Substrate 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.
Catalyst 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.
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.
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").
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.
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.
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.
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.
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.