The catalytic converter is designed to convert harmful emissions, produced by an internal combustion engine, to less-harmful elements: H2O (Water), CO2 (Carbon Dioxide) and N2 (Nitrogen).To perform this conversion, the catalytic converter works with a vehicle's PCM (Powertrain Control Module) and other emissions control devices. OBDII (On-Board Diagnostics Version 2) monitors the emissions control devices and provides feedback on their operating condition. As the EPA (Environmental Protection Agency) updates emissions standards, the OBDII system becomes more sensitive to fluctuations in emissions performance.

OVERHEATED, MELTED OR BROKEN CONVERTERS

Any malfunction causing an unusually high level of HC or CO (in conjunction with high levels of O2) to enter the converter, will dramatically elevate its temperature.

Potential causes for high HC readings may include:
Misfires
AFR Cylinder imbalance
Excessive engine or vehicle load
   - Fuel delivery system or fuel quality
   - Sluggish (worn out) O2 sensors
   - Excessive backpressure
   - Low compression
Poor spark, or weak ignition

NOTE: Temperatures in excess of 1600º F may damage catalyst, without visible signs of melting

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COATED / OIL-FOULED SUBSTRATE

Catalyst poisoning occurs when the converter is exposed to emissions containing substances that coat the working surfaces, enveloping the catalyst to the point it cannot contact and treat the exhaust.

Potential causes for coated or fouled substrate may include:
Excessive carbon build-up in exhaust
Internal coolant leaks (head / intake gasket)
Use of non-converter-safe gasket sealants
Excessive oil consumption (burning oil)
Improper fuels or additives (E85, diesel)

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STRUCTURAL DAMAGE

The primary cause of structural damage is road debris striking the converter. Normally, some evidence ofimpact is visible on the converter shield.

Other conditions that may cause structural damage:
Corrosion
Thermal shock
Metal fatigue
Stress fractures
Stripped O2 Sensor threads
Flex pipe failure
Air-gap pipe failure

Converters will get red hot when excess fuel is introduced directly into it, along with sufficient oxygen to burn the fuel. This is not a problem with the converter itself, but the result of a problem with the fuel system or ignition that allows unburned fuel to pass through the engine and then travel down into the converter. If the root cause is not corrected, the new converter will melt as well. Common causes of a melted converter are: 1) A three-way plus air vehicle running rich, and when the air is injected into the converter, the rear brick will melt as the excessive fuel now has enough oxygen to burn inside the converter, 2) Vehicle is running rich with an exhaust leak, and when the air is drawn into the exhaust pipe and is combined with the excess fuel, it will burn in the converter, 3) The vehicle has a misfire. When the air-fuel charge leaves the combustion chamber without firing, it will travel through the exhaust pipe and burn in the converter.

If a converter is operated too long at a high temperature, the substrate may "melt down" and turn into a solid mass inside the converter. The vehicle may seem sluggish as if there was a loss of power. Other causes might be: 1) upstream converter has broken up and the debris has clogged a down stream unit, 2) the support mat may have become damaged and no longer retaining the brick in the correct position, allowing the brick to shift and block the exhaust flow.

In August, 1986, the U.S. Environmental Protection Agency issued new EPA converter guidelines for the construction, efficiency and installation of aftermarket converters. The converters listed in our catalog have been designed and manufactured to meet the EPA policy and emission reduction requirements. For further questions in regards to using and installing an aftermarket converter, please refer to the following EPA document http://www.epa.gov/otaq/cert/factshts/catcvrts.pdf