ISUZU TF SERIES 2004 Workshop Manual

EXHAUST SYSTEM 6F – 7

GENERAL DESCRIPTION
This system controls the formation of NOx emission by recirculating the exhaust gas into the combustion chamber
through the intake manifold.

4JA1T(L):
The two EGR valves are controlled by two Vacuum Switching Valve (VSV) controlled by EGR controller according to
signals from various sensors.
The amount of EGR depends on the number of engine rotations and the opening of the accelerator.







RTW46ELF001201

6F – 8 EXHAUST SYSTEM
4JA1TC/4JH1TC
The EGR system engine is controlled by ECM. Refer to “Engine driveability and emissions” section for detail.








RTW46ELF001101

EXHAUST SYSTEM 6F – 9
EGR SYSTEM DIAGRAM 4JA1T (L)




RTW46AMF000301

EGR System Operation
Inspect EGR valve motion visually while changing engine RPM under no load condition after warming-up.
 Inspection point (Engine RPM)

RPM Idling
900  960 2000 3250
Engine Front Side VSV-1 ON ON ON OFF
Engine Rear Side VSV-2 ON OFF ON OFF

ON means VSV should receive signal to move EGR valve.
OFF means VSV shouldn’t receive signal to move EGR valve.

6F – 10 EXHAUST SYSTEM
4JA1TC/4JH1TC
The EGR system engine is controlled by ECM. Refer to “Engine driveability and
emissions” section for detail.



RTW46EMF000701

EXHAUST SYSTEM 6F – 11
INSPECTION
4JA1T(L)



Vacuum switch valve (VSV)
Use a circuit tester to measure the V.S.V. resistance.
V.S.V Resistance  at 20°C
37 ~ 44

If the resistance is not within specification, replace it.



EGR Valve
Apply vacuum to the EGR valve, check to see the valve
operation.

Negative Pressure








4JA1TC/4JH1TC




RTW46ESH000301


EVRV
Use a circuit tester to measure the EVRV resistance.
EVRV Resistance  at 20°C
14

If the resistance is not within specification, replace it.

EGR Valve
Apply vacuum to the EGR valve, check to see the valve
operation.

Negative Pressure 4JH1TC

Less than 250 mmHg Not operation
More than 300 mmHg Operation

Negative Pressure 4JA1TC

Less than 100 mmHg Not operation
More than 170 mmHg Operation
Less then 180 mmHg Not operation
More than 240 mmHg Operation

6F – 12 EXHAUST SYSTEM
EGR COOLER (4JA1TC/4JH1TC EURO-III MODEL)
REMOVAL AND INSTALLATION




RTW46EMF000201

Removal Steps
1. Bolt
2. Gasket
3. Bolt
4. Gasket
5. Bolt
6. Bolt

7. EGR Pipe Assembly
8. Gasket
9. Bolt
10. EGR Cooler Assembly
11. Gasket
12. EGR Cooler Adapter


Removal
1. Bolt
2. Gasket
3. Bolt
4. Gasket
5. Bolt
6. Bolt
7. EGR Pipe Assembly
8. Gasket
9. Bolt
10. EGR Cooler Assembly
11.Gasket
12.EGR Cooler Adapter

EXHAUST SYSTEM 6F – 13





RTW46EMF000901

Installation steps
1. EGR Cooler Adapter
2. Gasket
3. EGR Cooler Assembly
4. Gasket
5. Bolt
6. EGR Pipe Assembly
7. Bolt


8. Bolt
9. Gasket
10. EGR Valve Assembly
11. Bolt
12. EXH Manifold
13. Gasket
14. Bolt

6F – 14 EXHAUST SYSTEM
Installation
1. EGR Cooler Adapter
2. Gasket
3. EGR Cooler Assembly
4. Bolt
Tighten the bolts to the specified torque.
EGR adapter bolt torque N
m(kg
m/lb ft)
27(2.8/20)
5. Gasket
6. EGR Pipe Assembly
7. Bolt
Tighten bolts temporarily.
8. Bolt
Tighten bolts temporarily.
9. Gasket
10. Bolt
Tighten bolts temporarily.
11.Gasket
12.Bolt
Tighten bolts temporarily.
Finally tighten all bolts to the specified torque.
Confirm that there is no misalignment on the sealing
surface.
Bolt torque (Cooler-pipe) N
m(kg
m/lb ft)
27(2.8/20)
Bolt torque (Cooler-bracket) N
m (kg
m/lb ft)
24(2.4/17)
Bolt torque (Adapter-EGR valve) N
m (kg
m/lb ft)
27(2.8/20)
Bolt torque (Pipe-manifold) N
m (kg
m/lb ft)
27(2.8/20)

EXHAUST SYSTEM 6F – 15
TURBOCHARGER
MAIN DATA AND SPECIFICATIONS

Engine 4JA1T(L) 4JA1TC 4JH1TC
Model IHI RHF4H IHI RHF4H IHI RHF5
Turbine type Mixed type
Compressor type Backword & rake type
Maximum permissible speed rpm 190,000 190,000 180,000
IHI : Ishikawajima Harima Heavy Industries., Ltd.

6F – 16 EXHAUST SYSTEM
GENERAL DESCRIPTION



036LV002

The turbocharger internal mechanism consists of the turbine wheel, the compressor wheel, and the radial bearings.
These parts are supported by the bearing housing.
The turbocharger external mechanism consists of the compressor housing air intake port and the turbine housing
air exhaust port.
The turbocharger increases air intake efficiency. This results in increased engine power, reduced fuel consumption,
and minimal engine noise.
The turbocharger operates at very high speeds and temperatures. Part materials have been carefully selected and
machined to extremely high precision.
Turbocharger servicing requires great care and expertise.
If reduced performance is noted, check the engine for damage or wear. If there is no apparent engine damage or
wear, trouble with the turbocharger is indicated.