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1.Insert the special tool
nozzle gasket remover (MB992333) to the fuel injector
mounting hole on the cylinder head.
2.Rotate the
dial of the tool as shown, and then pull out the tool while
holding the fuel injector nozzle gasket.
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1.Clean the fuel injector
assembly (nozzle) and the cylinder head (fuel injector
insertion hole) by following the procedure below.
(1)
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| caution |
Do not clean the
injection part of the nozzle with a
resin spatula.
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Using a resin spatula, scrape off the carbon deposit
on the fuel injector nozzle side face ("A" shown in the
figure).
(2)
Spray the carburettor cleaner (MZ100139) or equivalent to
the nozzle side face ("A" shown in the figure).
(3)
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| caution |
Do not touch the
injection part of the nozzle with
hand or wipe it with a rag.
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Leave the injection part for a while until the
carbon deposit melts down, and then blow air to the
injection part.
(4)
Insert the special tool ornament remover (MB990784) to the
cylinder head (fuel injector insertion hole) with turning
the special tool as shown, and scrape off the carbon
deposit.
(5)
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| caution |
In order to
prevent carbon from adhering to the
inner surface of the cylinder, blow
air with the piston in the TDC
position.
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Remove the special tool MB990784, and blow off the
carbon deposit on the cylinder head (fuel injector insertion
hole) by air.
(6)
Check that there is no carbon deposit remaining on the
contact surface of the fuel injector nozzle
gasket.
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| note |
Repeat Step 4 to
Step 6 several times until the
carbon deposit is completely
removed.
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2.Replace the fuel injector nozzle gasket
with a new one.
3.
| caution |
- If the removed fuel injector assembly to
be reinstalled cannot be identified,
register the injector identification
code and perform the small injection
quantity learning. (Refer to GROUP 00
- Precautions before Service, What
the Common Rail Engine Learns
 ).
- Securely insert the fuel injector
assembly.
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Install the fuel injector
assembly.
4.Apply an adequate and minimum amount
of engine oil to the thread of the fuel injector holder
mounting bolts, the lower area of the flange, and fuel
injector washer.
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5.Insert the fuel injectors
holder along the injector connectors and secure it by
twisting by 90 °, and let both right and left sides of
the fuel injector holder mounting bolts be seated at the
same time. Make sure that the fuel injector holder is placed
within 2 mm in the horizontal axis by using a L-shaped steel
scale.
6.Mount the fuel injection pipe No. 1 to
No. 4 and temporarily install them.
7.Tighten the
bolt on the engine front side of the fuel injector holder
mounting bolts to 1.1 ± 0.1 N·m.
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8.Use the special tool angle
gauge (MB991614) to tighten the engine rear side bolts of
the fuel injector holder to 180° ±
1°.
9.Use the special tool (MB991614) to
tighten the engine front side bolts of the fuel injector
holder to 90° ± 1°.
10.
| caution |
- The removed fuel injection pipe can be
reassembled up to five times. To count
the number of fuel injection pipe
reassembly, record it by adding the
reassembly number of this time (once
usually) to the previous number of
reassembly written on the maintenance
handbook. When the number of the
previous reassembly reaches 5 or when
the fuel injector assembly or common
rail assembly is replaced, always use a
new fuel injection pipe. At that time,
write "New (0 times)" in the maintenance
handbook.
- If a fuel leak is present in the fuel
injection pipe and fuel injection pipe
set once, do not reuse it and replace
with a new one.
- If the fuel injector assembly, common
rail assembly or supply pump assembly is
replaced, the contact surface (seal
surface) between the fuel injection pipe
and fuel injection pipe set, and the
other side component is changed, do not
reuse the fuel injection pipe and fuel
supply pump pipe and replace with a new
one.
- When reassembling the fuel injection
pipe, remove the foreign material
attached on the sealing surface, and
install it with the contacting point of
the pipe aligned.
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Loosen the install bolt of the common rail assembly,
and the flare nut of the supply pump pipe. (Refer to .)
11.Align
the fuel injection pipe centre axis with the other side
components (common rail assembly and fuel injector assembly)
centre axis to install the fuel injection pipe No.1 to No.4.
Then, tighten the flare nut temporarily until the tip of
pipe (seal surface) contacts with the other side components.
| note |
When the fuel injection pipe
is installed, tighten the flare nut while
shaking the pipe lightly to align the centre
axis of both components.
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12.Using the special tool
crowfoot wrench (MB992211), tighten the common rail assembly
side of the fuel injection pipe No.1 to No.4 to the
temporary tightening torque calculated by the following
formula.
Tightening torque: (18 ± 2)
× {L ÷ (L + 25)} N·m
18 ± 2: Tightening torque of
the fuel injection pipe (unit: N·m)
L:
Distance between the centre of a torque wrench drive
and of its handle (unit: mm)
25: Length of pitch
for special tool between holes (unit:
mm)
13.Using the special tool
crow foot wrench (MB992211), tighten the common rail
assembly side of the fuel injection pipe No.1 to No.4 to the
specified torque calculated by the following
formula.
Tightening torque: (35 ± 5)
× {L ÷ (L + 25)} N·m
35 ± 5: Tightening torque of
the fuel injection pipe (unit: N·m)
L:
Distance between the centre of a torque wrench drive
and of its handle (unit: mm)
25: Length of pitch
for special tool between holes (unit:
mm)
14.Tighten the install bolt
of the common rail assembly, and the flare nut of the supply
pump pipe. (Refer to .)
15.Check
that no fuel is leaked from the fuel injection pipe
connection area and the gasket.
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