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7 Symptoms of A Bad Catalytic Converter

What are the symptoms of a bad catalytic converter?

  1. Dark exhaust smoke
  2. Rotten egg odor
  3. Rattling noises
  4. Vehicle won’t start properly
  5. Reduced acceleration
  6. Low fuel efficiency
  7. Check engine light is on


A catalytic converter is a part of your vehicle’s exhaust system that helps filter harmful gases before it goes out of the vehicle. This component converts pollutants such as carbon monoxide, nitric oxide, and unburned gas into harmless gases. They often last the lifetime of your vehicle but because of several engine issues might need to be repaired or replaced. If you experience these bad catalytic converter symptoms, you need to order new parts soon! Keep on reading.


Dark Exhaust Smoke

The catalytic converter helps filter out the harmful particles from the gases produced by your vehicle. That’s why if it’s not working properly, you might see dark exhaust smoke coming out of your tailpipe. If this is component is severely clogged, the exhaust will build up inside. When it comes out, it’s thicker and darker than normal.

For reference, the exhaust smoke must be light or thin white. Anything other than that signals a bigger problem in your vehicle.


Rotten Egg Odor

Rotten Egg Odor

Whether or not you have dark exhaust smoke coming out of your vehicle, you must be alert for any weird smells coming out from your tailpipe. For instance, if you sniff out the scent of rotten eggs, this is a sign that you might have a catalytic converter problem.

In your vehicle’s fuel, there is a substance called sulfur that turns into hydrogen sulfide when your engine is in use. When your catalytic converter is functioning properly, it converts this substance into sulfur dioxide which is odorless. That’s why if you smell rotten eggs, you know that something is not working as it is supposed to be.


Rattling Noises

As a driver, you also need to be alert for unusual noises produced by your vehicle. For instance, if you hear a rattling sound under your car, parts of your catalytic converter might have broken apart due to extreme heat or damage. You’ll notice this when you’re starting your vehicle.

If this happens, you want to take your vehicle to a mechanic to have the damaged parts removed. If not, this can cause more problems such as blocking your muffler.


Vehicle Won’t Start Properly

Vehicle Won’t Start Properly

Speaking of starting your vehicle, a clogged catalytic converter can make it harder to do so. If your car stalls or sputters, this is because the exhaust gases can’t make it out of your tailpipe properly. This adds pressure to the engine and makes it hard to start your vehicle.

Cleaning a clogged catalytic converter is fairly easy if you go to a mechanic. But if you have severe blockage problems, your engine might not run at all. In some cases, broken parts of the converter might have caused the clog. If this happens, you need to replace it completely.


Reduced Acceleration

In relation to difficulty starting your vehicle, you might also notice poor acceleration compared to normal. If you step on the gas pedal but don’t notice a big difference, this is another red flag that you have a clogged catalytic converter. It might occur due to too much exhaust build-up.

This is because your engine needs proper exhaust to function properly. If you notice that your vehicle is becoming sluggish, it is a good idea to have the catalytic converter inspected. You might be burning extra fuel due to this too.


Low Fuel Efficiency

Low Fuel Efficiency

Speaking of fuel, when you have a clogged catalytic converter, your vehicle will burn more fuel because of the reduced airflow. This problem is worsened if you increase the pressure on your gas pedal because you’re trying to speed up. This might be the reason why you don’t have a good mileage as you used to have.

If you notice that your vehicle isn’t performing at its peak, it’s better to have it checked soon. Otherwise, you might just be wasting fuel and making the clog worse.


Check Engine Light Is On

There are numerous reasons why your check engine light is on. For instance, you might just have a faulty gas cap. But in some cases, it might indicate that you have a misfiring engine that can lead to overheating of your catalytic converter. This might also signal you that your converter is not working properly.

Because a check engine light can have many different meanings, it is handy to have a diagnostic tool on hand. You can also head to your mechanic for assistance.


Key Takeaway

Whether it’s a rotten egg smell, a darker than usual exhaust smoke, or a bit of rattling noise—your vehicle might be having a hard time due to a failing exhaust system component. If you notice these bad catalytic converter symptoms, you might need to repair or replace this part immediately! Otherwise, you might have trouble starting your car, maintaining acceleration, and more.

If you’re looking for durable and long-lasting catalytic converters, you can send a message here at Roberts!

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