What is a Catalytic Converter?

The Government has forced to attempt to limit potentially damaging emissions. The catalytic converter is a device located in the exhaust system which converts environmentally unwelcome gases from the exhaust into harmless Carbon Dioxide (the same as we breathe out), Nitrogen(which forms 80% of air), and water vapour in the form of steam. It does this by passing the gases through a fine honeycomb usually made of metal that is plated with other precious metals such as platinum, palladium and rhodium. It is these precious metals that initiate a chemical reaction which converts the emissions.

Main Reasons for Catalytic Converter Failure

It has been known that garages have fitted new catalytic converters without first checking the underlying reason it may be failing. At Bicester Auto Repairs we will always perform thorough testing to identify any faults and to establish whether the fault can be fixed without having to replace.

If your catalytic converter does require replacing we will advise you of what may cause the underlying reason it has failed to help prevent reoccurrence.

The main reasons a catalytic converter will fail are:

• Wrong fuel type
  If the wrong fuel is used it will block the catalytic converter
   
• Faulty oxygen sensor
  A faulty oxygen sensor will provide a too rich fuel mixture and can poison the converter
   
• Misfire
  These are usually caused by a failure in the ignition system. Fouled spark plugs, broken-down ignition leads or cracked distributor caps cause the engine to 'stutter'. Every time the misfire happens, some un-burnt petrol finds its way down the exhaust pipe. This fuel then poisons the converter.
   
• Faulty injectors
  Injectors distribute controlled amounts of fuel into the engine in response to the demands of the driver. Certain inferior brands of fuel lack detergent which over time can cause deposits to form on the injector nozzle. This prevents it from closing properly and can allow unwanted petrol to leak into the engine. This will eventually poison the converter.
   
• Failed manifold air pressure (MAP)sensor
  A failing MAP sensor can cause a rich fuel mixture which eventually can poison the converter.