Can A Faulty Catalytic Converter Cause More Than A Failed Emissions Test?

Your car's catalytic converter is a key part of its emissions system. A faulty one will typically raise an error code and cause you to fail state emission or smog tests, in addition to triggering an ugly warning light on your dash. Of course, catalytic converter replacements are relatively expensive, leading many drivers to defer this repair for as long as possible.

Unfortunately, a failing catalytic converter is more than just a bureaucratic hassle. Even if you don't need to pass state emissions in the near term, there are several reasons why you shouldn't put off replacing a failing cat.

Why Do Catalytic Converters Affect Performance?

Contrary to common belief, you don't necessarily want your exhaust to flow as freely as possible. Manufacturers design their engines around a certain expected amount of backpressure, ultimately balancing the benefits of a freer flower exhaust with improved engine efficiency, throttle response, and torque.

Every part of your car's exhaust system contributes to this careful balance, including your catalytic converter. Catalytic converters typically fail due to age or damage from unburnt fuel entering the exhaust system, often due to other underlying issues. As the internal structure of the catalytic converter breaks down, it creates an additional restriction in the system.

This additional restriction throws off the careful balance your car's manufacturer created, increasing backpressure in your exhaust system and potentially leading to numerous negative effects. The further the catalytic converter degrades, the more it will potentially impact your vehicle's performance and fuel efficiency.

What Happens When Your Catalytic Converter Fails?

A strong sulfur smell is a symptom most people associate with a failed catalytic converter, but this odor is only the tip of the iceberg. Since your catalytic converter no longer filters sulfur dioxide, you'll usually smell a strong odor of rotten eggs near or behind your car. Any drivers unlucky enough to be behind you while you accelerate will almost certainly know something is wrong.

However, your restricted catalytic converter will also rob your engine of performance by restricting the exhaust flow. You may feel your car is unusually sluggish or notice particularly severe problems when the engine operates under load, such as when climbing a hill. You'll almost certainly notice a sharp drop-off in your vehicle's fuel economy as well.

In a worst-case scenario, the hot exhaust gases can cause your engine to run hotter than usual or even overheat. If other parts of your cooling system are weak or failing, a failing catalytic converter can overstress these components. Because overheating can cause so much damage to your engine, it's critical to deal with catalytic converter problems sooner rather than later.

For more information, visit an auto repair shop near you.