Catalytic Converters should not fail under normal vehicle operating conditions. There are no moving parts and the catalyst is never Used Up”. The converter should last the life of the vehicle. However, several other components in the emission control system can fail or deteriorate with time and use. These failing components are often the cause of a catalytic converter failure. Early detection of these components will reduce the risk of a failure and, when a converter failure does occur, it is essential to find the “True” cause of the failure and fix or replace the component that led to the failure. Just replacing the failed converter will not fix the problem.
Engine Tune-Up Required
A number of problems could occur to the catalytic converter as the result of an engine that is out of tune. Any time an engine is operating outside proper specifications, unnecessary wear and damage may be caused to the catalytic converter as well as the engine itself. The damage is often the result of an incorrect air/fuel mixture, incorrect timing, or misfiring spark plugs. Any of these conditions could lead to a catalytic converter failure.
Excess Fuel Entering Exhaust
The fuel that powers your vehicle is meant to burn in the combustion chamber only. Any fuel that leaves the combustion chamber unburned will enter the exhaust system and light-off when it reaches the catalytic converter. This can super-heat the converter far above normal operating conditions and cause a Converter Meltdown. Possible causes are an incorrect fuel mixture, incorrect timing, corroded spark plugs, a faulty oxygen sensor, sticking float, faulty fuel injector or a malfunctioning check valve.
Oil or Antifreeze Entering Exhaust
Oil or Antifreeze entering the exhaust system can block the air passages by creating a heavy carbon soot that coats the ceramic catalyst. These heavy Carbon Deposits create two problems. First, the carbon deposits prevent the catalytic converter from reducing harmful emission in the exhaust flow. And second, the carbon deposits clog the pores in the ceramic catalyst and block exhaust flow, increasing back pressure and causing heat and exhaust to back up into the engine compartment. Your engine may actually draw burnt exhaust gasses back into the combustion chamber and dilute the efficiency of the next burn cycle. The result is a loss of power and overheated engine components. Possible causes are worn piston rings, faulty valve seals, failed gaskets or warped engine components.
Deteriorated Spark Plug or Spark Plug Wires
Spark plugs that don’t fire or misfire cause unburned fuel to enter the exhaust system. The unburned fuel ignites inside the converter and could result in a partial or complete meltdown of the ceramic catalyst. Spark plugs and spark plug wires should be checked regularly and replaced if damaged or if wires are worn or cracked.
Oxygen Sensor Not Functioning Properly
An oxygen sensor failure can lead to incorrect readings of exhaust gasses. The faulty sensor can cause a too rich or too lean condition. Too rich, and the catalyst can melt down. Too lean, and the converter is unable to convert the hydrocarbons into safe elements and may not pass a state inspection.
Road Damage or Broken Hangers
The ceramic catalyst inside a catalytic converter is made from a lightweight, thin-walled, fragile material. It is protected by a dense, insulating mat. This mat holds the catalyst in place and provides moderate protection against damage. However, rock or road debris striking the converter or improper or broken exhaust system support can cause a Catalyst Fracture. Once the ceramic catalyst is fractured, the broken pieces become loose and rattle around and break up into smaller pieces. Flow is interrupted and back-pressure in the exhaust system increases. This leads to heat build-up and loss of power. Possible causes of a catalyst fracture are road debris striking the converter, loose or broken hangers, potholes or off-road driving.
The purpose of a catalytic converter is to reduce harmful emissions from the exhaust of a “Properly Tuned” combustion engine. It accomplishes this through heat and a precious metal catalyst that causes the harmful emissions to either oxidize or reduce to safe elements in the exhaust flow. If the engine is out-of-tune and not calibrated to OEM specs, the catalytic converter’s efficiency is greatly diminished and could lead to a converter failure.
The precious metal catalyst is bound to an extruded ceramic honeycomb substrate. The ceramic has hundreds of flow channels that allow the exhaust gasses to come in contact with a maximum amount of surface area where the catalyst reaction takes place. The catalyst must come in direct contact with the exhaust gasses for the reaction to take place.
If the ceramic inside your converter becomes clogged or coated with carbon, lead, oil, antifreeze, or silicone, then the converters efficiency is greatly reduced.
There are three basic types of automotive catalytic converters; Two-Way, Three-Way and Three-Way + Air. Each type uses a slightly different method and chemistry to reduce the harmful elements in exhaust emissions. Early model converters used a pelletized catalyst, but most modern converters are now designed with a free-flowing honeycomb ceramic catalyst. The type of converter required on a particular vehicle varies with model year, engine size and vehicle weight. Some vehicles even make use of more than one type of converter or a pre-converter to meet emission reduction standards.
AFTERMARKET CONVERTERS FOR OBDII EQUIPPED VEHICLES
Late model (generally 1996 and later) cars and trucks have On-Board Diagnostic (OBDII) systems designed to detect catalyst failures. These vehicles often use 2 or more catalytic converters and have oxygen sensors in front and behind one or more of the converters. In nearly all cases, these sensors are located in the exhaust pipe. The vehicle’s on-board computer compares the oxygen sensor signals before and after the converter(s) to determine if the converter is working correctly.
CARB California
Currently, aftermarket catalytic converters have not been officially approved by any government agency for vehicles with OBDII systems. The California Air Resources Board (ARB) does test and approve aftermarket converters and its approvals are accepted by all other states and many other countries. The ARB is developing new, tougher tests for these converters but has NOT finalized the procedure and has NOT approved any aftermarket OBDII converters. In California, no aftermarket converter company’s converters can be used on OBDII vehicles because none have been approved.
EPA National
Outside CA, aftermarket converters may be used on OBDII vehicles as long as the following guidelines are followed:
The original converter is defective as shown by emission tests, the OBDII system or the converter is physically damaged, and the converter is no longer covered by the OEM vehicle warranty.
The aftermarket converter is selected based on the vehicle weight, engine size, and physical fit.
The location of the converter must be the same as the OEM converter.
The location of the oxygen sensor(s) must be the same as in the OEM exhaust system and can not be relocated.
The diagnostic codes should be cleared according to the vehicle manufacturer’s procedure after changing the converter otherwise the on-board computer may turn on the “Check Engine” light.
Aftermarket catalytic warranty terms and conditions remain unchanged as stated on the warranty certificate.
Check Diagnostic Codes Before Replacing Any OBDII Converter. “Check Engine Light” may indicate failure other than catalyst.
ORIGINAL WARRANTY CERTIFICATE AND INSTALLATION STATEMENT (green)
To be completely filled out by the installer and returned to manufacturer. Include dealer name, complete address and phone number. Include customer name, complete address and phone number. Vehicle make, year, model, engine size, mileage and date must be filled out. The part number installed must be filled out. The Installation Statement must be completed by installer, stating the reason for replacement. Vehicle owner and installer must sign and date the Warranty Certificate/Installation Statement.
CATALYTIC CONVERTER WARRANTY CERTIFICATE
The manufacturer warrants that its catalytic converters are free from defects in materials and workmanship. This catalytic converter has been designed and manufactured to meet State and Federal emission reduction requirements; and, when the vehicle is properly maintained, the catalytic converter is warranted to meet such requirements for 25,000 miles from the time of installation and it will not constitute a safety hazard. The manufacturer warrants its catalytic converters external shell, including end pipes, to last for 5 years or 50,000 miles, which ever comes first, from the date of installation. This catalytic converter has been designed and manufactured to meet these warranty requirements.
The manufacturer’s warranty is void if the catalytic converter is not properly installed on the vehicle for which it is designed and cataloged; if the catalytic converter has been altered or repaired or damaged by negligence, accident or mishandling. The manufacturer assumes no liability for catalytic converter failures related to engines not operating within original equipment specifications, to vehicles with modified exhaust emission control systems or to the use of leaded fuel.
The manufacturer will replace any such defective converter provided that it be returned to an authorized dealer along with proof of purchase and properly completed warranty certificate. If warranty claim relates to emission performance, proof of failure of an emission test must be provided. Documentation showing the vehicle’s current state of tune is also required. The manufacturer reserves the right to determine what constitutes vehicle’s proper operating condition. No other warranty expressed or implied, including merchantability, applies to the catalytic converter, nor is any person or company authorized to assume any other warranty. The manufacturer does not assume any responsibility for any consequential damages occasioned by the catalytic converter, or inconvenience or interruption in any operation.
This warranty gives you specific legal rights. You may also have other rights which vary from state to state.
WARNING
An improperly tuned engine will cause damage to a catalytic converter. Be sure the engine is properly tuned to manufacturer’s specifications and that emission control equipment is operating within original equipment specifications before installing this new catalytic converter. If the new converter is being used to replace a failed converter, it is possible the same problem, if not corrected, will cause damage to this new converter.
An improperly tuned or misfiring engine can allow unburned gasoline to enter the converter, causing extremely high temperatures that can result in melted, plugged or broken internal substrates. This situation voids the warranty.
Catalytic Converter Warranty Statement – INSTALLER’S COPY (Canary)
To be retained by Installer with copy of the invoice for six (6) months.
Catalytic Converter Warranty Statement – FAILED CONVERTER COPY (Pink)
Attach this copy to the failed OEM converter and retain for 15 days. Catalytic
Converter Warranty Statement – CUSTOMER’S COPY (White)
To be retained by the vehicle owner along with invoice and proof of vehicle tune-up.