Catalytic Converter - Failure Types & Symptoms

Catalytic Converter Failure Symptoms

A catalytic converter failure is the most rare issue that heads up in front of you. This might result due to problem or malfunction occurring in the emission system in front of the converter. It is very important to determine what caused the converter to fail so that the problem can be fixed and to prevent a recurrence of the failure.

Here are Some Major Reasons Responsible For Catalytic Converter Failure :

• Physical damage : Generally happens by off road practice and running over road debris, which in return causes collisions and other impacts. These faults are easy to detect. This type of damage can break up the ceramic substrate or cause restriction that changes the flow characteristics of the converter or impacts the efficiency of the catalyst.

• Thermal Shock : This occurs when a fully heated converter comes in contact with snow or ice. This leads to sudden contraction of the converter housing, which can cause cracks and disintegration of the ceramic substrate. Symptoms include a “rattling” sound when the converter is tapped with a fist or mallet.

• Plugged Substrate : It is also known as contaminated substrate, this can be the result of an overly rich air/fuel mixture, radiator sealant, and oil or antifreeze entering the exhaust flow. The resultant carbon deposits restrict the operation and ultimately the flow characteristics of the converter by coating the unit’s reactive surface. This degrades the converter’s ability to perform its chemical conversion process, leading to potentially illegal levels of HC, CO, and NOx.

• Thermal Failure : This type of failure occurs when excessive raw fuel comes into contact with the catalyst, and “burns” in the converter. The high quantity of fuel generates temperatures in excess which is over the capacity of the converter, and causes meltdown of the ceramic monolith. This reaction also leads to a significant loss of engine power. Potential causes of thermal failure include, misfire, malfunctioning oxygen sensor, fuel delivery issue, improper choke setting/operation, and ECU malfunction.