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03-16
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 for 5 seconds.
Check the flow volume of injector backleak. 4.
5.
If the value is out of the specified range,
replace the injector.
Flow volume of injector
backleakbelow 20 cm
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03-170000-00
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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03-18
Pressure leak test in fuel system with scan tool ▶
When the dynamic test for injector backleak is performed, this test should be done together with it.
However, you can check the pressure leak from the fuel system only with this test.
<007b00960047008b00960047009b008f0090009a0047009b008c009a009b00530047009b008f008c0047008a00960096009300880095009b0047009b008c00940097008c00990088009b009c0099008c0047009a008f0096009c0093008b00470089008c00
470096009d008c00990047005d0057020b006a00550047006a>heck the conditions of sensors
and components in fuel system with scan tool.
Perform the diagnostic test as follows: 1.
2.
3.
Select the "Vehicle Model" and go to "Diagnosis Mode".
Select "Pressure Leak Test in Fuel System" in "Diagnosis Menu".
If the conditions are OK, press "Start". -
-
-
The pressure leak test procedure is performed in 4 cycles. The engine speed goes up to
3,500 rpm and down again four times for 18 seconds. If the system is OK, the "System OK"
message will be displayed.
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03-190000-00
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 range. 5.
6.
7.
Specification1,050 bar or more
Page 155 of 1082
03-20
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.
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03-210000-00
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 1,600 bar.
<007a00960094008c0047008a00960094009700960095008c0095009b009a0047009000950047009000950091008c008a009b00960099004700880095008b0047006f007700470097009c00940097004700880099008c004700940088008a008f0090009500
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
Page 157 of 1082
03-22
(2) Di engine and its expected problems and remedies can be caused by
water in fuel
System supplement against paraffin separation ▶
In case of Diesel fuel, paraffin, one of the elements, can be separated from fuel during winter and then
can stick on the fuel filter blocking fuel flow and causing difficult starting finally. Oil companies supply
summer fuel and winter fuel by differentiating mixing ratio of kerosene and other elements by region and
season. However, above phenomenon can be happened if stations have poor facilities or sell improper
fuel for the season. In case of DI engine, purity of fuel is very important factor to keep internal
preciseness of HP pump and injector.
Accordingly, more dense mesh than conventional fuel filter is used. To prevent fuel filter internal clogging
due to paraffin separation, SYMC is using fuel line that high pressure and temperature fuel injected by
injector returns through fuel filter to have an effect of built-in heater (see fuel system).
System supplement and remedy against water in fuel ▶
As mentioned above, some gas stations supply fuel with excessive than specified water. In the
conventional IDI engine, excessive water in the fuel only causes dropping engine power or engine
hunting. However, fuel system in the DI engine consists of precise components so water in the fuel can
cause malfunctions of HP pump due to poor lubrication of pump caused by poor coating film during high
speed pumping and bacterization (under long period parking). To prevent problems can be caused by
excessive water in fuel, water separator is installed inside of fuel filter. When fuel is passing filter, water
that has relatively bigger specific gravity is accumulated on the bottom of the filter.
Water drain from water separator ▶
If water in the separator on the fuel filter exceeds a certain level, it will be supplied to HP pump with fuel,
so the engine ECU turns on warning lamp on the meter cluster and buzzer if water level is higher than a
certain level.
Due to engine layout, a customer cannot easily drain water from fuel filter directly, so if a customer
checks in to change engine oil, be sure to perform water drain from fuel filter.
Water separator
Page 158 of 1082
03-230000-00
ENGINE CONTROL
SYSTEM
Engine ECU (D20DTF)
1. OVERVIEW
The components in the fuel system supply fuel and generate high pressure to inject fuel to each injector.
They are controlled by the engine ECU.
The common rail fuel injection system consists of fuel tank, fuel line, low pressure line which supplies lo
w
pressure fuel to the low pressure pump (includes high pressure pump), high pressure line which
connected to the injector and the engine control unit (ECU) which calculates the accelerator pedal
position and controls the overall performance of vehicle based on the input signals from various sensors.
HP fuel pump
Common rail and
Injector Fuel filter
(Priming pump)
Fuel supply tube
Fuel return tube
Fuel tank Fuel neck
Fuel sender (main)
Fuel sender (sub)
Low pressure line
High pressure line
