Catalytic Converter FAQ

Q What is A Catalytic Converter?

A 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.

Q What is A Substrate?

A 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.

Q What is A Catalyst?

A 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.

Q What Are Oxidation And Three-Way Converters?

A 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.

Q What is the ERA Policy On replacement Converters?

A In August, 1986, the U.S. Environmental Protection Agency issued new guidelines for the construction, efficiency and installation of aftermarket converters. The converters listed in this catalog have been designed, tested, manufactured and proven to meet the ERA policy and emission reduction requirements.

Q What Does the December 18,1986 Cut Off Date Refer to?

A Replacement converters built before December 18, 1986 do not comply with the latest EPA policy. The sale and/or installation of those converters may be prosecuted as a tampering violation of the Clean Air Act. Converters built after that date are in compliance. Those converters are permanently labeled with a date code by the manufacturer. The four digit code refers to the month and year of manufacture (example: “0488” is “April, 1988”).

Q How Do You Determine Which Converter To Use?

A 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.

Q Why Doesn’t A Vehicle Pass An Emissions Test?

A 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.

Q What Makes A Converter Become Red Hot?

A A Converter will get red hot when raw fuel is introduced directly into it. This is not the problem of the converter itself, but the result of a problem with the fuel system or ignition that allows unburned fuel to pass through the engine to the converter. Possible causes are improper ignition timing, fouled spark plugs, and air pump failure.

Q What Causes A Converter To Become Clogged?

A 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.

Q What Causes The Replacement Rubber Air Hose To Burn or Melt?

A The air pump or check Valve could be malfunctioning. The universal hoses listed in this catalog are made of a high temperature (up to 550° F) Silicone rubber. Their purpose is to transport air (up to 125° F) to the converter. Under proper operating conditions they will not burn or melt. However, if hot exhaust gases back-up from the converter into the hose, damage could occur.

Q Why Does The Exhaust Have A “Rotten Egg” Smell?

A Many times on first start-up in the morning, the exhaust may smell like “rotten eggs”. This is due to rich fuel condition with a cold engine. However, as the engine warms up, this smell should go away. If it does not, converter damage could possibly follow with extended driving.

Q What Is The Converter Warranty?

A The converters listed in this catalog are warranteed to meet the Federal ERA emission reduction requirement for 25,000 miles. Also, the converter shell is warranteed for five years or 50,000 miles, whichever occurs first.

Q What Should Be Done With The Warranty Card?

A The registration section must be filled in by the installer and mailed to the address indicated. The warranty statement and sales receipt should be kept by the consumer for future reference.