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03-12
(5) High Pressure System Pressure Test
Fuel rail pressure test ▶
Disconnect the fuel rail pressure sensor
connector and then IMV connector. 1.
Connect the pressure tester to the fuel rail
pressure sensor connector. 2.
Crank the engine 2 times for 5 seconds. 3.
Read the highest pressure value displayed
on the tester display.
If the highest pressure value is 1,050 bar or
less, refer to the section "Fuel System
Check Process". -
-
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03-132210-01
How To Use Pressure Tester ▶
Press the "TEST" button on the tester to
check if the message "TEST?" is displayed.
If the button is pressed again at 4 seconds
after starting engine cranking, the highest
pressure is displayed on the tester. 1.
2.
The fuel rail pressure value can be checked using a diagnostic device.
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03-14
(6) Low Pressure System Pressure Test
Inspection procedure ▶
All wirings/connectors and fuel lines should be
connected and the engine should work
properly.
Prepare a special tool for low pressure test
and clean it thoroughly to prevent foreign
materials from entering. 1.
2.
Disconnect the key connector for fuel filter connection, and connect both connectors to the fuel filter
and hose. 3.
Start the engine and check visually for clogged low pressure fuel system, excessive air or air entry.
If the fuel flow is not sufficient or air is in the fuel, repair the leak area. 4.
5.
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03-152210-01
Static test for backleak of injector ▶
Disconnect the injector return hose and cover
the openings with caps shaped screw (included
in the special tool). 1.
Connect the hose of the container for
measuring backleak to the return nipple of the
injector.
(prevent air entry to the low pressure line) 2.
Disconnect the IMV connector of the high
pressure pump and then fuel pressure
sensor connector. 3.
The connector of the injector can be easily
contaminated. Always keep it clean.
Crank the engine 2 times for 5 seconds.
Check the time for flow if injector backleak and
confirm that it is within the specified range. 4.
5.
If the value is out of the specified range,
replace the injector.
SpecificationBelow 20 sec.
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03-16
Dynamic test for backleak of injector ▶
Warm up the engine so that the engine
coolant temperature be over 80℃ and star
the engine again.
Disconnect the injector return hose and cover
the openings with caps shaped screw
(included in the special tool).. 1.
2.
Connect the hose of the container for
measuring backleak to the return nipple of the
injector.
Start the engine again and let the engine idle
for 30 seconds.
Perform backleak test of fuel system with a
diagnostic device after 30 seconds. 3.
4.
5.
This test consists of 4 cycles, and the engine rpm
reaches 3,500 rpm for 18 seconds in each cycle.
Check the amount of backleak collected into
the container and confirm that it is within the
specified range. 6.
Specification38 ml or less
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03-172210-01
HP pump pressure test ▶
Prepare a special tool for high pressure test
and clean it thoroughly to prevent foreign
materials from entering. 1.
Disconnect the high pressure fuel supply pipe
on the HP pump and install the close rail in the
tool kit. 2.
Connect the other end of the close rail to the
fuel rail for test. 3.
Disconnect the return hose for HP pump and
connect the clear hose and connect its the
other end to the return port of the fuel rail for
test. 4.
Connect the digital tester connector to the
sensor connector of the fuel rail for test.
Crank the engine 2 times for 5 seconds after
removing the IMV connector and fuel rail
pressure sensor connector.
Read the pressure value displayed on the
tester display is within the specified 5.
6.
7.
Specification1,050 bar or more
Page 95 of 751

03-18
3. CAUTIONS FOR DI ENGINE
1) Cautions for DI Engine
This chapter describes the cautions for DI engine equipped vehicle. This includes the water separation
from engine, warning lights, symptoms when engine malfunctioning, causes and actions.
DI Engine 1.
Comparatively conventional diesel engines, DI engine controls the fuel injection and timing electrically,
delivers high power and reduces less emission..
System Safety Mode 2.
When a severe failure has been occurred in a vehicle, the system safety mode is activated to protect the
system. It reduces the driving force, restricts the engine speed (rpm) and stops engine operation. Refer
to "Diagnosis" section in this manual.
Engine CHECK Warning Lamp 3.
The Engine CHECK warning lamp on the instrument cluster comes on when the fuel or
major electronic systems of the engine are not working properly. As a result, the
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8800a00047009a009b0088009300930055>
Water Separator Warning Lamp 4.
When the water level inside water separator in fuel filter exceeds a certain level (approx.
45 cc), this warning light comes on and buzzer sounds.
Also, the driving force of the vehicle decreases (torque reduction). If these conditions
occur, immediately drain the water from fuel filter.
Page 96 of 751

03-192210-01
2) Cleanness
(1) Cleanness of DI engine fuel system
Cleanness of DI engine fuel system and service procedures ▶
The fuel system for DI engine consists of transfer (low pressure) line and high pressure line.
Its highest pressure reaches over 1,800 bar.
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8c008b00470088009b0047009b008f008c004700940090008a>rometer 100 μm of
preciseness.
The pressure regulation and injector operation are done by electric source from engine ECU.
Accordingly, if the internal valve is stuck due to foreign materials, injector remains open.
Even in this case, the HP pump still operates to supply high pressurized fuel. This increases the
pressure to combustion chamber (over 250 bar) and may cause fatal damage to engine.
You can compare the thickness of injector nozzle hole and hair as shown in below figure (left side). The
below figure shows the clearance between internal operating elements.
The core elements of fuel system has very high preciseness that is easily affected by dust or very small
foreign material. Therefore, make sure to keep the preliminary works and job procedures in next pages.
If not, lots of system problems and claims may arise.
Hair
Nozzle holeValve actuator lift - 0.028 mm
Diameter
0.04 mm
Operating
clearance
0.002 mm
Diameter
2.0 mm