catalytic converter CHRYSLER VOYAGER 2004 Service Manual

ence these symptoms, try another brand of gasoline
before considering service for the vehicle.
Over 40 auto manufacturers world-wide have
issued and endorsed consistent gasoline specifications
(the Worldwide Fuel Charter, WWFC) to define fuel
properties necessary to deliver enhanced emissions,
performance and durability for your vehicle. We rec-
ommend the use of gasolines that meet the WWFC
specifications if they are available.
REFORMULATED GASOLINE
Many areas of the country require the use of
cleaner burning gasoline referred to as ªreformu-
latedº gasoline. Reformulated gasoline contain oxy-
genates, and are specifically blended to reduce
vehicle emissions and improve air quality.
We strongly support the use of reformulated gaso-
line. Properly blended reformulated gasoline will pro-
vide excellent performance and durability for the
engine and fuel system components.
GASOLINE/OXYGENATE BLENDS
Some fuel suppliers blend unleaded gasoline with
oxygenates such as 10% ethanol, MTBE, and ETBE.
Oxygenates are required in some areas of the country
during the winter months to reduce carbon monoxide
emissions. Fuels blended with these oxygenates may
be used in your vehicle.
CAUTION: DO NOT use gasoline containing METH-
ANOL. Gasoline containing methanol may damage
critical fuel system components.
MMT IN GASOLINE
MMT is a manganese-containing metallic additive
that is blended into some gasoline to increase octane.
Gasoline blended with MMT provide no performance
advantage beyond gasoline of the same octane num-
ber without MMT. Gasoline blended with MMT
reduce spark plug life and reduce emission system
performance in some vehicles. We recommend that
gasoline free of MMT be used in your vehicle. The
MMT content of gasoline may not be indicated on the
gasoline pump; therefore, you should ask your gaso-
line retailer whether or not his/her gasoline contains
MMT.
It is even more important to look for gasoline with-
out MMT in Canada because MMT can be used at
levels higher than allowed in the United States.
MMT is prohibited in Federal and California refor-
mulated gasoline.
SULFUR IN GASOLINE
If you live in the northeast United States, your
vehicle may have been designed to meet California
low emission standards with Cleaner-Burning Cali-fornia reformulated gasoline with low sulfur. If such
fuels are not available in states adopting California
emission standards, your vehicles will operate satis-
factorily on fuels meeting federal specifications, but
emission control system performance may be
adversely affected. Gasoline sold outside of California
is permitted to have higher sulfur levels which may
affect the performance of the vehicle's catalytic con-
verter. This may cause the Malfunction Indicator
Lamp (MIL), Check Engine or Service Engine Soon
light to illuminate. We recommend that you try a dif-
ferent brand of unleaded gasoline having lower sulfur
to determine if the problem is fuel related prior to
returning your vehicle to an authorized dealer for
service.
CAUTION: If the Malfunction Indicator Lamp (MIL),
Check Engine or Service Engine Soon light is flash-
ing, immediate service is required; see on-board
diagnostics system section.
MATERIALS ADDED TO FUEL
All gasoline sold in the United States and Canada
are required to contain effective detergent additives.
Use of additional detergents or other additives is not
needed under normal conditions.
FUEL SYSTEM CAUTIONS
CAUTION: Follow these guidelines to maintain your
vehicle's performance:
²The use of leaded gas is prohibited by Federal
law. Using leaded gasoline can impair engine perfor-
mance, damage the emission control system, and
could result in loss of warranty coverage.
²An out-of-tune engine, or certain fuel or ignition
malfunctions, can cause the catalytic converter to
overheat. If you notice a pungent burning odor or
some light smoke, your engine may be out of tune or
malfunctioning and may require immediate service.
Contact your dealer for service assistance.
²When pulling a heavy load or driving a fully
loaded vehicle when the humidity is low and the tem-
perature is high, use a premium unleaded fuel to
help prevent spark knock. If spark knock persists,
lighten the load, or engine piston damage may result.
²The use of fuel additives which are now being
sold as octane enhancers is not recommended. Most
of these products contain high concentrations of
methanol. Fuel system damage or vehicle perfor-
mance problems resulting from the use of such fuels
or additives is not the responsibility of
DaimlerChrysler Corporation and may not be covered
under the new vehicle warranty.
RSLUBRICATION & MAINTENANCE0-5
FLUID TYPES (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
3. Obstructions in heater hose
fitting at engine or at heater core.3. Remove heater hoses at both
ends and check for obstructions.
Repair as necessary.
4. Heater hose kinked. 4. Locate kinked area and repair as
necessary.
5. Water pump is not pumping
coolant to heater core.5. When the engine is fully warmed
up, both heater hoses should be hot
to the touch. If only one of the
hoses is hot, the water pump may
not be operating correctly. Replace
components as necessary.
6. Air trapped in heater core. 6. (Refer to 7 - COOLING -
DIAGNOSIS AND TESTING -
COOLING SYSTEM DEAERATION)
HEAT ODOR 1. Various heat shields are used at
certain driveline components. One
or more of these shields may be
missing.1. Locate missing shields and
replace or repair as necessary.
2. Temperature gauge reading
above the normal range.2. Refer to Gauge Is Reading High
in Temperature Gauge Indicatication
Diagnosis Chart.
3. Radiator fan operating
incorrectly.3. (Refer to 7 - COOLING/ENGINE/
RADIATOR FAN - OPERATION)
Repair as necessary.
4. Undercoating been applied to an
unnecessary component.4. Clean undercoating as necessary.
5. Engine may be running rich,
causing the catalytic converter to
overheat5. (Refer to Appropriate Diagnostic
Information) Repair as necessary.
POOR DRIVEABILITY
(THERMOSTAT POSSIBLY STUCK
OPEN). GAUGE MAY BE READING
LOW.1. The engine thermostat must be
operating correctly for proper
driveability, clean vehicle emissions,
and the prevention of sludge
buildup in the engine oil. Check for
a diagnostic trouble code.1. (Refer to Appropriate Diagnostic
Information) Replace thermostat, if
necessary.
STEAM IS COMING FROM FRONT
OF VEHICLE NEAR GRILL AREA
WHEN WEATHER IS WET,
ENGINE WARMED UP AND
RUNNING WITH VEHICLE
STATIONARY, OR JUST SHUT
OFF. TEMPERATURE GAUGE IS
NORMAL.1. During wet weather, moisture
(snow, ice, rain, or condensation)
on the radiator will evaporate when
the thermostat opens. The
thermostat opening allows heated
coolant into the radiator. When the
moisture contacts the hot radiator,
steam may be emitted. This usually
occurs in cold weather with no fan
or air flow to blow it away.1. Occasional steam emitting from
this area is normal. No repair is
necessary.
7 - 16 ENGINERS
ENGINE (Continued)

(18) Remove axle shafts. (Refer to 3 - DIFFEREN-
TIAL & DRIVELINE/HALF SHAFT - REMOVAL)
(19) Drain engine oil and remove oil filter. (Refer
to 9 - ENGINE/LUBRICATION/OIL - STANDARD
PROCEDURE)
(20) Remove crossmember cradle plate (Fig. 6).
(21) Disconnect exhaust pipe from manifold (Fig.
7).
(22) Remove engine front mount and bracket from
engine. (Refer to 9 - ENGINE/ENGINE MOUNTING/
FRONT MOUNT - REMOVAL)(23) Remove structural collar. (Refer to 9 -
ENGINE/ENGINE BLOCK/STRUCTURAL COVER -
REMOVAL)
(24) Remove rear engine mount bracket. (Refer to
9 - ENGINE/ENGINE MOUNTING/REAR MOUNT -
REMOVAL)
(25) Mark flex plate to torque converter and
remove torque converter bolts.
(26) Pinch-off power steering supply hose at pump.
Remove hose from pump.
(27) Remove and set aside the power steering
pump and bracket. Do not disconnect pressure line.
(28) Lower vehicle.
(29) Remove A/C lines at compressor and cap open-
ings.
(30) Remove engine ground straps (strap at engine
right mount and at starter).
(31) Raise vehicle enough to allow engine dolly
Special Tool 6135, cradle Special Tool 6710 with
Posts Special Tool 6848 to be installed under vehicle
(Fig. 8).
(32) Loosen cradle posts to allow movement for
proper positioning. Locate two rear posts (right side
of engine) into the holes on the engine bedplate.
Locate the two front posts (left side of engine) on the
oil pan rails (Fig. 8). Lower vehicle and position cra-
dle mounts until the engine is resting on mounts.
Tighten mounts to cradle frame. This will keep
mounts from moving when removing or installing
engine and transmission.
(33) Install safety straps around the engine to cra-
dle. Tighten straps and lock.
(34) Lower vehicle so the weight ofONLY THE
ENGINE AND TRANSMISSIONare on the cradle.
(35) Remove engine and transmission mount bolts.
(36) Raise vehicle slowly. It may be necessary to
move the engine/transmission assembly with the
dolly to allow for removal around the body.
Fig. 6 Crossmember Cradle Plate
1 - CRADLE PLATE
Fig. 7 Catalytic Converter to Exhaust Manifold
1 - CATALYTIC CONVERTER
2 - BOLT
3 - GASKET
4 - FLAG NUT
9 - 14 ENGINE 2.4LRS
ENGINE 2.4L (Continued)

(11) Disconnect the throttle cables from the throt-
tle body.
(12) Disconnect the MAP, IAC, and TPS electrical
connectors.
(13) Disconnect the EGR transducer electrical con-
nector (if equipped).
(14) Disconnect the vacuum hoses from throttle
body.
(15) Disconnect the brake booster and speed con-
trol vacuum hoses.
(16) Disengage wire harness clip from the right
side engine mount.
(17) Remove the power steering reservoir from
mounting position and set aside.Do notdisconnect
hose.
(18) Disconnect ground strap from rear of cylinder
head.
(19) Disconnect engine coolant temperature (ECT)
sensor and ignition coil electrical connectors.
(20) Disconnect the fuel injector electrical harness
connector and disengage clip from support bracket.
(21) Disconnect camshaft and crankshaft position
sensor electrical connectors.
(22) Evacuate air conditioning system. Refer to 24
- HEATING & AIR CONDITIONING.
(23) Disconnect A/C compressor electrical connec-
tor.
(24) Disconnect the A/C lines from compressor.
Cover and seal all openings of hoses and compressor.
(25) Remove the radiator upper hose.
(26) Disengage electrical harness clip at transaxle
dipstick tube.
(27) Remove transaxle dipstick tube. Seal opening
using a suitable plug.
NOTE: When the transaxle cooler lines are removed
from the rolled-groove type fittings at the transaxle,
damage to the inner wall of the hose will occur. To
prevent prevent potential leakage, the cooler hoses
must be cut off flush at the transaxle fitting, and a
service cooler hose splice kit must be installed
upon reassembly.
(28) Using a blade or suitable hose cutter, cut
transaxle oil cooler lines off flush with fittings. Plug
cooler lines and fittings to prevent debris from enter-
ing transaxle or cooler circuit. A service splice kit will
be installed upon reassembly.
(29) Disconnect transaxle shift linkage and electri-
cal connectors.
(30)
Raise vehicle on hoist and drain the engine oil.
(31) Remove the axle shafts. (Refer to 3 - DIFFER-
ENTIAL & DRIVELINE/HALF SHAFT - REMOVAL)
(32) Remove crossmember cradle plate (Fig. 6).
(33)AWD equipped:Remove the power transfer
unit (PTU) (Refer to 21 - TRANSMISSION/TRANS-
AXLE/POWER TRANSFER UNIT - REMOVAL).(34) Disconnect exhaust pipe from the manifold
(Fig. 7).
(35) Remove front engine mount and bracket as an
assembly.
(36) Remove the engine rear mount bracket.
(37) Remove the engine to transaxle struts (Fig. 8).
(38) Remove transaxle case cover (Fig. 8).
(39) Remove flex plate to torque converter bolts.
Mark torque converter to flex plate for orientation for
reassembly.
(40) Remove the power steering pressure hose sup-
port clip attaching bolt.
Fig. 6 Crossmember Cradle Plate
1 - CRADLE PLATE
Fig. 7 Catalytic Converter to Exhaust Manifold
1 - FLAG NUT
2 - GASKET
3 - BOLT
4 - CATALYTIC CONVERTER
RSENGINE 3.3/3.8L9-87
ENGINE 3.3/3.8L (Continued)

(11) Fill the cooling system. (Refer to 7 - COOL-
ING - STANDARD PROCEDURE)
EXHAUST MANIFOLD - RIGHT
REMOVAL
(1) Disconnect battery negative cable.
(2) Remove the wiper module. (Refer to 8 - ELEC-
TRICAL/WIPERS/WASHERS/WIPER MODULE -
REMOVAL)
(3) Disconnect spark plug wires.
(4) Remove bolts fastening crossover pipe to
exhaust manifold (Fig. 124).
(5) Disconnect and remove the upstream oxygen
sensor (Fig. 127).(6) Remove the heat shield attaching screws (Fig.
127).
(7) Remove the upper heat shield (Fig. 127).
(8) Raise vehicle on hoist and remove drive belt
shield.
(9) Loosen the power steering pump support strut
lower bolt (Fig. 125).
(10) Disconnect downstream oxygen sensor connec-
tor.
(11) Disconnect catalytic converter pipe from
exhaust manifold (Fig. 126).
Fig. 123 LOWER MANIFOLD TIGHTENING
SEQUENCE
Fig. 124 CROSS-OVER PIPE
1 - CROSS-OVER PIPE
2 - BOLT
3 - GASKET
4 - FLAG NUT
Fig. 125 P/S PUMP STRUT
1 - BOLT - LOWER
2 - STRUT - P/S PUMP
3 - BOLT - UPPER
Fig. 126 Catalytic Converter to Exhaust Manifold
1 - FLAG NUT
2 - GASKET
3 - BOLT
4 - CATALYTIC CONVERTER
9 - 150 ENGINE 3.3/3.8LRS
INTAKE MANIFOLD - LOWER (Continued)

(12) Lower vehicle and remove the power steering
pump support strut upper bolt (Fig. 125).
(13) Remove bolts attaching exhaust manifold to
cylinder head and remove manifold (Fig. 127).
(14) Inspect and clean manifold. (Refer to 9 -
ENGINE/MANIFOLDS/EXHAUST MANIFOLD -
CLEANING) (Refer to 9 - ENGINE/MANIFOLDS/
EXHAUST MANIFOLD - INSPECTION)
CLEANING
(1) Discard gasket (if equipped) and clean all sur-
faces of manifold and cylinder head.
INSPECTION
Inspect exhaust manifolds for damage or cracks
and check distortion of the cylinder head mounting
surface and exhaust crossover mounting surface with
a straightedge and thickness gauge (Fig. 128).
Manifold surface flatness limits should not exceed
1.0 mm (0.039 in.).
INSTALLATION
(1) Position exhaust manifold on cylinder head and
install bolts to center runner (cylinder #3) and initial
tighten to 2.8 N´m (25 in. lbs.) (Fig. 127)
(2) Using a new gasket, attach crossover pipe to
exhaust manifold and tighten bolts to 41 N´m (30 ft.
lbs.) (Fig. 124).NOTE: Inspect crossover pipe fasteners for damage
from heat and corrosion. The cross-over bolts are
made of a special stainless steel alloy. If replace-
ment is required, OEM bolts are highly recom-
mended.
(3) Install the remaining manifold attaching bolts.
Tighten all bolts to 23 N´m (200 in. lbs.).
(4) Position the power steering pump support strut
and install upper bolt (Fig. 125).
(5) Install heat shield and attaching screws (Fig.
127).
(6) Install and connect upstream oxygen sensor
(Fig. 127).
(7) Raise the vehicle.
(8) Attach catalytic converter pipe to exhaust man-
ifold using new gasket and tighten bolts to 37 N´m
(27 ft. lbs.) (Fig. 126).
(9) Connect downstream oxygen sensor connector.
(10) Tighten the power steering pump support
strut lower bolt (Fig. 125).
(11) Install the belt splash shield and lower the
vehicle.
(12) Install the wiper module. (Refer to 8 - ELEC-
TRICAL/WIPERS/WASHERS/WIPER MODULE -
INSTALLATION)
(13) Connect battery negative cable.
Fig. 127 EXHAUST MANIFOLD - RIGHT
1 - SCREW - HEAT SHIELD
2 - HEAT SHIELD - UPPER
3 - BOLT - EXHAUST MANIFOLD
4 - HEAT SHIELD - LOWER
5 - EXHAUST MANIFOLD - RIGHT
6 - OXYGEN SENSOR - UPSTREAM
Fig. 128 Check Exhaust Manifold Mounting
1 - STRAIGHT EDGE
2 - CROSSOVER PIPE MOUNTING SURFACE
3 - FEELER GAUGE
RSENGINE 3.3/3.8L9 - 151
EXHAUST MANIFOLD - RIGHT (Continued)

EXHAUST SYSTEM
TABLE OF CONTENTS
page page
EXHAUST SYSTEM
DESCRIPTION..........................1
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - EXCESSIVE
EXHAUST SYSTEM NOISE...............2
DIAGNOSIS AND TESTING - EXHAUST
SYSTEM RESTRICTION CHECK...........2
INSPECTION...........................3
ADJUSTMENTS.........................3
SPECIFICATIONS
TORQUE.............................3
SPECIAL TOOLS
EXHAUST SYSTEM.....................4
CATALYTIC CONVERTER
DESCRIPTION..........................4
OPERATION............................4
REMOVAL.............................5INSPECTION...........................5
INSTALLATION..........................6
CROSS-OVER PIPE - 3.3/3.8L
REMOVAL.............................6
INSTALLATION..........................6
HEAT SHIELDS
DESCRIPTION..........................6
OPERATION............................7
REMOVAL.............................7
INSTALLATION..........................7
MUFFLER
REMOVAL.............................7
INSTALLATION..........................7
RESONATOR
REMOVAL.............................9
INSTALLATION..........................9
EXHAUST SYSTEM
DESCRIPTION
The exhaust system consists of a catalytic con-
verter, muffler, and a resonator with connecting pipes
in-between (Fig. 1). The system is serviced in two
sections; the catalytic converter and pipe, and the
muffler and resonator with connecting pipe. A band
clamp is used to connect the joint between the twocomponents. Three support hanger rods with rubber
isolators are used to support and isolate the exhaust
system. A flexible joint, integral to the catalytic con-
verter, allows for engine movement. On vehicles
equipped with AWD, an additional heat shield is
mounted to the catalytic converter. The exhaust sys-
tem is tuned for each vehicle/powertrain combination.
Fig. 1 Exhaust System - Typical (All Vehicles)
1 - CATALYTIC CONVERTER 4 - SUPPORT - RESONATOR
2 - BAND CLAMP 5 - RESONATOR
3 - SUPPORTS - MUFFLER 6 - MUFFLER
RSEXHAUST SYSTEM11-1

DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - EXCESSIVE
EXHAUST SYSTEM NOISE
CONDITION POSSIBLE CAUSES CORRECTION
EXCESSIVE EXHAUST NOISE
(UNDER HOOD)1. Exhaust manifold cracked or
broken.1. Replace manifold.
2. Manifold to cylinder head leak. 2. Tighten manifold and/or replace
gasket.
3. EGR Valve to manifold gasket
leakage.3. Tighten fasteners or replace
gasket.
4. EGR Valve to EGR tube gasket
leakage.4. Tighten fasteners or replace
gasket.
5. EGR tube to manifold tube
leakage.5. Tighten tube nut.
6. Exhaust flex-joint to manifold
leak.6. Tighten joint fasteners and/or
replace gasket.
7. Exhaust flex-joint. 7. Replace catalytic converter
assembly.
8. Pipe and shell noise from front
exhaust pipe.8. Characteristic of single wall pipe.
EXCESSIVE EXHAUST NOISE 1. Leak at exhaust pipe joints. 1. Tighten clamps at leaking joints.
2. Burned or rusted out muffler
assembly or exhaust pipe.2. Replace muffler resonator tailpipe
assembly or exhaust pipe with
catalytic converter assembly.
3. Burned or rusted out resonator. 3. Replace muffler resonator tailpipe
assembly.
4. Restriction in exhaust system. 4. Perform Exhaust System
Restriction Check. Replace
component as necessary.
5. Converter material in muffler. 5. Replace muffler and converter
assemblies. Check fuel injection and
ignition systems for proper
operation.
DIAGNOSIS AND TESTING - EXHAUST SYSTEM
RESTRICTION CHECK
Exhaust system restriction can be checked by mea-
suring back pressure using the DRB IIItand PEP
module pressure tester.
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.
NOTE: For Special Tool identification, (Refer to 11 -
EXHAUST SYSTEM - SPECIAL TOOLS).
(1) Disconnect and remove the upstream (before
catalytic converter) oxygen sensor. (Refer to 14 -
FUEL SYSTEM/FUEL INJECTION/O2 SENSOR -
REMOVAL)
(2) Install the Exhaust Back Pressure Fitting
Adaptor CH8519.
(3) Connect the Low Pressure Sensor (15 psi)
CH7063 to the back pressure fitting.
11 - 2 EXHAUST SYSTEMRS
EXHAUST SYSTEM (Continued)

(4) Following the PEP module instruction manual,
connect all required cables to the DRB IIItand PEP
module. Select the available menu options on the
DRBIIItdisplay screen for using the digital pressure
gauge function.
(5) Apply the park brake and start the engine.
(6) With transmission in Park or Neutral, raise
engine speed to 2000 RPM. Monitor the pressure
readings on the DRBIIIt. Back pressure should not
exceed specified limit. Refer to specification in table
below EXHAUST BACK PRESSURE LIMITS .
(7) If pressure exceeds maximum limits, inspect
exhaust system for restricted component. For further
catalytic converter inspection procedures, (Refer to 11
- EXHAUST SYSTEM/CATALYTIC CONVERTER -
INSPECTION). Replace component(s) as necessary.
EXHAUST BACK PRESSURE LIMITS
Exhaust Back Pressure Limit (Max)
Vehicle in Park/Neutral
(no load) @2000 RPM3.45 Kpa (0.5 psi)
INSPECTION
Inspect the exhaust pipes, catalytic converters,
muffler, and resonators for cracked joints, broken
welds and corrosion damage that would result in a
leaking exhaust system. Inspect the clamps, support
brackets, and insulators for cracks and corrosion
damage.
NOTE: Slip joint band clamps are spot welded to
exhaust system. If a band clamp must be replaced,
the spot weld must be ground off.
ADJUSTMENTS
A misaligned exhaust system is usually indicated
by a vibration, rattling noise, or binding of exhaust
system components. These noises are sometimes hard
to distinguish from other chassis noises. Inspect
exhaust system for broken, damaged or loose compo-
nents such as; clamps, heat shields, isolators, and
hanger brackets. Replace or tighten as necessary. It
is important that exhaust system clearances and
alignment be maintained.
Perform the following procedures to align the
exhaust system:
(1) Loosen band clamp at catalytic converter pipe
to muffler/resonator assembly.(2) Align the exhaust system by inserting pipe
inward or outward until specification is achieved as
shown in (Fig. 2).
(3) Tighten band clamp to 54 N´m (40 ft. lbs.).
SPECIFICATIONS
TORQUE
DESCRIPTION N´mFt.
Lbs.In.
Lbs.
Band Clamp 54 40 Ð
Cross-over PipeÐFastener 41 30 Ð
Exhaust Manifold FlangeÐFastener 37 Ð 325
Heat Shield (Muffler)ÐFastener 2.6 Ð 23
Heat Shield (Toe Board)ÐFastener 2.6 Ð 23
Heat Shield (Resonator Pipe)Ð
Fastener2.6 Ð 23
Insulator Mounting BracketÐBolts 28 Ð 250
Fig. 2 Exhaust System Alignment
1 - HANGER BRACKET TO BODY
2 - ISOLATOR
3 - HANGER - MUFFLER/RESONATOR SUPPORT
4-6mm(0.25 in.)
RSEXHAUST SYSTEM11-3
EXHAUST SYSTEM (Continued)

SPECIAL TOOLS
EXHAUST SYSTEM
CATALYTIC CONVERTER
DESCRIPTION
The toe board three-way catalytic converter is con-
nected to the exhaust manifold by the use of flex
joint and a gasket. The outlet connects to the muffler
inlet pipe and is secured with a band type clamp
(Fig. 1).
The exhaust flex-joint coupling (Fig. 3) is used to
secure the catalytic converter to the exhaust manifold.
The flex-joint has four bolts, four flag nuts and a gas-
ket that are separate parts from the exhaust flex-joint.
The flex-joint is welded to the catalytic converter.
CAUTION: When servicing, care must be exercised
not to dent or bend the bellows or bellows cover of
the flex-joint. Should this occur, the flex-joint will
eventually fail and require the catalytic converter be
replaced.
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 catalyst9punch 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 Diagnostic Information for
diagnosis of a catalyst related Diagnostic Trouble
Code (DTC).
Back Pressure Test Adapter - CH8519
Pressure Transducer CH7063
DRB III & PEP Module - OT-CH6010A
Fig. 3 Flex-joint
1 - FLANGE
2 - END CAPS
3 - CATALYTIC CONVERTER
4 - FLEXIBLE BELLOWS
11 - 4 EXHAUST SYSTEMRS
EXHAUST SYSTEM (Continued)