Pickup 2WD L4-2254cc 2.3L SOHC (4ZD1) MFI (1994)
_mfi/Page-315001.png)
Three Way Catalytic (TWC) Converter: Description and Operation
California
Catalytic Converter
PURPOSE
Reduces exhaust emissions.
LOCATION
Two (2) catalytic converters are used downstream of the exhaust manifold to reduce oxides of nitrogen (NOx) and oxidize hydrocarbons (HC) and
carbon monoxide (CO).
OPERATION and CONSTRUCTION
The rear three-way converter contains the catalyst elements platinum, rhodium and palladium which promote oxidation and reduction reactions at
high temperatures. Emissions are converted into carbon dioxide, water vapor and nitrogen.
An oxidizing catalyst, mounted directly in the exhaust manifold, is also used to oxidize excess hydrocarbons that occur in the exhaust when the
engine is cold.
