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(3) Align timing belt tensioner spring stop with
tensioner as shown (Fig. 96) and torque timing belt
tensioner retaining bolt to 34.7N´m.
(4) Rotate engine 2 complete revolution and then
recheck tensioner alignment. Readjust tensioner
alignment as necessary.
TIMING BELT/CHAIN AND
SPROCKETS
REMOVAL
CAUTION: Before removing the timing belt, the
engine must put at 90É after TDC. Failure to do so
could result in valve and/or piston damage during
reassembly. (Refer to 9 - ENGINE/VALVE TIMING -
STANDARD PROCEDURE)
(1) Disconnect negative battery cable.
(2) Remove engine cover (Refer to 9 - ENGINE -
REMOVAL).
(3) Remove air cleaner housing assembly.
(4) Support engine and remove right engine
mount.(5) Remove power steering belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(6) Remove accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL).
(7) Remove vibration damper (Refer to 9 -
ENGINE/ENGINE BLOCK/VIBRATION DAMPER -
REMOVAL).
(8) Remove timing belt outer cover (Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - REMOVAL).
(9) Loosen timing belt tensioner and remove tim-
ing belt (Fig. 97).
Fig. 96 TIMING BELT TENSIONER ALIGNMENT
1 - TENSIONER SPRING STOP
2 - TIMING BELT TENSIONER
3 - TIMING BELT TENSIONER
4 - TIMING BELT
5 - TIMING BELT INNER COVER
Fig. 97 TIMING BELT AND SPROCKETS
1 -CAMSHAFT SPROCKETS
2 - INJECTION PUMP SPROCKET
3 - INJECTION PUMP SPROCKET RETAINING NUT
4 - TIMING BELT
5 - TIMING BELT TENSIONER RETAINING BOLT
6 - TIMING BELT TENSIONER
7 - TENSIONER ALIGNMENT PIN
8 - IDLER PULLEY
9 - CAMSHAFT SPROCKET RETAINING BOLT
9a - 62 ENGINE 2.5L TURBO DIESELRG
TIMING BELT/CHAIN TENSIONER (Continued)
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INSTALLATION
(1) With both camshaft alignment pins still
installed and the engine locked at 90É after TDC.
(2) Align timing mark on injection pump sprocket
with timing mark on timing belt (Fig. 98).
(3) Install timing belt.
(4) Adjust the timing belt tensioner (Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT/CHAIN
TENSIONER & PULLEY - ADJUSTMENTS) .
(5) Remove both camshaft alignm²ent pins from
cylinder head cover/intake manifold and engine lock-
ing pin from engine block (Refer to 9 - ENGINE/
VALVE TIMING - STANDARD PROCEDURE).
(6) Install timing belt outer cover (Refer to 9 -
ENGINE/VALVE TIMING/TIMING BELT / CHAIN
COVER(S) - INSTALLATION).
(7) Install vibration damper (Refer to 9 - ENGINE/
ENGINE BLOCK/VIBRATION DAMPER - INSTAL-
LATION).
(8) Install accessory drive belt (Refer to 7 - COOL-
ING/ACCESSORY DRIVE/DRIVE BELTS - INSTAL-
LATION).
(9) Install power steering belt (Refer to 7 - COOL-
ING/ACCESSORY DRIVE/DRIVE BELTS - INSTAL-
LATION).
(10) Install right engine mount.
(11) Install air cleaner housing.
(12) Install engine cover (Refer to 9 - ENGINE -
INSTALLATION).
(13) Connect negative battery cable.
Fig. 98 INJECTION PUMP GEAR TIMING MARKS
1 - TIMING MARK ON COVER
2 - TIMING MARK ON INJECTION PUMP SPROCKET
3 - INJECTION PUMP SPROCKET
RGENGINE 2.5L TURBO DIESEL9a-63
TIMING BELT/CHAIN AND SPROCKETS (Continued)
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Page 1380 of 2321

EXHAUST SYSTEM
TABLE OF CONTENTS
page page
EXHAUST SYSTEM
DESCRIPTION............................1
OPERATION.............................1
DIAGNOSIS AND TESTING..................2
EXHAUST SYSTEM......................2
EXHAUST SYSTEM RESTRICTION CHECK....2
INSPECTION.............................3
ADJUSTMENTS...........................3
SPECIFICATIONS.........................3
CATALYTIC CONVERTER
DESCRIPTION............................4
OPERATION.............................4
REMOVAL...............................4
INSPECTION.............................5
INSTALLATION............................5CROSS-OVER PIPE
REMOVAL...............................6
INSTALLATION............................6
HEAT SHIELDS
DESCRIPTION............................6
OPERATION.............................6
REMOVAL...............................7
INSTALLATION............................7
MUFFLER
REMOVAL...............................7
INSTALLATION............................7
RESONATOR
REMOVAL...............................8
INSTALLATION............................8
EXHAUST SYSTEM
DESCRIPTION
The exhaust system consist of a catalytic converter,
muffler, and a resonator with connecting pipes in-be-
tween (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 two components.
Three support hanger rods with rubber isolators areused to support and isolate the exhaust system. A
flexible joint, integral to the catalytic converter,
allows for engine movement. On vehicles equipped
with AWD, an additional heat shield is mounted to
the catalytic converter. The exhaust system is tuned
for each vehicle/powertrain combination.
OPERATION
The exhaust system contains, quiets, and cleans
the exhaust gases generated by the engine.
Fig. 1 Exhaust System - Typical (All Vehicles)
1 - CATALYTIC CONVERTER
2 - BAND CLAMP
3 - SUPPORTS - MUFFLER
4 - SUPPORT - RESONATOR5 - RESONATOR
6 - MUFFLER
RSEXHAUST SYSTEM11-1
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DIAGNOSIS AND TESTING - EXHAUST SYSTEM
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 restriction test.
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
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.
(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.
(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 .
11 - 2 EXHAUST SYSTEMRS
EXHAUST SYSTEM (Continued)
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NOTE: For applications with dual catalytic convert-
ers, repeat test on opposite converter using the
previous steps.
(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) 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´m Ft.
Lbs.In.
Lbs.
Band Clamp 54 40 Ð
Cross-over PipeÐFastener 41 30 Ð
Exhaust Manifold FlangeÐ
Fastener37 Ð 325
Heat Shield (Muffler)ÐFastener 2.6 Ð 23
Heat Shield (Toe Board)Ð
Fastener2.6 Ð 23
Heat Shield (Resonator
Pipe)ÐFastener2.6 Ð 23
Insulator Mounting BracketÐ
Bolts28 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)
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Page 1383 of 2321

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 mani-
fold. The flex-joint has four bolts, four flag nuts and
a gasket 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 canreach 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 Powertrain Diagnostic Pro-
cedure for diagnosis of a catalyst related Diagnostic
Trouble Code (DTC).
The combustion reaction caused by the catalyst
releases additional heat in the exhaust system, caus-
ing temperature increases in the area of the reactor
under severe operating conditions. Such conditions
can exist when the engine misfires or otherwise does
not operate at peak efficiency.Do notremove spark
plug wires from plugs or by any other means short
out cylinders, if exhaust system is equipped with a
catalytic converter. Failure of the catalytic converter
can occur due to temperature increases caused by
unburned fuel passing through the converter. This
deterioration of the catalyst core can result in exces-
sively high emission levels, noise complaints, and
exhaust restrictions.
The use of catalysts also involves some non-auto-
motive problems. Unleaded gasoline must be used to
avoid poisoning the catalyst core. Do not allow engine
to operate above 1200 RPM in neutral for extended
periods over 5 minutes. This condition may result in
excessive exhaust system/floor pan temperatures
because of no air movement under the vehicle.
The flex joint allows flexing as the engine moves,
preventing breakage that could occur from the back-
and-forth motion of a transverse mounted engine.
CAUTION: Due to exterior physical similarities of
some catalytic converters with pipe assemblies,
extreme care should be taken with replacement
parts. There are internal converter differences
required in some parts of the country (particularly
vehicles built for States with strict emission
requirements) and between model years.
REMOVAL
(1) Loosen clamp and disconnect the muffler/reso-
nator assembly from catalytic converter pipe.
(2) Disconnect downstream oxygen sensor electri-
cal connector (Fig. 4). For removal of downstream
oxygen sensor, (Refer to 14 - FUEL SYSTEM/FUEL
INJECTION/O2 SENSOR - REMOVAL).
Fig. 3 Flex-joint
1 - FLANGE
2 - END CAPS
3 - CATALYTIC CONVERTER
4 - FLEXIBLE BELLOWS
11 - 4 EXHAUST SYSTEMRS
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(3) Remove catalytic converter to exhaust manifold
attaching fasteners (Fig. 5).
(4) Remove catalytic converter and gasket (Fig. 5).
INSPECTION
WARNING: THE NORMAL OPERATING TEMPERA-
TURE OF THE EXHAUST SYSTEM IS VERY HIGH.
THEREFORE, NEVER ATTEMPT TO SERVICE ANY
PART OF THE EXHAUST SYSTEM UNTIL IT IS
COOLED. SPECIAL CARE SHOULD BE TAKEN
WHEN WORKING NEAR THE CATALYTIC CON-
VERTER. THE TEMPERATURE OF THE CONVERTER
RISES TO A HIGH LEVEL AFTER A SHORT PERIOD
OF ENGINE OPERATION TIME.
Check catalytic converter for a flow restriction.
(Refer to 11 - EXHAUST SYSTEM - DIAGNOSIS
AND TESTING) Exhaust System Restriction Check
for procedure.
Visually inspect the catalytic converter element by
using a borescope or equivalent. Remove both oxygen
sensors and insert borescope. If borescope is not
available, remove converter and inspect element
using a flashlight. Inspect element for cracked or
melted substrate.
NOTE: Before replacing a catalytic converter, deter-
mine the root cause of failure. Most catalytic con-
verter failures are caused by air, fuel or ignition
problems. (Refer to Appropriate Diagnostic Informa-
tion) for test procedures.
INSTALLATION
(1) Position new gasket onto the manifold flange
and install catalytic converter (Fig. 5). Tighten fas-
teners to 37 N´m (325 in. lbs.).
NOTE: Be careful not to twist or kink the oxygen
sensor wires.
(2) Install (if removed) and connect the down-
stream oxygen sensor (Fig. 4).
(3) Install the muffler/resonator assembly. (Refer
to 11 - EXHAUST SYSTEM/MUFFLER - INSTALLA-
TION)
Fig. 4 Downstream Oxygen Sensor
1 - OXYGEN SENSOR CONNECTOR
2 - CATALYTIC CONVERTER
3 - DOWNSTREAM OXYGEN SENSOR
4 - ENGINE HARNESS CONNECTOR
Fig. 5 Catalytic Converter to Exhaust Manifold
1 - FLAG NUT
2 - GASKET
3 - BOLT
4 - CATALYTIC CONVERTER
RSEXHAUST SYSTEM11-5
CATALYTIC CONVERTER (Continued)
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