Road / Structural Damage
The catalyst honeycomb inside of a catalytic converter is made up of a lightweight, thin-walled, fragile ceramic material. It is wrapped in a dense, insulation mat. This mat holds the catalyst in place and provides some protection against damage. However, broken exhaust hangers, off-road driving , potholes, speed bumps or any impacts underneath your vehicle can strike the catalytic converter causing a catalyst fracture. Once the ceramic honeycomb is fractured, the broken pieces rattle around breaking up into smaller pieces. As a result, exhaust flow is interrupted and backpressure in the exhaust system increases leading to heat buildup and loss of power. Corrosion, thermal shock, metal fatigue, stress fractures and stripped oxygen sensor threads are some other issues that may require you to need a replacement catalytic converter.
Oxygen Sensor Not Functioning Properly.
If your oxygen sensor is no functioning properly it can send incorrect readings of exhaust gasses to the vehicle’s computer. The faulty sensor readings can result in a improper (too rich or too lean) fuel mixture condition. Too rich and the catalyst can melt down from fuel burning inside the converter. Too lean and the converter will not be able to serve its purpose changing hydrocarbons into safe elements. This may cause your vehicle to fail the emissions test during the annual State Vehicle Inspection.
Short Trips
If you gennerally only take short trips around town in your vehicle and dont regularly drive long distances, your catalytic converter may not be getting hot enough to completely burn away the hydrocarbons. To prevent clogging the catalytic converter, take your vehicle for the occasional highway drive for 15 minutes or more. This will allow the exhaust to sufficiently heat up and burn off all of the deposits builtup in the catalytic converter.