How to Fix Diesel Engine Knocking

How to Fix Diesel Engine Knocking – Easy Method Explained In 2024

Suppose you are driving peacefully, then you hear a sudden and violent knock on your diesel engine out of nowhere. This is both troubling and scary for the users.  Study shows, in the year 2020, almost 75% of all citizen will use vehicles that are powered by diesel engine and face this noise issue.

Your usual diesel engine may make different kinds of noises like- rattling noise, knocking noise, ticking noise, chain meshing noise, etcetera. But to stay safe, you must identify the sinister noises and be clear about how to fix diesel engine knocking.

You initially keep in mind that the injector of your engine produces this knocking sound. This kind of abnormal combustion is harmful. Sometimes it is the beginning of other mild issues and proceeds towards the decay of your engine.

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Use of Diesel Engine

A diesel engine is still very popular among people. Generally, you can count on it in locomotives, automobiles, construction ingredients, and in many more industrial works.

Diesel engines are normally louder than petrol engines because of their difference in the compressor. Your usual diesel engine may make sounds like banging, clanging but you are unsure whether it is dangerous or normal. But it is important to recognize the harmful knocking from the engine.

What Is Diesel Engine Knocking?

When your diesel-powered vehicle’s engine makes wired husky noises, it is called Detonation or diesel engine knock. Generally, motorbikes are the victims of it. Injectors of an engine create noise. Probably they lack lubricant, or using bad fuel also makes the noise worse.

How Can You Identify a Diesel Engine Knocking?

How Can You Identify a Diesel Engine Knocking?

What you will do is use a Diesel Purge. As a recognized driver, do you know what diesel purge is? But let me explain why to use it. When you apply a purge, most of the normal noises will be disappeared.

Typical diesel engine noises come from the ignition and nailing of the engine. The lubricant of the purge will decry the hammering, and within 10 to 15 minutes, the noise will be softened. An example is Mercedes’s fuel injector noises.

If the sounds end like that, they were never harmful engine sounds, and you can be relieved. But if it leaves, the engine is in danger. Do not drive the vehicle until the sound is gone.

What Can Happen If You Ignore It?

You know, modern engines have knock detection systems, but the older ones don’t. So you must be sincere about this issue if you are an owner of an old engine.

You can wait and observe for 1 or 2 days to rectify if this noise is cured by itself or not. But you will not be sitting for long. Try to fix this issue then and then without ignoring it. If this continues to happen, your engine’s efficiency will be lost.

If the sound becomes huskier day by day, this is called the rough running of an engine. Rough running wreck the engine in the long run.

So, be concentrative when following the steps of how to fix the knocking of a diesel engine.

Why do they happen?

Why do they happen?

  • Injectors are the main culprit behind it. Probably they lack lubricant and become rough. Using bad fuel in the engine also makes the noise.
  • When a high pressure strikes the cylinder head and piston, it creates the diesel engine’s knocking.
  • Again, when a large number of air-fuel flames out at a time, it causes combustion, and this turmoil makes bang noise and knocking. The incorrect mixture of the air-fuel mainly causes the knocking sound here.
  • Uneven burn of the Gasoline inside of your engine makes a Pop shock wave. This ultimately deliberates the knocking sound

How to Fix Diesel Engine Knocking?

Fix Diesel Engine Knocking?

The main and most preferable solution is to replace the injectors with new ones.

Step 1: Make sure you have no residual pressure inside your vehicle. To check that, plug in a diagnostic tool and be assured.

Step 2 : Put on your goggles and gloves and remove the vehicle’s cover. Remove the injector pipe. Do not contaminate any of the parts.

Step 3: Remove the back linkage, remove the glow connector but do not lose the electrical connection. Now it leaves only the clamp holding of the injector. Withdraw the injector from the seat.

Step 4: Fit the newly repaired injector now. Make sure your new injector is vacuum-sealed and clean. Note down the correction code.

Step 5: Re-fit all the equipment you removed one by one. Re-fit the high-pressure fuel pipe.

Step 6: After the physical part, now comes the mental part of the work. Entering the code. Codding tallies up your vehicle with the new injector.

Step 7: Start your vehicle and go for a drive to check out the new injector you just repaired. If you experience a noiseless drive, congratulations to you. You made it!

Additional Suggestion

Additional Suggestion

  • Use the right tools and right torque while repairing.
  • New injector code must be programmed to the ECU.
  • Set them fitted with the new high-pressure pipes and filters.
  • Set new injectors as the manufacture’s recommendations.

Now, if you do not want that much costly solution, I can suggest some beneficial yet less expensive prevention.

  • Doping: Use 1% Ethyl Nitrate in the injector. It accelerates the combustion of fuel. If not ethyl nitrate, any nitrate is preferable. It decreases the suspension time noticeably. This prevents diesel knocking.
  • Increase the compression ratio: The more compression ratio a diesel engine has, the less it will make the engine knocking. It is a special quality of a diesel engine.
  • You need to increase the ratio of the compressor to get a much higher temperature. High temperature makes the ignition of the fuel more naturalistic. It also increases the pressure rise that makes the engine run smooth. A smooth engine is a noiseless engine.
  • Increase the turbulence of the Compressed air injector. It reduces the diesel knocking
  • Make sure your injector only impels a small amount of fuel while starting the engine. Rearrange your injector.
  • Raising your engine’s injection pressure promotes the atomization of fuel prevents the engine from knocking.
  • Coolant intakes air into the cylinder head and combustion chamber. Raise the heat of the coolant, and the knocking will be disappeared

If you stick to the procedure and complete the task with perfection, the knocking will be gone for life. Your engine will be soothing. You will drive safely again.

Important to Mention

  • Work in a safe and clean environment.
  • First, identity, the sound you are experiencing is harmful or normal. Unnecessary stroking can be injurious to your vehicle.
  • Be cautious while replacing the engine. Do not work barehanded. Use gloves and keep a close water source.


Final Thoughts

Final Thoughts

Engine knocking is both annoying to the mind and dangerous for life for all users. Now that you have learned how to fix diesel engine knocking, you can again have your soundless engine back.

Finally, by following the right instructions, your defective and noise-making diesel engine can be preserved timely and perfectly. So, it’s time to take action before it is too late.