There are several reasons automakers are making a push toward electric vehicles.
The principal one is to reduce emissions, which is the number of gases and particles exiting the tailpipe. However, until the internal combustion engine is completely phased out, we will have to rely on catalytic converters to achieve this goal.
What is a catalytic converter? It is an emissions control device located near the exhaust manifold that reduces the toxicity of what comes out of the tailpipe. If yours is faulty, it will no longer be able to do this effectively, meaning your car likely will not pass a smog test.
Thankfully, in this guide, we will cover everything you need to comprehend about catalytic converters.
We will first take a thorough look at what it is and how it operates. Then, we’ll examine a few of the primary signs that suggest yours is failing (or has already failed).
Lastly, we will examine what causes a catalytic converter to fail and how much it costs to fix or replace one.
Let’s begin with the basics!
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What Is A Catalytic Converter, And What Does It Even Do?
Gasoline is made up of hydrocarbons, which is an organic compound consisting of hydrogen and carbon. In a perfect world, igniting all of these (including oxygen) would produce a stable combination of carbon dioxide and water.
However, because of the heat inside the engine, the reaction isn’t perfect.
Instead, it generates molecules that don’t naturally exist. As a consequence, carbon monoxide is produced, a poisonous substance that depletes the ozone layer. Moreover, if any of the hydrocarbons don’t combust, they are also released into the ambient air.
Here’s where a catalytic converter comes in, which was originally patented back in 1950 by Eugene Houdry, a French automotive engineer.
How does it function?
The components inside act as a catalyst to help transform these dangerous substances to something less harmful. Hence the name: catalytic converter.
What’s inside a catalytic converter? First, there’s ceramic, which doesn’t interact with anything but gets extremely hot, allowing the reactions to occur.
Did you know that thieves often target catalytic converters? Why? Well, these converters have some precious metals, such as platinum, palladium, and rhodium. As a result, they are quite costly.
Platinum and rhodium remove oxygen from the nitrogen atoms, causing the harmless nitrogen to exit the exhaust.
Then, platinum and palladium use the remaining oxygen molecules by combining them with carbon monoxide to create CO2. Not only that, but they’ll oxidize any surplus hydrocarbons as well as they pass through.
How does your engine optimize these reactions? It’s controlled via the electronic control module (ECM), which gets its information from two separate oxygen sensors. One is positioned before the catalytic converter and one after.
Now that you have a more accurate idea of what a catalytic converter is and how it works. Let’s look at a few of the primary symptoms you might experience that suggest yours is failing.
What Are The Signs Of A Faulty Catalytic Converter?
Decrease In Fuel Economy
Your ECM takes data from the various sensors inside the engine to optimize the air/fuel mixture inside the combustion chambers.
As we mentioned earlier, there are two sensors on a catalytic converter, one before it and one after. If there’s a blockage inside, the ECM will compensate by injecting additional fuel, therefore reducing your fuel efficiency.
The Exhaust Smells Like Rotten Eggs
If you’re in your car and suddenly notice the scent of rotting eggs, don’t blame the other passengers just yet, because it may be your catalytic converter.
Why? Because gasoline contains a small amount of sulfur, which gets converted to hydrogen sulfide during the combustion process.
If the catalytic converter is operating as designed, it will then convert this sulfide into odorless sulfur dioxide.
If it isn’t, the hydrogen sulfide will exit the tailpipe before conversion, which is what produces the awful odor.
Your Car Failed Its Emissions Test
Most states require that your vehicle passes an emissions test to ensure it’s not putting out excessive amounts of pollutants. Certification lasts for 1-3 years in most areas and usually costs between $30-$90.
A vehicle that is not certified is marked unsuitable to be driven, indicating that if you get stopped, you’ll likely receive a penalty. Not only that, but if you proceed to renew your registration on a car that is unable or hasn’t succeeded, they won’t allow you to do so.
If you get the unfortunate news that your vehicle has not passed the smog test, there is a substantial likelihood that there is an issue with your vehicle’s catalytic converter.
The Check Engine Light Appears
If you’re like most people, you have a love/hate relationship with your problematic engine light.
Sure, it’s always disturbing when it shows up, and it usually means you’ll need to spend some money to take care of it. But if you inquire about the cause as soon as it lights up, you’ll likely prevent whatever it is from becoming more severe.
The ECM takes the data from the two catalytic converter oxygen sensors. If they detect that the exhaust gases aren’t catalyzing properly, the ECM will illuminate the check engine light.
Having an engine light appear doesn’t specifically mean it’s the catalytic converter. But you can take your car to a repair shop or use an OBDII scanner yourself to be certain.
Engine Performance Drops
One of the most common signs that indicate a problem with your catalytic converter is weak acceleration.
This usually occurs when it becomes too hot for an extended period, which causes the internal components to melt.
This can lead to a blockage inside that restricts the exhaust flow. In this case, you’ll need to have it repaired/replaced. Though, it’s also possible that there’s a buildup of carbon, which can be easily removed using a specific cleaner.
What Causes A Catalytic Converter To Fail?
The positive news is that most catalytic converters will last between 10-15 years, primarily because there are no interior moving parts.
However, just because they have a prolonged lifespan does not mean the surrounding components do. If they aren’t functioning correctly, it can reduce how long your catalytic converter lasts.
A few potential causes that may cause it to fail include:
- Antifreeze in the exhaust
- Bad spark plugs
- Faulty oxygen sensor
- Unburnt fuel in the exhaust
- Oil in the exhaust
How Much Does It Cost To Repair/Replace A Catalytic Converter?
The expense of repairing a catalytic converter varies broadly, but typically falls between $1,000 and $2,500.
What affects the cost you pay?
- The make and model of your car
- Diagnostic fees and additional issues
- The number of hours it takes to replace
- The quality of the replacement part
For the make and model, it all comes down to rarity and complexity. A catalytic converter replacement for a 92 Civic is far less expensive than on something like a BMW X3 or a Saab 9-3.
One way to keep costs low is to purchase a generic-fit catalytic converter rather than one engineered specifically for your model.
However, keep in mind that these are never as effective as an OEM product and may void a manufacturer warranty if it is still in effect.
As for repairing a catalytic converter, it is generally wise to replace it and track down what caused it to fail in the first place.
Sometimes it is possible to clean a clogged one, just do not forget to determine why it occurred.
