Exhaust System: Description and Operation

Exhaust System
The vehicle exhaust system consists of the following components:
^ muffler
^ tailpipe
^ muffler inlet pipe
^ muffler outlet pipe and resonator
^ catalytic converter
^ heat shields
^ hangers
^ hanger insulators
^ flexible pipe
The exhaust system provides an exit for exhaust gases and reduces engine noise by passing exhaust gases through the Three-Way Catalytic Converter (TWC), muffler inlet pipe and resonator, and muffler. Rubber exhaust hanger insulators attach the exhaust system to mounting hangers.

Three-Way Catalytic Converter (TWC)
The Three-Way Catalytic Converter (TWC) plays a major role in the emission control system. The TWC operates as a gas reactor. Its catalytic function is to speed the heat-producing chemical reaction of components in the exhaust gases in order to reduce air pollutants.
The catalyst material inside the TWC consists of a ceramic substrate. The substrate is coated with a high-surface area alumina and contains chemically active palladium. The front catalytic converter is integrated into the left side exhaust manifold.

Precautions

WARNING: The normal operating temperature of the exhaust system is very high. Never work around or attempt to repair any part of the exhaust system until it has cooled. Use special care when working around the three-way catalytic converter. The three-way catalytic converter heats to a high temperature after only a short period of engine operation.

WARNING: Exhaust gases contain carbon monoxide which can be harmful to health and is potentially lethal. Exhaust system leaks should be repaired immediately. Never operate the engine in enclosed areas.

In a vehicle that is continually misfueled, lead in the fuel will be deposited in the TWC and completely blanket the catalyst. Lead reacts with platinum to poison the catalyst. Continuous use of leaded fuel can destroy the catalyst and render the TWC useless. The addition of lead to the TWC can also solidify the catalyst, causing excessive back pressure in the exhaust system and possibly causing engine damage.
Extremely high temperatures of 1,100°C (2,012°F) or above due to misfiring or an over-rich fuel/air mixture will cause the ceramic base to sinter or burn, destroying the TWC.
The TWC is designed to provide a long service life. No maintenance is necessary for the TWC. Avoid the following conditions:
^ driving with a misfiring engine
^ continuously running the engine with a misfiring spark plug
^ parking or stopping the vehicle over combustible material such as dry grass (The material can be ignited by the high temperatures of the TWC and muffler.)

Sound Insulators and Shields
Sound insulators and shields protect the vehicle from exhaust system heat and should be inspected at regular intervals to make sure they are not dented or out of position. If a sound insulator and shield is damaged or shows evidence of deterioration, a new one should be installed. The sound insulators and shields for the muffler, muffler pipe, resonator, and TWC pipe are installed separately.
Sound insulators and shields that are attached to the TWC are not repaired other than to install new attaching parts such as clamps or screws, and to remove foreign material that may collect in the shield area.