Page 1721 of 3573
QOS III PREHEATING SYSTEM 6D6 Ð 3
QOS III FLOW CHART
Page 1722 of 3573
6D6 Ð 4 QOS III PREHEATING SYSTEM
QOS III BLOCK CHART
“ST” detection“ST”
Indicator timer
11
1“ON”
“ST” “ON”13
tdDelay timer
¡C
td
¡CResetReset5
ta
Afterglow timer
Coolant temperature sensor
70¡CAll reset
12
Vehicle speed detection
9 Km/h18 Km/h
Complete combustion detection
STALLRUN
Set 8
4
9
6
10
Thermo-sensor
Speed sensor
Generator
Charge relay
Glow relay No. 1
Glow lamp
(12V, 3.4 W)
Glow relay No. 2
Glow plug
Battery 12VStarter SW
“OFF” “ST” “ACC” “ON”
: Indicator lamp light – up time
: Quick afterglow time
: Afterglow time ti
td
ta7
2
3
Dropping
register
Page 1723 of 3573

QOS III PREHEATING SYSTEM 6D6 Ð 5
Inspection on QOSIII System Operation
I Inspection on Quick Heating Operation
1. Disconnect thermo-sensor connection on the
thermostat housing.
2. Connect the circuit tester between glow plug and
engine earth.
3. Inspect the following items with starter switch set to
ON position (but do not start the engine).
1) The glow indicator shall light for about 5 sec.
2) The circuit tester shall indicate power supply
voltage for 9 ~ 13 sec.
If above specifications are not satisfied, inspect
wire harness, glow relay and thermo-sensor. If
satisfied, inspect glow plug.
II Inspection on Afterglow Operation
1. Disconnect thermo-sensor connection on the
thermostat housing.
2. Connect the circuit tester between glow plug and
engine earth.
3. Inspect the following item with start the engine.
1) The circuit tester shall indicate about 7 volts after
360 seconds of engine start.
¥ If above specifications are not satisfied, inspect
battery voltage, engine earth, wiring harness, glow
plug, dropping resistor, relay No. 2 read switch
and charge relay.
THERMO SENSOR
Measure the resistance depending on the water tempera-
ture as shown in the left figure. (Measuring range: -10¡C ~
50¡C)
Current (mA)
20 ± 1 1.0
50 ± 1Resistance (K )
1.0
2.0 ~ 3.0
0.6 ~ 1.0 Temperature
Page 1724 of 3573
6D6 Ð 6 QOS III PREHEATING SYSTEM
8 (0.8/69)
Torque N·m (Kg·m/lb·in)
23 (2.3/17)
Torque N·m (Kg·m/lb·ft)
0.8 ~ 1.0
Resistance at normal temperature
LOCTITE #262
or equivalentWhen installing the thermo sensor, apply sealant (Loctite
#262 or equivalent) to arrowed portion in the left figure to
prevent water leakage.
GLOW PLUG
Inspect the resistance
No Continuity 2 –4
Continuity 1 –3
Continuity 2 –4
Continuity 1 –2
No Continuity 1 –3
Continuity 4 –5
No Continuity 1 –2
Continuity 1 –3
224 ~ 236
Resistance of normal ambient temperature m
DROPPING RESISTOR
Inspect the resistance
GLOW PLUG RELAY
Inspect the continuity
If apply the battery voltage to terminal between 1 - 3
CHARGE RELAY
Inspect the continuity
If apply the battery voltage to terminal between 4 - 5
Page 1725 of 3573

ENGINE EXHAUST 6F Ð 1
SECTION 6F
ENGINE EXHAUST
CAUTION:
overheating of the floor pan and possible damage
to the passenger compartment, insulation and trim
materials. Exhaust system components must have enough
clearance from the underbody to prevent
CONTENTS
PAGE
General Description ........................................................................................................ 6F-2
Hangers ........................................................................................................................6F-2
Gasket .......................................................................................................................... 6F-2
On-Vehicle Service .......................................................................................................... 6F-3
Front Exhaust Pipe ...................................................................................................... 6F-3
Center Exhaust Pipe .................................................................................................... 6F-5
Exhaust Silencer .......................................................................................................... 6F-7
Rear Exhaust Pipe ....................................................................................................... 6F-9
Page 1726 of 3573

6F Ð 2 ENGINE EXHAUST
GENERAL DESCRIPTION
150RV013
When inspecting or replacing exhaust system
components, make sure there is adequate clearance from
all points on the underbody to prevent overheating of the
floor pan and possible damage to the passenger
compartment insulation and trim materials.
Check complete exhaust system and nearby body areas
and rear compartment lid for broken, damaged, missing
or mispositioned parts, open seams, holes, loose
connections or other deterioration which could permit
exhaust fumes to seep into the rear compartment or
passenger compartment. Dust or water in the rear
compartment may be an indication of a problem in one of
these areas. Any faulty areas should be corrected
immediately.
HANGERS
Various types of hangers are used to support exhaust
system(s). These include conventional rubber straps,
rubber rings, and rubber blocks.
The installation of exhaust system supports is very
important, as improperly installed supports can cause
annoying vibrations which can be difficult to diagnose.
GASKET
The gasket must be replaced whenever a new exhaust
pipe, muffler or exhaust throttle is installed.
Page 1727 of 3573
ENGINE EXHAUST 6F Ð 3
ON-VEHICLE SERVICE
Rattles and noise vibrations in the exhaust system
are usually caused by misalignment of parts. When
aligning the system, leave all bolts or nuts loose
until all parts are properly aligned; then tighten,
working from front to rear.
1. Check connections for looseness or damage,
especially for exhaust gas leakage.2. Check clamps and rubbers for weakness, cracks
or damage.
3. If any part of the converter heat shield is
damaged or dented to the extent that it contacts
the catalyst, repair or replace.
4. Check for dents or damage and for any holes or
cracks caused by corrosion.
REMOVAL
Preparation:
¥ Disconnect battery negative cable.
¥ Raise the vehicle and support with suitable safety
stands.
1. Front exhaust pipe mounting bracket fixing
bolt
150RV009
FRONT EXHAUST PIPE
4JG2-NA
4JG2-T3
31
4
42
Page 1728 of 3573
6F Ð 4 ENGINE EXHAUST
2. Front exhaust pipe fixing nuts
¥ Remove two bolts fixed from front pipe and center
pipe A.
3. Exhaust manifold fixing nuts
¥ Remove two fixing nuts from exhaust manifold and
front pipe.
4. Front exhaust pipe
INSTALLATION
4. Front exhaust pipe
3. Exhaust manifold fixing nuts
¥ Tighten the fixing nuts to the specified torque.
67 (6.8/49)N·m (Kg·m/lb·ft)
2. Front exhaust pipe fixing nuts
¥ Tighten the fixing nuts to the specified torque
43 (4.4/32)N·m (Kg·m/lb·ft)
1. Front exhaust pipe mounting bracket fixing
bolt
¥ Tighten the fixing nuts to the specified torque
40 (4.1/30)N·m (Kg·m/lb·ft)