Symptoms of a Bad Catalytic Converter

Symptoms of a bad catalytic converter can be easy to spot. Your car's catalytic converter is the part of the exhaust system that turns dangerous hydrocarbons and carbon monoxide into less harmful water vapor and carbon dioxide. It's easy to detect a bad catalytic converter's symptoms and a failed unit should be replaced promptly.

When Your Catalytic Converter Cries For Help

A catalytic converter has an easy job when it's in good condition: exhaust gases pass through the unit and are converted by a chemical reaction between the gas components and the surface of the unit. A faulty catalytic converter, however, robs your car of performance and dumps pollutants into the atmosphere. Here's how to tell the difference:

• I feel a headwind. If your vehicle has little accelerating power, or it feels like you're driving into resistance, this could be a sign that the catalytic converter is plugged. A plugged converter is typically a sign that your vehicle may have fouled sparkplugs or a burned exhaust valve. These problems allow unburned fuel into the exhaust system, where it accumulates in the catalytic converter.
• Where did all the gas go? A sudden and noticeable drop in fuel efficiency may also be a sign that the catalytic converter has become plugged.
• What's that smell? A sulfur or rotten egg smell coming from your exhaust is a sign of a too-rich fuel mixture-the extras fuel in the exhaust is plugging the catalytic converter.
• Epic fail. If your car fails an emissions test (commonly given during vehicle inspection), this is sign that the catalytic converter is fouled. Fouling occurs when a contaminant coats the inner surfaces of the unit, blocking the chemical conversion from occurring. The color of exhaust smoke can be used to tell which contaminant is fouling the converter. Blue smoke indicates the presence of phosphorus, which comes from burnt motor oil. White smoke indicates the presence of silicon, which comes from burnt engine coolant.