Symptoms of A Bad Catalytic Converter & How To Clean It?

catalytic converter

The catalytic converter is installed with the vehicle’s exhaust system, which is necessary equipment for every vehicle. The catalytic converter reduces pollution in the exhaust gases. But sometimes the catalytic converter installed in vehicles gets damaged or clogged, due to which you see many symptoms related to the catalytic converter. In this article, you will learn in detail about the symptoms of a clogged or bad catalytic converter and the method to clean it.

What Is A Catalytic Converter

The catalytic converter is a circular or square metal box whose structure is similar to a honeycomb. Which is used in the vehicle exhaust system. The catalytic converter helps in removing toxic and polluted gases from the engine through the exhaust pipe, making it up to 90% pollution-free and silencing the rattling sound coming from the engine.

The purpose of the honeycomb form is to ensure that polluting gases pass through the exposed surface and transform hazardous substances such as carbon monoxide, nitrogen oxides, and hydrocarbons into less harmful substances such as carbon dioxide. Despite being one of the most precious commodities, platinum is commonly used as a catalyst in catalytic converters. However, palladium and rhodium are also used on occasion.

Symptoms of A Bad Catalytic Converter

Symptoms of a bad or clogged catalytic converter may include a check engine light, heavy engine sound, acceleration hesitation, poor fuel mileage, black smoke, a low pickup problem, a catalytic converter faded golden color, an engine misfire, or a knocking sound.

Let’s take a detailed look at the symptoms of a clogged catalytic converter so you don’t get confused when it’s faulty.

1. Heaviness Engine Sound

A catalytic converter is attached to the exhaust system of every vehicle and performs a variety of functions. The catalytic converter in vehicles makes the firing sound from the engine quiet and mild. But if the catalytic converter gets damaged or the mechanism parts inside it burst, then the sound coming out of the engine of the vehicle starts coming with thick and heaviness. This can be a common symptom of catalytic converter failure.

2. Check Engine Light

Various types of electronic sensors work in vehicles. if the sensor attached to any of the parts malfunctions or is unable to function. So the check engine warning light often gets lit in the cluster meter of the vehicle.

Similarly, the sensor in the catalytic converter can light a warning light after sensing the fault of the catalytic converter, which could be a sign of a bad catalytic converter, which can be diagnosed with the help of a digital scanner. The scanner will display a P0420 fault code if the catalytic converter is faulty.

3. Acceleration Hesitation

When all other components, such as spark plugs, filters, sensors, etc., are working properly but you notice a delay at high speeds or a loss of power when driving up hills, there may be a catalytic converter problem. Many times, mechanics will confuse a bad catalytic converter with other parts, such as a bad oxygen sensor or another sensor.

To increase the car’s RPM from 2000 to 2500, keep your hand near the end of the exhaust pipe while pressing the accelerator pedal, and check the catalytic converter. If your exhaust output is insufficient, you may have a blocked catalytic converter. If you can, compare the flow to a comparable car. The car whose engine is working properly Thus, acceleration delay can also be a major symptom of a bad catalytic converter.

4. Poor Fuel Mileage

Fuel mileage is seen as a core aspect of every vehicle. When your vehicle’s engine and all its related parts are working properly, then your vehicle will consume fuel properly and at the same time, the engine will deliver performance in the best way. But if your vehicle suddenly starts consuming more fuel, this can be a major sign that the catalytic converter is bad or clogged. Because when the exhaust catalytic converter of your vehicle gets damaged or clogged.

So the exhaust will not be able to exhaust the smoke properly, due to which the engine of the vehicle may be forced to consume more fuel. However, the high fuel consumption of the vehicle depends on many other factors as well. Your vehicle may need to be diagnosed by an expert mechanic to identify this fuel consumption problem. Poor fuel mileage can also be a major sign and symptom of a bad catalytic converter.

5. Dark Black Smoke

Every vehicle’s exhaust emits different types of gases from the engine, which pass through the catalytic converter. But sometimes, due to the failure or clogging of the catalytic converter, the carbon emitted from the smoke starts to accumulate in the catalytic converter.

After some time, the black carbon in the catalytic converter comes out of the exhaust pipe during acceleration. which looks like dark black smoke. If dark black smoke starts appearing from the exhaust pipe of a vehicle. So this could be a common symptom of a catalytic converter failure. However, there can be many other reasons for black smoke coming from the exhaust. which will need to be diagnosed. Therefore, get this problem diagnosed by an expert mechanic of a vehicle.

6. Low Pickup Issue

A good performance pickup of the engine of any vehicle is a sign of a correct and fit engine. But if there is a decrease in the pickup performance of the vehicle’s engine, this can also be the main symptom of a bad or clogged catalytic converter. Because the sensor on the catalytic converter sends a signal to the ECU unit of the vehicle. based on which the ECU sends the fuel mixture to the combustion chamber. and prepares the fuel firing order.

If the sensor on the catalytic converter is unable to send the signal to the ECU, the engine’s fuel and current firing order timing process may be faulty, due to which the pickup performance of the vehicle’s engine may decrease.

But there can be many other reasons for the low pickup of the engine, which may need to be diagnosed. Therefore, in the case of poor pickup performance, get the vehicle diagnosed by an expert mechanic and get the fault code scanned with a digital scanner.

7. Catalytic Converter Faded Gold Color

Often, the catalytic converter in vehicles is made of metal. on which nickel or aluminium hypersilver colouring is done. But sometimes catalytic converters get blocked by clogs or malfunctions, which causes problems in the exhaust of various types of hot gases coming out of the engine and how the exhaust from the engine is unable to exit completely through the exhaust pipe.

Being against the catalytic converter causes the catalytic converter to overheat from the hot gases coming out of the engine. Due to which the color of the housing of the catalytic converter can be light brown or golden on overheating. A slight golden or brown color due to overheating due to a catalytic converter failure or blockage can be a major symptom.

8. Engine Starting Problem

If the vehicle’s catalytic converter is over-blocked. So starting a cold engine may cause more problems. Because when the engine is cold, the gases coming out of the combustion chamber have more pressure. And due to the blockage of the catalytic converter, these gases are not completely exhausted from the exhaust, so firing in the combustion chamber disrupts the mixture.

Hence, an engine starting problem can also be the reason for the catalytic converter getting blocked. But engine-starting problems can also happen for many other reasons. which can be diagnosed by an expert mechanic. so that the engine-starting problem can be detected accurately.

9. Engine Misfires

Sometimes the engine can misfire when the vehicle’s catalytic converter is heavily blocked. And the engine of a moving vehicle can jerk. There can be other reasons for the engine to misfire. But these symptoms can be seen even when the catalytic converter is blocked. Therefore, in the event of an engine misfire, the vehicle should be diagnosed. so that the problem of misfiring in the engine can be detected accurately.

10. Tinkling Sound

When the engine of the vehicle is started. So the catalytic converter can make the sound of something chirping or something ringing. This can be caused by the breakage or loosening of components inside the catalytic converter and makes the exhaust sound coming out of the engine heavy, due to which a loud and loud sound comes from the exhaust when the engine of the vehicle is started. This can also be a symptom of a catalytic converter failure or breakdown.

How To Clean Catalytic Converter?

Cleaning a catalytic converter can be a tricky task for the inexperienced, as it is a critical emissions control component of the vehicle. So cleaning it is not a simple DIY task. When any problem occurs with the catalytic converter, its proper maintenance or replacement is the best solution.

But if you want to clean it, you can follow this process step by step.

  • First of all, open the catalytic converter using adequate tools and disconnect it from the exhaust system.
  • Next, prepare a cleaner or soap solution in a bucket and soak the catalytic converter in it overnight, which will help dissolve the debris accumulated inside it.
  • Next, insert a clean water pressure drain into one end of the catalytic converter and turn on the water.
  • Keep the water running until clear water replaces the soot on the other side of the catalytic converter.
  • After cleaning it, dry it thoroughly and reinstall.
  • If the problem persists after cleaning, you should consider replacing the catalytic converter.

Avoid using fuel additives: There are various fuel additives available on the market that claim to clean the catalytic converter. However, their effectiveness and solutions are not long-term. Therefore, it is advisable to consult a professional before using them.


Q. What could be bad inside the catalytic converter?

Catalytic converters can often wear out over time, and they may need to be changed from time to time if they are bad. Some vehicles have an explanation of the service schedule in the owner’s manual. That the catalytic converter can be replaced when and after how many miles it runs. Typically, excess carbon from the car can damage the honeycomb of the catalytic converter.

Q. What is the life of a catalytic converter?

Catalytic converters installed in vehicles can typically run up to 100000 miles. If the engine does not have any kind of fault, for example, the engine does not produce excess carbon or the engine does not overheat for any reason.

Q. How do you fix a catalytic converter without replacing it?

If the catalytic converter fails, there may be no other option but to replace the catalytic converter, if the catalytic converter is blocked, it can be cleaned.

Share If You Like

Leave a Comment

error: Content is protected !!