One Of Your Car Engine’s Worst Enemies
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The 4-stroke combustion process (intake, compression, power, and exhaust) normally occurs smoothly. The pistons, spark plugs, fuel injectors, and other components work like a well-oiled machine. Pressure builds within the combustion chamber until the air-fuel mixture contained within it is ignited by the spark plug. That’s what propels your vehicle forward. When you hear a knocking sound as you accelerate, especially during heavy load, that means there is something wrong with your engine. This occurrence is called spark knock. And it can lead to expensive damage.
In this article, I’ll explain what is happening inside your engine to produce the knocking or pinging sound. I’ll also provide a few hints regarding what might be the root cause of the problem.
The Truth About Spark Knock?
The knocking sound is due to the fuel within your vehicle’s combustion chamber detonating. Rather than burning cleanly, it explodes under load, over and over. This occurs due to erratic build up of heat and pressure inside the chamber. It is not being controlled properly, and the excess heat and pressure is igniting the gas.
You might not immediately notice a change in the performance or output of your car engine. However, over a period of time, the spark knock can cause problems such as cracked rod bearings, broken rings, and head gasket problems. Each of these problems can be expensive to repair.
Reasons Knocking Can Happen
So, why does detonation happen? It can occur when your car’s exhaust gas recirculation (EGR) system malfunctions. The EGR valve is tasked with opening when you’re pushing your engine under heavy load (for example, if you’re towing something up a hill). By opening, it allows excess exhaust to flow out of the combustion chamber, lowering the temperature. If the EGR fails, this process cannot happen.
Detonation can also happen if your car’s knock sensor malfunctions. This sensor is supposed to identify situations in which the fuel is igniting erratically. It then tells your car’s computer to change the ignition timing in order to compensate. A failed sensor prevents this from occurring.
With many later model cars, detonation can be the result of carbon buildup. This will occur when their is a build up of carbon inside the pistons combustion chamber. This issue is easy to resolve by having a mechanic flushing the injectors and combustion chamber to clear all carbon build up and deposits.
Low-octane gas is another common cause of detonation. Some gas station owners label their pumps with “87″ when the octane is actually lower. Try filling your tank with a premium grade fuel from a respected brand (for example, Chevron).
If you hear knocking when your engine is under heavy load, take your vehicle to an experienced mechanic as soon as possible. He’ll have the necessary equipment to test your engine and identify the root cause of the fuel detonation. If you ignore the problem, you could be setting yourself up for expensive repairs in the future.
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