The difference between detonation and rod knocking is that the former is a problem with the detonation in the combustion chamber and the latter means the pistons are clanking against the cylinder walls. We are going to talk more about the causes of detonation knock and rod knock below. Either way, Accurate Auto can repair the underlying cause of your knocking engine.
Detonation Knock
Let’s have a class in automobile engine performance or just a moment. In order to understand detonation knock, you need to understand how your engine works. Your engine is a combustion engine; therefore, it needs both air and fuel to work as an accelerant. The engine control module, the main computer chip, determines how much air and fuel is needed in the combustion chamber for proper ignition. Specifically, the air and fuel are placed into each cylinder.
Once the cylinders are filled with the correct amount of air and fuel, the spark plugs generate a spark to ignite it. You have one spark plug for each cylinder. If the conditions in each cylinder are perfect, the air and fuel will ignite once to create a tiny fireball. If the conditions are imperfect, the air and fuel may ignite multiple times and create several tiny fireballs. When these fireballs explode, they make the knocking sound that you hear coming from your engine.
There are several things that can affect how many fireballs you end up within each cylinder. They are
- Low-octane fuel that does not fire quickly enough for a high-performance engine
- Bad engine timing that causes the spark plugs to generate multiple sparks out of order
- A lean fuel mixture that is too heavy in air and does not fire quickly enough
- A faulty knock sensor that cannot alert the engine control module of engine knock
The latter is a sensor that is designed to detect knocking sounds coming from problems with your engine’s detonation. It notifies the engine control module of the problem and the module corrects the air and fuel balance to prevent the engine from knocking. If the sensor has gone bad, the engine control module will be unaware that the engine is knocking.
Rod Knock
If your engine is knocking because of the rods or the rod bearings, you have a serious engine problem. Once engine combustion begins, the pistons move up and down inside the cylinders. They are moved up and down by rods that are connected to bearings to keep the movement straight. If the rods or rod bearings are going bad, the pistons will not move cleanly up and down inside the cylinder walls. Rather, they will bang against the cylinder walls and damage them.
Accurate Auto is the best auto service shop in Beaverton, OR. We are also the best auto service shop in Lake Oswego, Hillsboro, and Tigard, OR. Call the shop that is closest to you today if your engine is knocking. We will get to the bottom of the annoying sound.
