categories
find your car
or search VRM
Help Page - Catalytic Converters
These help pages are designed as a guide only
A catalytic converter is a device located in the exhaust system of all cars and most light duty trucks after 1990. It chemically converts pollutants like carbon monoxide, hydrocarbons and nitrous oxides into harmless substances like carbon dioxide, nitrogen and water vapour. A converter uses an inside structure called a substrate that is plated with precious metals such as platinum, palladium and rhodium. These elements cause the chemical change. Catalytic converters are subject to a number of regulations within the EU. For most countries in the EU only a catalytic converter which is Type Approved can legally be fitted, in the United Kingdom only cars registered from March 2001 must have a typeapproved cat fitted.

Things to watch out for when ordering.
Catalytic converters from most car manufacturers change quite regularly and as well as make, model and year the body style and engine code are often very important. All of our catlytic converters have photos or technical diagrams which represent the item being listed. If you are in any doubt whatsoever about the correct fitment for your car them contact us before ordering.
Frequently Asked Questions
Q: HOW DO I KNOW IF MY CONVERTER IS WORKING?
A: A catalytic converter will noticeably cause the vehicle to run poorly only in extreme cases where the converter melts down and plugs up the exhaust system. Generally, the only indication you will have that your car's converter is not working is when you fail an emission test.
Q: WHAT WOULD CAUSE MY CAR'S CONVERTER TO FAIL?
A: Many things can cause a converter to fail. Fuels containing lead are the leading cause of converters failing due to contamination, a misfiring spark plug or bad wire can cause a converter to overheat and melt down. A defective oxygen sensor, stuck choke, worn carburettor or any defective sensor or engine part can also cause converter failure. Proper repairs must be made to ensure that the replacement converter will not also fail.
Q: HOW LONG IS THE REPLACEMENT CONVERTER'S WARRANTY?
A: Aftermarket converters are warranted for 25,000 miles or 1 year for the substrate and 50,000 miles or 5 years for the converter shell.
Q: WHAT DO I DO WITH THE WARRANTY CARD?
A: The warranty card should be filled out by the installer and posted to the address on the front of the card. The warranty statement and receipt should be retained in the event of converter failure.
Q: WHAT IF I DON'T FIND A REPLACEMENT CONVERTER LISTED IN THE CATALOGUE FOR MY CAR?
A: If you cannot find a replacement converter in the catalogue European Exhaust & Catalyst Ltd will recondition your converter and warranty for the same period as our new converters. However, new parts are becoming available every day, so please check.
Common Problems
FUEL
Unleaded fuel must be used in vehicles with a catalytic converter. Using leaded fuel will cause the converter to become plugged and inoperative. Also some gas additives can damage a converter. Always check the instruction label of any additive added to your fuel system to be sure that it is converter safe!
OXYGEN SENSORS
This sensor sends information to the ECU (Electronic Control Unit) to maintain proper air/fuel mixture. It is located either in the exhaust manifold pipe or catalytic converter. As an oxygen sensor operates, it checks to see if oxygen is present in the system. If no oxygen is detected in the system, this would indicate a rich mixture, the oxygen sensor will read about 900mV (millivolts). When excessive amounts of oxygen are present, the sensor voltage will read about 100mV Rich mixtures mean high readings, lean mixtures mean low readings. Please note the exhaust temperature must be at least 600 degrees fahrenheit for the sensor to operate, and the measurements should only be taken with a multimeter that has a 10 meg ohm impedance rating. Failure to follow this rule may cause you to replace the vehicle's ECU. A properly functioning sensor will oscillate between 900mV and 100mV every few seconds. You can measure this with your multimeter. If the reading does not oscillate or stays fixed, the sensor is defective. Also note that silicone from either antifreeze or RTV (silicone) sealant, can clog an oxygen sensor and the mixture rich and in time will ruin the combustion chamber the sensor should be replaced. When using a silicone sealer, make sure it is oxygen sensor safe.
CARBURETTOR SYSTEMS
A carburettor is a device that mixes petrol with air and delivers it Into the intake manifold for the engine to burn. If a carburettor is worn or defective it may be the cause of a converter failure. Problems such as improper float adjustments, air/fuel mixture adjustments, out of spec or worn metering rods can cause damage to the catalyst. Also check the choke system to make sure it is operating properly and if the carburettor is an electronic feedback model make sure all adjustments are made according to manufacturer specs and that all feedback sensors or electronic components, such as mixture control solenoids, throttle position sensors and throttle holding solenoids are also operating and are within specs.
FUEL INJECTION SYSTEMS:
Problems in fuel injection systems can also cause problems with the converter. Fuel injection systems differ greatly. Basically a fuel injection system uses small electrically controlled solenoids that deliver or inject fuel into the throttle body or into the intake part of the engine. These little solenoids are controlled by a computer which obtains information from various sensors located through out the engine. These sensors help the computer to determine how much fuel to inject. If an injector is leaking internally or dribbling fuel into the engine it may damage the converter. If the oxygen sensor is defective or the map sensor is bad this can also lead to converter damage. If the injection system uses a cold start injector (which is a small injector that is used to richen the mixture by injecting fuel into the intake air stream when the engine is cold) and if this injector is leaking or dripping, or if it's temperature sensor is not operating properly this too can damage the converter. Because of the many different injection systems used, consult the proper manual when diagnosing this system.
IGNITION SYSTEMS:
Many parts are used in the ignition system. This system delivers the voltage or spark to the appropriate cylinder to fire the engine. Any of the following problems can cause the converter to fail or be damaged, fouled spark plugs, bad spark plug wires, carbon tracked distributor cap or rotor cracked distributor cap. Make sure all spark plugs and wires are firing properly. A misfiring plug not only wastes gas but it make it defective. If the car has a coolant leak into makes converter. Be sure to check distributor timing and vacuum advance for proper operation.
MAP SENSORS:
These sensors tell the ECU how much air is entering the engine as well as the load on the engine. It also monitors barometric pressure. When this sensor fails it can cause a rich condition which can damage the converter. Because testing of these sensors vary between make and model, consult the manual before testing. Generally there are two types, the voltage type and the frequency varying type. To check the voltage type you would use a volt meter and vacuum pump. To check the frequency type you would use a tach and a vacuum pump.
CANISTER PURGE VALVE:
This vacuum-operated valve vents fuel vapours from the carburettor bowl to the charcoal canister. If the diaphragm becomes ruptured, the charcoal canister will flood and the mixture becomes rich and can damage the converter. To check the valve, disconnect the hoses to see if any petrol comes out of the hoses or valve. If there is petrol the valve should be replaced.
EGR SYSTEM
This system routes small amounts of exhaust gasses back to the Intake manifold to reduce oxides of nitrogen or NOX. Systems vary by design so you need to consult the proper manual for the vehicle you are working on. Some newer systems also use an EGR valve position sensor. If the exhaust system you are working on has one it must be checked also. While a bad EGR system will not lead to a converter failure, it might be the reason why the vehicle has a NOX problem.
Automotive Parts & Accessories