check engine ISUZU TF SERIES 2004 Repair Manual

6A – 28 ENGINE MECHANICAL


Cooling System Inspection
Install a radiator filler cap tester to the radiator. Apply
testing pressure to the cooling system to check for
leakage. The testing pressure must not exceed the
specified pressure.

Testing Pressure kPa(kg/cm
2 /psi)
150 (1.5/21)



Radiator Cap Inspection
The radiator filler cap is designed to maintain coolant
pressure in the cooling system at 103 kPa(1.05 kg/cm2,
15psi).
Check the radiator filler cap with a radiator filler cap tester.
The radiator filler cap must be replaced if it fails to hold the
specified pressure during the test procedure.
Radiator Cap Valve Opening Pressure
kPa(kg/cm
2 /psi)
90 – 120 (0.9 – 1.2/13 – 17)

Negative Valve (Reference) kPa(kg/cm2 /psi)
1.9 – 4.9 (0.02 – 0.05/0.28 – 0.71)
030LX003
030LX002

ENGINE MECHANICAL 6A – 29


Thermostat Operating Test
1. Completely submerge the thermostat in water.
2. Heat the water.
Stir the water constantly to avoid direct heat being
applied to the thermostat.
3. Check the thermostat initial opening temperature.
Thermostat Initial Opening Temperature C (F)
82 (180)
Oil Cooler Thermo Valve C (F)
76.5 (170)
EGR Cooler Thermo Valve C (F)
40 (104)

4. Check the thermostat full opening temperature.
Thermostat Full Opening Temperature C (F)
95 (203)
Oil Cooler Thermo Valve C (F)
90 (194)
EGR Cooler Thermo Valve C (F)
55 (131)
Valve Lift at Fully Open position mm (in)
9.5 (0.37)
Oil Cooler Thermo Valve mm (in)
4.5 (0.18)
EGR Cooler Thermo Valve mm in)
3.5 (0.14)



Drive Belt Adjustment
Check drive belts for wear or damage, and replace with
new ones as necessary. Check belts for tension, and
adjust as necessary.
1 Crankshaft damper pulley
2 Generator pulley
3 Cooling fan pulley
4 Oil pump pulley or idler pulley
5 Compressor pulley or idler pulley


030LX014
033RY00002

ENGINE MECHANICAL 6A – 31
VALVE CLEARANCE ADJUSTMENT
1. Bring the piston in either the No. 1 cylinder or the No. 4
cylinder to TDC on the compression stroke by turning
the crankshaft until the crankshaft damper pulley TDC
line is aligned with the timing pointer.

014RY00014











2. Check the rocker arm shaft bracket nuts for
looseness.
Tighten any loose rocker arm shaft bracket nuts
before adjusting the valve clearance.

Rocker Arm Shaft Bracket Nut Torque N·m (kg·m /lb·ft)
54 (5.5/40)


014RY00015
8. Check for play in the No. 1 intake and exhaust valve
push rods.
If the No. 1 cylinder intake and exhaust valve push
rods have play, the No. 1 piston is at TDC on the
compression stroke.
If the No. 1 cylinder intake and exhaust valve push
rods are depressed, the No. 4 piston is at TDC on the
compression stroke.

014RY00016
Adjust the No.1 or the No. 4 cylinder valve clearances
while their respective cylinders are at TDC on the
compression stroke.
Valve Clearance (At Cold) mm (in)
0.4 (0.016)

9. Loosen each valve clearance adjusting screw as
shown in the illustration.
10. Insert a feeler gauge of the appropriate thickness
between the rocker arm and the valve stem end.


014RY00017


11. Turn the valve clearance adjusting screw until a slight
drag can be felt on the feeler gauge.
12. Tighten the lock nut securely.
13. Rotate the crankshaft 360.
14. Realign the crankshaft damper pulley TDC notched
line with the timing pointer.
15. Adjust the clearances for the remaining valves as
shown in the illustration.

ENGINE MECHANICAL 6A – 33
INJECTION TIMING ADJUSTMENT
(4JA1T(L) only)
1. Check that the notched line on the injection pump
flange is aligned with the front plate or the timing gear
case notched line.





2. Bring the piston in the No. 1 cylinder to TDC on the
compression stroke by turning the crankshaft until the
crankshaft pulley TDC line is aligned with the timing
mark.
Note:
Check for play in the No. 1 intake and exhaust valve
push rods.
If the No. 1 cylinder intake and exhaust valve push
rods have play, the No. 1 piston is at TDC on the
compression stroke.
RTW46ASH000601
3. Disconnect the injection pipe from the injection pump
4. Remove one bolt from the distributor head.
5. Install the static timing gauge.
The probe of the gauge should be depressed inward
approximately 2 mm (0.079 in).
Static Timing Gauge: 5-8840-0145-0 (J-28827)

6. Rotate the crankshaft to bring the piston in the No. 1
cylinder to a point 30 - 40 BTDC.
7. Set the timing gauge needle to zero.
8. Move the crankshaft pulley slightly in both directions to
check that the gauge indication is stable.

6A – 34 ENGINE MECHANICAL



RTW46ASH000701
9. Turn the crankshaft clockwise and read the gauge
indication when the crankshaft pulley timing mark (8)
is aligned with the pointer.

Injection Timing : BTDC 8  2

Standard Reading mm (in)
0.5 (0.02)

If the injection timing is outside the specified range,
continue with the following steps.


10. Loosen the injection pump fixing nuts and bracket
bolts.
11. Adjust the injection pump setting angle.
When large than standard
value When smaller than standard
value
R A


A: Move the injection pump toward the engine.
R: Move the injection pump away from the engine.

ENGINE CONTROL (4JA1T(L) only)
Idling Speed Adjustment
1. Set the vehicle parking brake and chock the drive
wheels.
2. Place the transmission in neutral.
3. Start the engine and allow it to idle until the coolant
temperature reaches 70 - 80C (158 - 176F).


4. Disconnect the engine control cable from the control
lever.
5. Set a tachometer to the engine.
6. Check the engine idling speed.
If the engine idling speed is outside the specified
range, it must be adjusted.
Engine Idling Speed : 730  25 rpm


Idling Speed Adjustment
1. Loosen the idling set screw lock nut
on the injection
pump idling set bolt.
2. Adjust the idling speed to the specified range by
turning the idling set bolt
.
3. Lock the engine set nut

with the idling set bolt lock
nut.
4. Check that the idling control cable is tight (free of
slack). If required, remove the slack from the cable.

ENGINE MECHANICAL 6A – 35
Fast Idling Speed Inspection
1. Set tachometer to the engine.
2. Disconnect the vacuum hose

from the fast idle
actuator
 on the injection pump.
3. Disconnect the other vacuum hose
 from the
vacuum switching valve
 and connect it to the fast
idle actuator
.
The vacuum line will now be connected directly from
the vacuum pump
 to the fast idle actuator.
4. Check the engine fast idling speed.
If the engine idling speed is outside the specified
range, it must be adjusted.
Fast Idling Speed rpm
850  25

Fast Idling Speed Adjustment
1. Loosen the fast idle actuator bracket bolts.

2. Adjust the fast idling speed by moving the actuator
bracket, so that the clearance “S” can be 1 ~ 2 mm
(0.04 ~ 0.08 in.).
3. Tighten the bracket bolts.


Accelerator Control Cable Adjustment
Refer to Sec. 6H-6 (Accelerator Control)

ENGINE MECHANICAL 6A – 41

















































Coolant Replenishment
Warning:
When the coolant is heated to a high temperature, be
sure not to loosen or remove the rediator cap.
Otherwise you might get scalded by hot vapor or
boiling water.
To open the radiator cap, put a piece of thick cloth on
the cap and loosen the cap slowly to reduce the
pressure when the coolant has become cooler.
1. Open rediator cap pour coolant up to filler neck
2. Pour coolant into reservoir tank up to "MAX" line
3. Tighten radiator cap and start the engine. After idling
for 2 to 3 minutes, stop the engine and reopen radiator
cap. If the water level is lower, replenish.
4. After replenish the coolant tighten radiator cap, warm
up the engine at about 2000 rpm. Set heater
adjustment to the highest temperature position, and let
the coolant circulate also into heater water system.
5. Check to see the thermometer, continuously idling 5
minutes and stop the engine.
6. When the engine has been cooled, check filler neck for
water level and replenish if required. Should extreme
shortage of coolant is found, check the coolant system
and reservoir tank hose for leakage.
7. Pour coolant into the reservoir tank up to "MAX" line.

Coolant Capacity lit (US/UK gal)

4JA1 / TC 9.4 (2.5 / 2.1)
4JH1TC M/T: 10.1 (2.7 / 2.2)
A/T: 10.0 (2.6 / 2.2)

9.5 (2.5/2.1)
























Engine Warm-Up
After completing the required maintenance procedures,
start the engine and allow it to idle until it is warm.
Check the following:
1. Engine idling speed.
2. Engine noise level.
3. Engine lubricating system and cooling system.
Carefully check for oil and coolant leakage.
4. Clutch engagement.
5. Transmission operation.
6. Indicator warning light operation.

ENGINE MECHANICAL 6A – 51

10. Timing Gear Case Cover
The timing gear case is tightened together with the
injection pump at the 6 points indicated by the arrows in
the illustration.

11. Water Pump



12. Idle Gear B and shaft
Before removing the idle gear B, install bolt (M6,L=30) to
the hole marked with an arrow in the illustration to hold the
scissor gear in place.



13. Idler Gear "A"
1. Measure the camshaft timing gear backlash and the
crankshaft timing gear backlash before removing the
idler gear.
2. Measure the idler gear end play before removing the
idler gear.

NOTE:
Refer to the following items for details on the backlash
and end play measurement procedures.



Timing Gear Backlash Measurement
1. Set a dial indicator to the timing gear to measured.
Hold both the gear to be checked and the adjusting
gear stationary.
2. Move the gear to be checked as far as possible to
both the right and the left.
Take the dial indicator reading.
If the measured value exceeds the specified limit, the
timing gear must be replaced.

Timing Gear Backlash mm (in)
Standard Limit
0.10 - 0.17 (0.0039 - 0.0067) 0.30 (0.012)
020L200006
020L200020
020RY00019
020RY00020

ENGINE MECHANICAL 6A – 65
















Valve Contact Width
1. Check the valve contact faces for roughness and
unevenness. Make smooth the valve contact surfaces.
2. Measure the valve contact width.
If the measured value exceeds the specified limit, the valve
seat insert must be replaced.


Valve Contact Width mm (in)
Standard Limit
Intake 1.7 (0.067) 2.2 (0.087)
Exhaust 2.0 (0.079) 2.5 (0.078)
























Valve Seat Insert Replacement
Valve Seat Insert Removal
1. Arc weld the entire inside circumference (1) of the valve
seat insert (2).
2. Allow the valve seat insert to cool for a few minutes.
This will invite contraction and make removal of the valve
seat insert easier.
3. Use a screwdriver (3) to pry the valve seat insert free.
Take care not to damage the cylinder head (4).
4. Carefully remove carbon and other foreign material from
the cylinder head insert bore.


014RY00027
011LX039

6A – 66 ENGINE MECHANICAL


Valve Seat Insert Installation
1. Carefully place the attachment (1) (having a smaller
outside diameter than the valve seat insert) on the valve
seat insert (2).

NOTE:
The smooth side of the attachment must contact the
valve seat insert.

2. Use a bench press (3) to gradually apply pressure to the
attachment and press the valve seat insert into place.

NOTE:
Do not apply an excessive amount of pressure with
the bench press. Damage to the valve seat insert will
result.








Valve Seat Insert Correction
1. Remove the carbon from the valve seat insert surface.
2. Use a valve cutter (15
, 45
, and 75
blades) to minimize
scratches and other rough areas. This will bring the
contact width back to the standard value.
Remove only the scratches and rough areas. Do not cut
away too much. Take care not to cut away unblemished
areas of the valve seat surface.









Valve Seat Angle Degree
45
NOTE:
Use an adjustable valve cutter pilot.
Do not allow the valve cutter pilot to wobble inside the
valve guide.











3. Apply abrasive compound to the valve seat insert surface.
4. Insert the valve into the valve guide.
5. Turn the valve while tapping it to fit the valve seat insert.
6. Check that the valve contact width is correct.
7. Check that the valve seat insert surface is in contact with
the entire circumference of the valve.



011LX063 014RY00026
011LX037
011LX038