the cylinder unevenly. When this happens, the pistons will make violent contact with the cylinder walls and damage them.

Oxford Automotive in Oxford, PA, can determine the reason why your engine is knocking and fix the problem. Call us today.

Photo by Mike Bird from Pexels via Canva Pro

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