Last Updated on
Many people have wanted to know what causes spark knock. Everyone has had experience with this before. You are out for a walk and on the road when you hear the loud knocking of someone else’s engine. Ratting and pinging might be other noises as well. It truly is not a pleasant sound. Of course, you never want this to happen to you, but if it does, you need to know what causes it.
At its most basic of form, a spark knock is a combustion, but there is a lot more than meets the eye. This type of combustion happens when there are too much heat and compression. Even though combustion is a controlled experience in a vehicle, a spark knock is not a natural thing. The combustion happens outside of its normal chamber. With added cylinder pressure, you get the annoying noises. Of course, if this does not get fixed, a head gasket problem is emminent, along with ring damage.
Engine Spark Knock: What Causes Spark Knock?
Nevertheless, why does this abnormal combustion happen? Well, let us hop into the most common reasons why. The Faulty EGR Valve is a great place to start.
Faulty EGR Valve
When it works normally, an EGR (exhaust gas recirculation) valve help release exhaust gases. With the help of rerouting technology, emissions are reduced and the temperature during combustion is lessened as well.
As acceleration happens in a vehicle, the EGR stays open to allow the exhaust to be rerouted. When the EGR does not work appropriately, the gas cannot be rerouted. The temperature will continue to increase during combustion. Knocking sounds in the engine will continue to happen moving forward as well.
Carbon deposits are another reason why the EGR will not open either. If you imagine this is the reason for the spark knock, the EGR will need to be replaced. However, if things with the EGR are fine, then it is time to move onto the Knock Sensor.
The Knock Sensor Going Bad
With the modernized vehicles in the 21st Century, they are all supplied with knock sensors in the engine. However, if you have a vehicle older than the 1990s, then you should move onto the next possible spark knock issue. But, let us continue if you have a knock sensor.
This mechanism can adjust on the fly with ignition timing. With this in mind, the detonation process for combustion can be fixed. But, if the knock sensor does not communicate anymore to your vehicle’s computer, a spark knock will start to happen.
The computer will start to slow down the timing ignition during the combustion process. In turn, your power will be reduced in the engine as well. Even though this technology is around to save your engine from the worst damage, you will start to hear pinging noises when you accelerate the engine. To this point, there are some tests you can do to see if the knock is coming from the sensor. Have a mechanic do this to make it easy on you. If it passes, carbon buildup is next.
A Buildup of Carbon
The older your vehicle is, the worse chance carbon will buildup in your engine. Higher miles will not do you any favors either. Where carbon likes to build up is on piston tops. Combustion chambers also can get carbon accumulation, too.
Primarily, you will have a buildup of carbon happen when a car does not warm-up the way it was made to. This also can happen when people only drive a few minutes at a time regularly. To help with the problem of carbon, there are fuel additives that clean the chamber while it is in use. Other cleaners include ones to help with the carbon on the pistons. You can do this on your own, but a mechanic can certainly help with the process as well.
The Wrong Gas
You might not always think about the gas you put in your vehicle, but you should make it more of a priority in your life. You truly do not want to have low octane gas ruining the party going on in your engine.
Low octane gas can be the culprit for the knocking and pinging that can be so annoying. By following the car manufacturer’s guidance, you should not run into this problem. But, you should be diligent to figure out the right fuel for your vehicle.
Some people think low octane gas is better on your vehicle, but this could not be further from the truth. With low-quality issues, the fule will start to buildup cylinder pressure and the temperatures in the chamber used for combustion. Unfortunately, you will hear more and more knocks due to the combustion that has gone haywire.
Fortunately for you, this is one of the easiest fixes when it comes to a spark knock. Just change your fule up to a high-octane gas to get rid of the problem. However, if this does still not fix the issue, then your exhaust system may be gaining unwanted pressure.
An Exhausted Exhaust System
When you have increased pressure going to your exhaust system, you can imagine the temperatures rising and the combustion pressure increasing. As the gases leave out the tailpipe, they can start to get clogged. This is when you hear the unpleasant sounds coming out of the tailpipe itself.
When the gas gets to the tailpipe, it cannot work its way back to the intake manifold. This is why you get a huge burst out of the tailpipe. A good muffler will not help you hear. The combustion chamber will have an explosion and it will have to go somewhere. Inspection and evaluation are key here by a trained professional or if you believe you can handle the severity of the problem.
An Extreme Compression Ratio
This ratio usually happens in engines that are rebuilt, so if that is not you, move onto something else. However, if this could be the problem for you, this has everything to do with oversized cylinders. They can cause extra static compression. In turn, the volume in the combustion chamber reduces, yet the static increase. Insert more explosions here!
With these upped compression rations, the engine receives more power, but pinging and kncoking can be a result as well. If you do have low octane fuel, as stated earlier than this could make the problem worse. Even an engine that is turbocharged or supercharged can have spark knocks.
Bad Fuel Mixers
Low octane gas is not the only fuel that can cause spark knows. A lean fuel mixture can do it as well. The right mixture can do wonders for your vehicle, but the wrong one can cause heat to buildup and the combustion chamber to start to buckle at the seams. It is things like grimy fuel injectors and vacuum leaks that do most of the damage here. Lastly, a bad MAF sensor or limited pressurized fuel is no good either. Look into these components to come up with a solution.
Spark knocks are about the worst sounds you can hear in the automotive world. However, if you can pinpoint the issue, you will be well on your way to figuring out how to fix it. When everything is said and done, then you can enjoy your vehicle for all it is worth.
Because every human who owns a car on planet Earth wants it to work, so they can use it to their advantage. Those advantages can be adventures, memories, and so much more. Feel confident knowing you know how to identify a spark knock. This way, you will continue to build confidence whenever you have a vehicle issue that needs assistance. Happy trails to you and the ones you ride with!