Toyota Pick-ups/Land Cruiser/4Runner 1989-1996

Catalytic Converter



The catalytic converter is a muffler-like container built into the exhaust system to aid in the reduction of exhaust emissions. When the exhaust gases come into contact with the catalyst, a chemical reaction occurs which reduces the pollutants into harmless substances such as water and carbon dioxide.

There are two types of catalytic converters: an oxidizing type and a three-way type. Both are used on Toyota trucks, although the oxidation type is found only with the 22R engine. The oxidizing catalyst requires the addition of oxygen to spur the catalyst into reducing the engine's HC and CO emissions into H 2 O and CO 2 .


Use only unleaded fuel.
Avoid prolonged idling; the engine should run no longer than 20 min. at curb idle and no longer than 10 min. at fast idle.
Don't disconnect any of the spark plug leads while the engine is running. If any engine testing procedure requires disconnecting or bypassing a control component, perform the procedure as quickly as possible. A mis-firing engine can overheat the catalyst and damage the oxygen sensor.
Make engine compression checks as quickly as possible.
Whenever under the vehicle or around the catalytic converter, remember that it has a very high outside or skin temperature. During operation, the catalyst reach high temperatures to work efficiently. Be very wary of burns, even after the engine has been shut off for a while. Additionally, because of the heat, never park the vehicle on or over flammable materials, particularly dry grass or leaves. Inspect the heat shields frequently and correct any bends or damage.
In the unlikely event that the catalyst must be replaced, DO NOT dispose of the old one where anything containing grease, gas or oil can come in contact with it. The catalytic action with these substances will result in heat which may start a fire.