Catalytic Converter Failure Symptoms

A catalytic converter failure is not only harmful to the environment, but it can rob your car of power and fuel efficiency.

When Good Catalytic Converters Go Bad

The catalytic converter in your car is passive. That is, it has no moving parts and works by creating a chemical reaction as exhaust gases pass over the surface of the unit. Catalytic converter failure is always a sign of another problem in your vehicle. Signs of catalytic converter failure include:

• No MPGs. A classic sign of a bad catalytic converter is a sudden, significant drop in fuel efficiency. Your engine has to work harder when it has trouble breathing, and that will eat into your gas mileage.
• That mushy feeling. A catalytic converter problem often shows itself in a loss of accelerating power or as a rough idle or stalling. A plugged converter limits the amount of air getting to the engine, which effects the power the engine is able to generate.
• Smell that smell. If your exhaust smells like sulfur or rotten eggs, it could be a sign that the air/fuel mixture is too rich. The unburned fuel in the exhaust is accumulating on the surfaces of the catalytic converter and cutting off airflow in your car's exhaust system.
• Watch the smoke. Contaminants in the exhaust gasses can foul the surfaces of your catalytic converter, reducing its efficiency. Blue smoke from your exhaust is a sign that burned oil is present. White smoke signals the presence of silicon, which comes from an engine coolant leak.
• Do not pass go. Don't take it personally if your car fails an emissions test-often performed during vehicle inspection-but do take it as a sign that your catalytic converter is fouled and needs to be replaced.