Toyota Corolla Exhaust Smell – Is My Catalytic Converter Clogged?

A strong exhaust smell inside the cabin and poor acceleration could indeed point to a clogged catalytic converter, though there are a few other possible causes to consider as well. To diagnose a clogged catalytic converter without removing it, here are a few steps you can take:

Check for a decrease in performance: If your car struggles to accelerate, especially when driving at higher speeds o r during heavy acceleration, it may be due to a clogged converter restricting the flow of exhaust gases. This could lead to a decrease in power and performance.

Look for a rotten egg smell: A common sign of a failing o r clogged catalytic converter is a sulfur o r rotten egg smell coming from the exhaust. If youre noticing this, it could confirm the issue.

Use a temperature check: Using an infrared thermometer, you can check the temperature before and after the catalytic converter. If the converter is clogged, the temperature at the exit end of the converter after the exhaust gases pass through will be lower than the temperature before the converter. A difference of over 100°F can indicate a blockage.

Perform a backpressure test: This test measures the amount of exhaust backpressure and can help detect a blockage in the exhaust system. A mechanic can perform this test, and if theres too much backpressure, it could point to a clogged converter.

Examine the exhaust gases: A mechanic can use a gas analyzer to check for abnormal levels of oxygen o r carbon monoxide in the exhaust, which can indicate improper exhaust flow due to a clogged converter.

Fixes Before Replacing the Converter:

Cleaning the Catalytic Converter: There are some catalytic converter cleaning products available that may help remove minor clogs o r debris from the converter, but they’re generally less effective for severe issues. Using a fuel system cleaner can also help clean the system, though it may not completely clear a significant clog.
Inspecting the Exhaust System: Make sure the exhaust system isn’t leaking o r obstructed elsewhere, as this can sometimes mimic catalytic converter issues.

If these methods don’t resolve the problem and you continue to experience poor acceleration o r strong exhaust smells, it may be necessary to replace the catalytic converter.