Questions and Answers

Converter Removal Q. Greetings Vincent, As a matter of curiosity, what is the effect if the catalytic converter is removed and replaced with a muffler of straight pipe and oxygen sensor is refitted. Will the engine, OBD, performance and consumption vary?

A. A lot depends on the year of the car. Generally the first thing that would happen is the emissions would increase. If the O2 sensor was located after the converter, this will change the air/fuel mixture. If it was located before the converter, there wouldn't be much of a change. In later years OBD-II monitored converter operation with two O2 sensors and removing it would set a DTC and cause the MIL to light. You might notice an increase in performance due to the reduction of back pressure and there will be a change in fuel consumption.

The most dangerous consequence is if you get caught removing it, you could be fined up to $10,000.00 and win an extended vacation at a federal institution.

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