What Causes Detonation Engine Knock?

A detonation engine knock means that you have multiple detonations in each cylinder. There is air and fuel in each cylinder that is ignited by the spark plugs. There is only supposed to be one detonation, but the circumstances that we will list below can cause multiple detonations to go off. When this happens, this is the engine knock that you hear. Stringer Auto Repair advises that it isn’t healthy for your engine to knock. You should bring your vehicle to our shop right away.

Bad Knock Sensor

Your engine has a sensor that is designed to detect when there is a detonation knock. Generally, adjustments to the air and fuel in the combustion chamber can stop the detonation knock. The sensor alerts the main computer chip, the engine control unit, that the engine is experiencing detonation problems. The engine control unit adjusts the air and fuel in the combustion chamber to stop the knocking. If the knock sensor is bad, the engine control unit will not be warned of detonation problems.

Air-Heavy Mixture

Air and fuel combust together to create detonation in the cylinders. This combustion is what starts your automobile and keeps it running. If there is too much air and not enough fuel in each cylinder, you will end up with multiple detonations, i.e., a knocking engine. Things that can cause an air-heavy mixture include a clogged fuel filter, clogged fuel injectors, and problems with the oxygen sensor.

Low-Octane Fuel

Another problem that causes detonation engine knock is fuel that has octane lower than what your engine requires. Higher octane fuel burns more quickly. Lower octane fuel does not burn fast enough in high-performance engines, and, as a consequence, it will detonate multiple times. You need a higher octane that burns quickly and only detonates once to prevent low-octane fuel knocking.

Poor Engine Timing

Another issue with your engine’s detonation can lie with the spark plugs. If they are worn and not firing correctly, the timing inside each cylinder will be off. Consequently, you may end up with more than one detonation in each cylinder that causes an engine knock.

Bonus Cause

Finally, there is also a cause of engine knock that has nothing to do with detonation. This cause is worn rod bearings. The pistons move up and down in the cylinders via the rods. If the bearings attached to the rods are loose, the pistons will rattle inside the cylinders. This is the knocking sound you hear.

Stringer Auto Repair in Johnstown, OH, is a full-service auto shop that can determine why your engine is knocking and fix the problem. Call us today for an appointment.

Photo by Andregric from Getty Images via Canva Pro

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