What is a catalytic converter?
It is a device which chemically converts harmful exhaust gases, produced by the internal combustion engine, into harmless carbon dioxide and water vapor. The converter was developed to meet stringent emission reduction levels as set forth by the Federal ERA and California Air Resources Board. Since the 1975 model year, vehicle manufacturers have used catalytic converters and other emission control devices, to meet those emission reduction levels.
What is the catalyst?
It is a thin coating of precious metals (rhodium, platinum and paladium) applied to the surface of the substrate material. Its function is to assist in the chemical reactions that are required to lower the emission levels.
What Are Oxidation And Three-Way Converters?
Oxidation converters control two pollutants-carbon monoxide and hydrocarbons. These gases come into the converter accompanied by enough oxygen to result in oxidation (burning) by flameless combustion. They pass through the substrate which causes the oxidation process to speed up changing them into harmless water vapor and carbon dioxide. Three-Way converters (also known as Oxidation/Reduction converters) perform the same function as oxidation converters plus they are designed to reduce levels of oxides of nitrogen. Some three-way converters are equipped with an Air Injection Tube. The additional air, which comes from an air pump, assists the chemical reaction in the oxidation catalyst.
What Makes A Converter Become Red Hot?
If a converter is operated too long at a high temperature, its substrate may "melt down" and turn into a solid mass inside the converter. The vehicle may seem sluggish, as if there were a loss of power. Again, an engine and/or fuel system malfunction is allowing a rich fuel mixture to reach the converter. If the problem is not diagnosed and corrected, future converter failures may occur.
What causes a converter to become clogged?
If the converter is operated for a long period at high temperatures, the substrate material may melt down and form a solid mass inside. It is normally a result of a systems fault that allows a too-rich fuel mixture to reach the converter and it will lead to the engine appearing sluggish and lacking power. Early diagnosis and correction will stop further deterioration in the converter.
How Do You Determine Which Converter To Use?
A vehicle with the wrong type of converter may be considered a tampering violation by the EPA. It is important to use the converters listed in this catalog for the specific applications shown. Sometimes it is difficult to determine what type of converter is on a certain vehicle.
What is A Substrate?
It is the material inside the shell of the converter. There are two types of original equipment substrates: Pelletized, which consists of thousands of BB-sized ceramic pellets and Monolithic, which is a ceramic "honeycomb" style. The replacement converters listed in this catalog have monolithic substrates.
Why Doesn't A Vehicle Pass An Emissions Test?
When a Converter does not function, no exhaust gas conversion takes place. Usually the vehicle will run fine, but it will not pass emission test standards. This may be caused solely by a worn or damaged converter. But, it is difficult to diagnose because it involves other emission system components, as well. The most common cause of this problem is lead contamination within the converter. Use of leaded fuel is usually the source of the contamination.