6 Causes Behind the Failed Catalytic Converter in BMW The catalytic converter does not have any moving parts, so it seems to be the most durable and long-lasting component in your BMW. In modern cars, the catalytic converter is developed with advanced technology, but still, it fails due to several reasons. It’s always important to fix the failed catalytic converter by recognizing the causes behind it. If you neglect the cause and don't fix it on time, then the problem will likely destroy the converter entirely and need replacement as well. The below-listed points are responsible for the replacement of installed catalytic converters in your BMW.
Exhaust system covered with unburnt fuel The fuel is burnt up in the combustion chamber for powering your BMW. But, when the unburnt fuel enters the exhaust system through the combustion chamber can ignite. When it reaches the catalytic converter during ignition can overheat the converter beyond its normal operational limit and cause melting down issues. Due to other reasons also the catalytic converter can overheat such as: ● ● ● ● ●
Bad oxygen sensor Improper fuel mixture Damaged spark plugs Failed fuel injector Damaged check valve
Faulty or bad spark plugs Generally, the spark plugs force the unburnt fuel to enter into the exhaust system due to the lack of misfiring. The reason behind is, the catalytic converter gets very hot. As a result, the unburnt fuel ignite inside the converter and partially or completely melting down the ceramic catalyst.
Structural damages in a catalytic converter The catalyst honeycomb which is located in a catalytic converter is commonly made up of thinwalled, lightweight, fragile ceramic material that is wrapped in a dense and insulated mat. The mat of the catalyst honeycomb protects the converter against damages. When the potholes, cracked exhaust hangers, or the speed bumps impact underneath the car it will strike the catalytic converter and fracture the catalyst.
If the honeycomb is fractured, then its small pieces rattle around and interrupt the exhaust flow. Due to the fractured honeycomb, the backpressure inside the exhaust system can increase the heat buildup and loss of power. Apart from this, other issues also responsible for replacing the catalytic converter such as: ● Metal fatigue ● Damaged oxygen sensor threads ● Corroded thermal shock
Engine tune-up The engine will need proper tune-up for its better service. But in reality, the older engines will burn more fuel due to numerous causes such as stuck rings, damaged cylinder walls, and the faulty valve. As a result, it will produce more by-products that may foul the converter. When the engine is unable to function properly, then it may damage the engine as well as the catalytic converter.
Oil enters the exhaust system If the oil enters into the exhaust system, then it will create a thick carbon and soot. Eventually, that will clog the air passages in the catalytic converter’s ceramic honeycomb catalyst. Due to these reasons, the carbon deposits interrupt the catalytic converter to remove the harmful emission in the exhaust flow. When the exhaust flow is restricted due to the clogged pores in the ceramic catalyst can increase the backpressure. If excess back pressure is created then it will damage the internal engine. These problems also arise due to the failed gaskets, damaged engine components, faulty piston rings, and faulty valve seals.
Damaged oxygen sensor If you find that the oxygen sensor of your BMW is not working properly, then make sure that it can send incorrect exhaust gases reading to the computer. The wrong reading will show improper fuel mixture conditions and fuel burning inside the converter can melt down the catalytic converter. The damaged catalytic converter will be unable to change the hydrocarbons into safe elements and make the car fail the emission test.
Conclusion
If you are rarely driving your BMW in a town with short trips and not driving it long distances regularly, then you will notice that the catalytic converter is unable to get hot enough to burn away the hydrocarbons. To prevent the clogged catalytic converter issues in your BMW, it’s always advisable to take your car for highway drive for 15 minutes or more occasionally. Through this process, the exhaust system will heat up sufficiently and burn off all the carbon deposits. Otherwise, consult with a reputed and trained technician to diagnose the failed catalytic converter of your BMW and repair it immediately.