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Catalytic Converter Problems

Shrinivas Kanade
It is not that on everyday you have to face problems, of one or the other sort, related to your car's catalytic converter. Are these problems inbuilt into it due to its faulty or too fragile design or are there some other external factors responsible for it? Know more about what governs the health of this mandatory environment protective device.
Poorly maintained vehicle may be one of the underlying reasons for a substandard catalytic converter. The trouble-free working of this device depends on many factors. Malfunction of any of these can cause a perfectly useful equipment to start giving you operating and financial problems. How do you spot the cause leading to malfunctioning of this car part?

Symptoms of a Bad Catalytic Converter

The catalytic converter sits between the exhaust and the engine, and cleans the exhaust gases of harmful pollutants. Its honeycombed internals, made of palladium, rhodium and platinum coated ceramic structures, can convert air pollutants such as carbon monoxide into carbon dioxide and nitrogen oxides into nitrogen and oxygen.
It also reduces harmful hydrocarbons in the unburnt fuel before releasing the emissions. The most easily observable symptom is the loud noise made by the exhaust gases leaking from a compromised shell. The cause of the damage may be an undercarriage incident such as stone bouncing off the converter.
Here is a list of symptoms you can test your converter for:
  • The impact of stones and such events may break the fragile ceramic structures inside the shell, and you may be able to hear the rattling noise it makes.
  • The engine performance may get hampered, due to lowered exhaust back pressure.
  • Lowered efficiency of engines, in terms of fuel consumption.
  • Insignificant response from the engine, in terms of acceleration, when you push the gas pedal.
  • Alerts from the oxygen sensor which monitors the performance of the device.
  • A running engine going dead on you, for no apparent reason.

Commonly Faced Converter Problems

The temperature at which this device operates is in the range of the 1,200 to 1,600 degrees Fahrenheit. Increase in its internal temperature can harm the car performance drastically or the catalytic converter itself.

Unburnt Fuel

Unburnt fuel igniting outside the combustion chamber and within the converter can cause problems. The tremendous heat (approximately 2,000 degrees Fahrenheit) generated by this incident causes the converter meltdown, which may lead to a blockage in the exhaust.
The following factors may cause unburnt fuel to leave the combustion chamber and enter the catalytic converter:
  • Incorrect fuel mixture or timing setting.
  • Faulty spark plug, fuel injector or oxygen sensor.
  • Malfunctioning of check valve or a sticking float.

Antifreeze and Oil

Chemicals such as burnt oil or antifreeze creates heavy carbon particles, which on entering the converter coats the palladium and platinum lined ceramic structures and hampers their working. These heavy particles also block the pores or holes in the converter through which the cleaned exhaust gases escape out of the converter.
This causes the heat and the exhaust gases to back up into the combustion chamber. The faulty or worn piston rings or valve seals, failed gaskets or misshapen engine parts may also lead to this problem.

Faulty Oxygen Sensor

A faulty oxygen sensor may cause the computer, which controls the engine of the vehicle, to inject more or less fuel in the combustion chamber than required.
This eventually disturbs the ideal air (i.e. oxygen) and fuel ratio in the combustion chamber and affects the efficiency of the vehicle. This ratio is required to get optimum mileage and avoid converter problems that may arise because of unburnt fuel.
The catalytic converters are necessary to prevent environmental pollution. Proper maintenance of your car will definitely help you in avoiding malfunctions of this device and using it efficiently throughout its life.
A number of states in the U.S.A. and the governments of many countries have passed strict laws regarding the harmful pollutants levels in the exhaust gases. Many of them have made regular automobile emissions testing mandatory for every vehicle.
During these testes, presence of the device in the vehicle and whether it is working properly or not, is checked. So, take care of it as soon as you detect something is wrong with it by visiting a competent car mechanic.
This will help you in saving on its replacement cost and in avoiding fines. If you need to replace it, make it your business to ensure the new device strictly adheres to the performance guidelines set by the authorities. Happy Driving!