EXHAUST SYSTEM
TABLE OF CONTENTS
page page
DESCRIPTION AND OPERATION
EXHAUST SYSTEM........................1
CATALYTIC CONVERTERS ..................1
HEAT SHIELDS ...........................3
DIAGNOSIS AND TESTING
EXHAUST SYSTEM........................3
REMOVAL AND INSTALLATION
EXHAUST SYSTEM........................4
MUFFLER AND FRONT RESONATOR ..........5
TAILPIPE/REAR RESONATOR................6
CATALYTIC CONVERTERS ..................6
CLEANING AND INSPECTION
EXHAUST SYSTEM........................7
ADJUSTMENTS
EXHAUST SYSTEM ALIGNMENT .............7
SPECIFICATIONS
TORQUE ................................8
DESCRIPTION AND OPERATION
EXHAUST SYSTEM
WARNING: THE NORMAL OPERATING TEMPERA-
TURE OF THE EXHAUST SYSTEM IS VERY HIGH.
THEREFORE, NEVER WORK AROUND OR ATTEMPT
TO SERVICE ANY PART OF THE EXHAUST SYSTEM
UNTIL IT IS COOLED. SPECIAL CARE SHOULD BE
TAKEN WHEN WORKING NEAR THE CATALYTIC
CONVERTER. THE TEMPERATURE OF THE CON-
VERTER RISES TO A HIGH LEVEL AFTER A SHORT
PERIOD OF ENGINE OPERATION TIME.
DESCRIPTION
The exhaust system (Fig. 1) consist of two front
close coupled catalytic converters. Both converters
attach directly to the exhaust manifold using a
V-Band clamp. The exhaust down pipes exit the con-
verters and connect into the front resonator. The
front resonator, intermediate pipe, and muffler are
one single module. The rear resonator and tailpipe
connect to the muffler outlet. The upstream oxygen
sensors are located in each exhaust manifold. The
downstream oxygen sensors are located at the rear of
each catalytic converter.
OPERATION
The exhaust system channels the exhaust gases
created by engine to the rear of the vehicle. The muf-
fler and resonator quiets the exhaust noises. The cat-
alytic converter reduces exhaust emissions.
CATALYTIC CONVERTERS
DESCRIPTION
The close coupled, three-way catalytic converter
inlets are connected to the exhaust manifolds by the
use of V-Band clamps (Fig. 2). The left side converter
outlet pipe connects to the exhaust system. The right
side converter connects to an extension pipe (Fig. 2).
OPERATION
The three-way catalytic converter simultaneously
converts three exhaust emissions into harmless
gases. Specifically, HC and CO emissions are con-
verted into water (H2O) and carbon dioxide (CO2).
Oxides of Nitrogen (NOx) are converted into elemen-
tal Nitrogen (N) and water. The three-way catalyst is
most efficient in converting HC, CO and NOx at the
stoichiometric air fuel ratio of 14.7:1.
The oxygen content in a catalyst is important for
efficient conversion of exhaust gases. When a high
oxygen content (lean) air/fuel ratio is present for an
extended period, oxygen content in a catalyst can
reach a maximum. When a rich air/fuel ratio is
present for an extended period, the oxygen content in
the catalyst can become totally depleted. When this
occurs, the catalyst fails to convert the gases. This is
known as catalyst “punch through.9
Catalyst operation is dependent on its ability to
store and release the oxygen needed to complete the
emissions-reducing chemical reactions. As a catalyst
deteriorates, its ability to store oxygen is reduced.
Since the catalyst’s ability to store oxygen is some-
what related to proper operation, oxygen storage can
be used as an indicator of catalyst performance.
Refer to the appropriate Powertrain Diagnostic Pro-
cedure for diagnosis of a catalyst related Diagnostic
Trouble Code (DTC).
LH EXHAUST SYSTEM 11 - 1
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