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03-4
2. MAINTENANCE AND INSPECTION
1) Maintenance Procedures for DI Engine Fuel System
Always keep the workshop and lift clean (especially, from dust).
Always keep the tools clean (from oil or foreign materials).
Wear a clean vinyl apron to prevent the fuzz, dust and foreign materials from getting into fuel system.
Wash your hands and do not wear working gloves. 1.
2.
3.
Follow the below procedures before starting service works for fuel system.
If the problem is from HP pump, fuel supply line or injector, prepare the clean special tools and sealing
caps to perform the diagnosis for DI engine fuel system in this manual. At this point, thoroughly clean
the related area in engine compartment. 4.
Clean the engine compartment before starting service works.
Tool kit for high pressure lineTook kit for low pressure line
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Follow the job procedures. If you find a defective component, replace it with new one. 5.
Once disconnected, the fuel pipes between HP pump and fuel rail and between fuel rail and each
injector should be replaced with new ones. The pipes should be tightened tospecified tightening torques
during installation. Over or under torques out of specified range may cause damages and leaks at
connections. Once installed, the pipes have been deformed according to the force during installation,
therefore they are not reusable. The copper washer on injector should be replaced with new one. The
injector holder bolt should be tightened to specified tightening torque as well. If not, the injection point
may be deviated from correct position, and it may cause engine disorder.
Plug the removed components with clean and undamaged sealing caps and store it into the box to
keep the conditions when it was installed. 6.
To supply the fuel to transfer line of HP pump
press the priming pump until it becomes
hard. 7.
Priming pump
Priming pump cap
Fuel filter assembly
Check the installed components again and connect the negative battery cable. Start the engine and
check the operating status.
With Scan Tool, check if there are current faults and erase the history faults. 8.
9.
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03-6
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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(3) Excessive backleak of injector
Excessive injector backleak ▶
Occurs when the injector control valve is not sealed due to the entry of the foreign materials.
Example: ▶
Entry of foreign materials
Burned out and worn HP pump
Mechanical damage inside the injector -
-
-
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(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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3) DI Engine Fuel System Pressure Test
(1) Test device (Tool kit)
Device for high pressure
Device for low pressure
(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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(4) Fuel System Check Procedure