engine knocking sound

Engine Knocking Sound: Causes & Fixes


August 10, 2022

Do you hear an engine knocking sound when you accelerate your vehicle?

Don’t be concerned if this is the case; many others have experienced it as well!

Low octane gasoline or faulty spark plugs are commonly to blame for engine knocking.

It may also be caused by unclean injectors or engine wear in rarer circumstances.

In most situations, it’s simple to repair yourself or have it fixed by a mechanic, but you can also use aftermarket solutions to address the problem.

This is a typical annoyance that many drivers face.

We’ll go over the causes of this knocking noise and how to fix it in this post.

How Does Engine Combustion Function?

The combustion reaction starts when the spark plug fires, generating a spark that ignites the air-fuel mixture in the cylinders.

The flame then propagates swiftly from the spark plug to the rest of the fuel.

The pistons are pushed up and down by the heat from the burning fuel and air, which powers the crankshaft.

The crankshaft transforms the reciprocating motion of the pistons into rotational movement, which powers all of the car’s functions.

The combustion of the air-fuel mixture produces a lot of pressure within the cylinders.

This pressure drives the piston downward, turning the crankshaft and propelling the car forward or backward.

How Does The Engine Convert Heat Into Motion?

The burning air-fuel mixture heats the pistons, causing them to move up and down.

As a result of this movement, the crankshaft rotates.

The reciprocating motion of the pistons is transformed into rotational motion by the crankshaft, which drives all of the automobile’s systems.

How Does The Engine Knocking Sound?

When the mixture detonates too soon, it can create a knocking sound.

This happens because the pressure waves from premature combustion collide with each other and produce noise.

Engine knocking can also be caused by deposits on the piston or valves.

When these deposits catch fire, they may produce a similar sound.

Can The Oil Change Solve Engine Knocking?

Engine knocking can be caused by a variety of things, but an oil change isn’t likely to fix the problem.

In fact, if you hear an engine knocking, it’s suggested that you have your car looked at by a mechanic so they may identify the cause and recommend a solution.

red chevrolet camaro on road

However, if you only want to change your oil for whatever reason, there are a few things to keep in mind.

First and foremost, make sure you use the correct type of oil for your vehicle.

This information may be found in your owner’s manual.

Also, be sure to follow the suggested maintenance intervals when changing your oil.

Old oil can damage engine components over time and cause knocking.

While an oil change may not cure your engine knocking issue, it is still a smart idea to keep your automobile well-oiled and operating smoothly.

For more information on engine knocking and how to repair it, please contact a professional in your area.

What Causes The Engine Knocking When Accelerating?

Knock is caused by an air-fuel mixture that isn’t burning properly.

The uneven combustion of the fuel and air combination generates this knocking sound.

Engine knocking can be attributed to a number of things, including:

  • Low octane gasoline
  • Defective spark plugs
  • Dirty or clogged injectors
  • Worn out engine parts

Low Octane Gasoline Bad For Your Car

Although low-octane gasoline is not bad for your automobile, it can cause the engine to malfunction.

If you use low-octane petrol in a car that needs premium gas, it will result in declining performance and possibly damage the car engine.

There are certain various aftermarket solutions on the market that can assist with knocking reduction.

Gasoline Octane Booster is one such product.

Symptoms Of The Clogged Or Dirty Injectors

The following symptoms can indicate that your car’s injectors are clogged or dirty:

  • Poor fuel economy
  • Reduced engine power
  • Engine knocking
  • Hesitation when accelerating

It’s critical to have your injectors cleaned on a regular basis in order to avoid these difficulties.

Dirty or clogged injectors can cause significant engine damage, so it’s always better to be cautious than sorry.

If you’re not sure whether your injectors need cleaning, come in for a tune-up and ask your mechanic for advice.

How To Clean Dirty Injectors

blue bmw m 3 parked on parking lot during daytime

The best method to clean dirty injectors is with an ultrasonic cleaner.

This sort of cleanser makes use of high-frequency sound waves to clean the injectors.

You may also clean the injectors using a carburetor or brake cleaner.

Before applying any of these chemicals, be sure to check the manufacturer’s instructions for safety precautions.

Symptoms Of Defective Plugs

A faulty spark plug might lead to a variety of issues in your automobile.

Some typical symptoms include:

  • Difficulty starting the car: A faulty spark plug might prevent your car from starting. This may be caused by a lack of spark or an inability of the plugs to fire properly.
  • Poor performance: It’s possible that your car won’t run as smoothly as it should be because of a bad spark plug. You might notice hesitation, stalling, or poor acceleration.
  • Increased emissions: If your car’s spark plugs are bad, it will produce more emissions than usual. This might lead to environmental and public health hazards.
  • Decreased fuel economy: A faulty spark plug can cause your automobile to consume more gasoline than necessary. This will result in increased fuel costs and fewer miles per gallon.
  • Rough running engine: When a spark plug is not operating efficiently, it can cause the engine to run erratically. You may hear knocking, pinging, or rumbling sounds.

If you’re experiencing any of these symptoms, it is critical that your car’s spark plugs be examined.

If you’re searching for a new spark plug, make sure it’s compatible with your car’s manufacturer and model.

There are many various sorts of spark plugs on the market, so it is critical to get the correct one.

If you’re unsure whether a certain plug is appropriate for your car, consult with your mechanic.

It’s a difficult process to replace your car’s spark plugs.

If you’re not comfortable doing it yourself, you may want to get a friend or family member to help you.

They’ll be able to replace the plugs quickly and easily, saving you time and effort.

How To Test For Defective Plugs

The simplest method to check for faulty spark plugs is with a spark plug tester.

This sort of tester, which connects to the plug wires and measures the voltage generated when they fire, may be used as a substitute for a voltmeter.

You can also inspect for signs of wear or damage while removing and inspecting bad spark plugs.

Symptoms Of Worn Out Engine Parts

The following symptoms could occur if you have an automobile with worn-out engine components:

  • Engine knocking
  • Poor fuel economy
  • Reduced engine power
  • Rough idle

Symptoms of malfunctioning engine parts might include a knocking sound, difficulty starting the car, or a drop in fuel efficiency.

If you are experiencing any of these issues, it is essential that your vehicle be inspected by a mechanic as soon as possible.

Engine parts that have been used for an extended period of time may significantly reduce the lifespan of your automobile and can also be dangerous.

Ignoring engine symptoms of wear and tear can lead to more significant issues in the future.

How To Test For Worn Out Engine Parts

A compression tester is an ideal instrument for detecting worn-out engine components.

This type of tester, which attaches to the spark plug wires and assesses compression produced when the plugs fire, is one of several types of testers that may be used.

You can also check for signs of wear or damage by removing and inspecting bad spark plugs.

How To Solve The Engine Knocking?

If your car’s engine is making a knocking sound when you accelerate, there are a few things you can try to address the problem.

  • Use higher octane gasoline, if available. This will aid in the fuel’s uniform burning and minimize knocking.
  • Clean or replace the spark plugs. Dirty or faulty spark plugs may cause the air-fuel mixture to ignite erratically.
  • Replace your injectors if they’re clogged or unclean. Injectors that are clogged or dirty can cause the air-fuel mixture to be delivered unevenly to the cylinders.
  • Check for faulty engine components. Engine parts that are worn out can create an air-fuel mixture that ignites erratically.

When accelerating your automobile, you should notice a reduction or elimination of the knocking sound if you follow these recommendations.

If the problem persists, you may need to have your car inspected by a specialist.

Can Additives Solve The Engine Knocking?

There are a variety of additives available that promise to eliminate knocking in engines.

However, there is no scientific evidence to back up these claims.

Octane gasoline keeps your injectors and spark plugs clean are the best ways to prevent engine knocking.


Jeffrey Bryce is an experienced motorcycle rider with years of experience caring for motorcycles. His natural fondness for motorcycles have made him come up with LetsGoForARide.com, which is dedicated to answering and teaching you how to care for your bike with the care it requires. LetsGoForARide is the one of his important lifework in reaching out to communities of motorcycle enthusiasts on how to take care of their bike and choosing the correct spare part.