Restricted catalytic converter

A restricted catalytic converter can slow or stop the flow of exhaust gases. This will increase the pressure in the exhaust manifold and can lead to a reduction in engine power.

Table of Contents

• 1. Symptoms
  • 1.1 Vehicle Backfires
  • 1.2 Vehicle has a Gas Smell

Symptoms

A restriction in the catalytic converter, or any part of the exhaust system, can create a build up in pressure that can cause the exhaust gases to to reenter the combustion chamber and alter the fuel/air ratio.

Vehicle Backfires

A backfire occurs when fuel is ignited outside of the combustion chamber, specifically in the exhaust manifold. A restricted catalytic converter can build pressure in the gases leaving the combustion chamber. As the chamber tries to expel these gases, the pressure prevents them from doing so. When the engine draws more fuel and air in, the presence of exhaust gases prevents the full amount of fuel and air to enter.

As combustion occurs, some of the fuel may not be burnt, but exit the combustion chamber with the exhaust gases. The heat of the engine and exhaust gases may then ignite the fuel inside the exhaust manifold, causing a backfire.

This may also reduce the engine power as a the amount of fuel and air entering the combustion chamber is reduced.

Vehicle has a Gas Smell

The back pressure of the exhaust gases can create exhaust leaks which can create the smell of fuel inside or outside of the vehicle.