Exhaust System: Description and Operation
The 3.0L (2V) and 3.0L (4V) engines are equipped with the following:^ muffler
^ dual converter Y pipe
^ exhaust system flex tube
^ muffler pipe brackets
^ muffler bracket lower support.
The 3.4L engine is equipped with the following:
^ muffler
^ dual converter Y pipe
^ exhaust system flex tube
^ muffler pipe bracket
^ muffler bracket low support
^ three-way catalytic converter.
The production exhaust system shown differs from the service replacement system in the number of basic pieces used.
Three Way Catalytic Converter (TWC)
The three way catalytic converters are integral to the dual converter Y pipe and:
^ play a major role in the emission control system in order to reduce air pollutants.
^ work as a gas reactor,
^ catalyst material inside the three way catalytic converter is made of a ceramic substrate that is coated with a high surface area alumina and impregnated with catalytically active platinum, palladium or rhodium.
^ the surface of the catalyst material plays a major role in the heat producing chemical reaction.
Precautions
The following precautions must be observed when operating a vehicle equipped with three way catalytic converters.
If a vehicle is continually misfueled:
^ the lead in the fuel will be deposited in the converter and completely blanket the catalyst.
^ lead combines chemically with platinum to damage the catalyst.
^ continuous use of leaded fuels can destroy the catalyst and render the converter useless.
The addition of lead to the converter can also solidify the catalyst, causing:
^ excessive back pressure in the exhaust system.
^ possible engine damage.
Extremely high temperatures of 1100°C (2012°F) or over, due to misfiring or over-rich fuel/air mixture, will cause the ceramic base to sinter or burn, destroying the converter.
The three way catalytic converter has been designed to provide a long service life. No maintenance is necessary for the three way catalytic converter, however, avoid the following conditions:
^ Do not drive downhill with the gears engaged and the ignition switch OFF.
^ Do not drive with misfiring engine.
^ Do not run the engine continuously with a misfiring spark plug.
Exhaust Shields
Exhaust shields, consisting of formed metal sheets, attach to the exhaust system or the dual converter Y pipe using various methods.
Service/Replacement
Exhaust shields are not subject to service other than:
^ replacing missing or damaged attaching parts such as clamps or screws.
^ removing debris that may collect in the shield area.
If an exhaust shield is damaged or shows evidence of Deterioration, it must be replaced rather than serviced.