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2) Diagnostic Test for Engine Fuel System
(1) Overview
If a DTC is displayed on the diagnostic device, check the low pressure- and high pressure fuel
systems before removing the components.
To run the system properly, the electric system must be intact but for the DI engine, the fuel
pressure should be measured also when there is a malfunction even after the diagnostic test with
a diagnostic device.
(2) Hydraulic system
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03-8
(4) Loss of pump pressure/flow
Loss of HP pump pressure/flow ▶
Faulty fuel supply line, or damaged or worn pump causes the lack of flow pressure and flow
volume
Example: ▶
Air in fuel supply line
Excessive load on fuel supply line (←400 mBar)
Burned out and mechanical worn pump
High temperature of fuel supply (> 85℃) -
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03-92210-01
Device for high pressure
Device for low pressure
3) DI Engine Fuel System Pressure Test
(1) Test device (Tool kit)
(2) Pre-check
Check-tighten fuel supply line
Check fuel level in fuel tank
Check air in fuel supply line (bubble in fuel supply line or fuel)
Check fuel supply line for leaks (low pressure and high pressure)
Check that specified fuel is used
Check fuel filter for contamination -
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03-10
(3) DI Engine Fuel System Check Procedure
If several DTCs are output simultaneously, check the electric wiring for open or short circuit.
Check the low pressure fuel system and fuel filter and confirm that there are no abnormalities.
Carry out the high pressure fuel system check.
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(5) High Pressure System Pressure Test
Fuel rail pressure test ▶
Disconnect the pressure sensor connector
(A) and IMV connector (B) from the fuel
rail. 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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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.