fuel pressure SSANGYONG KORANDO 2012 User Guide

03-150000-00
(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.

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

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.
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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.

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

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.
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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

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

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

03-24
Fuel rail assembly
Relieves the pulsation.
Measures the fuel pressure.
Distributes the fuel to injectors.Camshaft position sensor
Determines the injection order.
Injector (C3I)
Pre-injection, main injection, after-injection by
signals from ECU
Fuel tank
Fuel metering by dual sender. Supply the fuel in
main fuel tank and sub fuel tank through fuel
inlet tube
2. SYSTEM LAYOUT AND OPERATION
1) Layout
Fuel supply line
Fuel return line
For sensor and actuator control logic,
refer to Chapter "ENGINE CONTROL".

03-250000-00
Crankshaft position sensor
Measuring engine rpmT-MAP sensor
Measuring booster pressure
and temperatureHFM
Measuring intake air mass and
temperature
Engine ECU (D20DTF)
Engine control by various
signals
Fuel filter assembly
Supply clean fuel/fuel
heating/water separation by
priming pumpAccelerator pedal
position sensor
Detects driver's intention for
speed up/downHigh pressure pump
Generates the high pressurized fuel
and supply it.
Plunger type HP pump (1,800
bar)
Vane type transfer pump (6bar)

03-26
2) Fuel System Flow Diagram
The fuel from the fuel tank is supplied to the fuel heater of fuel filter/priming pump and then low pressure
generated by the low pressure pump (built into HP pump) is transmitted to the HP pump.
The fuel pressure at the HP pump is controlled by the IMV valve, and the maximum allowed pressure is
1,800 bar. The compressed fuel at the fuel pump is delivered to the rail, and injected by the injectors
according to the injection signals. The injection method is the same with the conventional method; Fuel
return by backleak which operates the needle valve.
The major difference is that the fuel return line is connected to the fuel filter inlet port, not the HP pump
venturi.
The pressure from the high pressure pump is increased to 1,800 bar from 1,600 bar, and the pump is now
installed to the cylinder head (cylinder block for previous model). The fuel pressure is generated by the
operation of intake camshaft and gears. The specifications for the IMV valve and the fuel temperature
sensor are not changed.