REHS9166-00

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Special Instruction
SPN 3055 FMI 1 No Start Due to Low Rail Fuel Pressure Troubleshooting for Certain
CT660 On Highway Trucks{7000}
Media Number -REHS9166-00
Publication Date -2014/05/02
Date Updated -2014/05/05
i05776971
SPN 3055 FMI 1 No Start Due to Low Rail Fuel Pressure
Troubleshooting for Certain CT660 On Highway Trucks{7000}
SMCS - 7000
On Highway Truck:
CT660 (S/N: TGA1-UP; TGD1-UP; TJD1-UP; TEJ1-UP; TRK1-UP; TKL1-UP; TEM1UP; TEP1-UP; TGR1-UP; TGS1-UP; TJS1-UP; TGT1-UP; TGW1-UP; TSW1-UP; TEY1
-UP; TSY1-UP; TEZ1-UP; TGZ1-UP)
Introduction
This Special Instruction provides the information to diagnose and troubleshoot low rail fuel pressure
on the machines listed above.
Important Safety Information
Accidental engine starting can cause injury or death to personnel
working on the equipment.
To avoid accidental engine starting, disconnect the battery cable from
the negative (−) battery terminal. Completely tape all metal surfaces of
the disconnected battery cable end in order to prevent contact with
other metal surfaces which could activate the engine electrical system.
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Place a Do Not Operate tag at the Start/Stop switch location to inform
personnel that the equipment is being worked on.
Personal injury or death can result from sudden machine movement.
Sudden movement of the machine can cause injury to persons on or
near the machine.
To prevent injury or death, make sure that the area around the
machine is clear of personnel and obstructions before operating the
machine.
Do not attempt to assemble this machine until you read and you
understand the assembly instructions.
Improper assembly procedures could result in injury or death.
Personal injury can result from hydraulic oil pressure and hot oil.
Hydraulic oil pressure can remain in the hydraulic system after the
engine has been stopped. Serious injury can be caused if this pressure is
not released before any service is done on the hydraulic system.
Make sure all of the work tools have been lowered to the ground, and
the oil is cool before removing any components or lines. Remove the oil
filler cap only when the engine is stopped, and the filler cap is cool
enough to touch with your bare hand.
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NOTICE
Care must be taken to ensure that fluids are contained during
performance of inspection, maintenance, testing, adjusting, and repair
of the product. Be prepared to collect the fluid with suitable containers
before opening any compartment or disassembling any component
containing fluids.
Refer to Special Publication, NENG2500, "Dealer Service Tool
Catalog" for tools and supplies suitable to collect and contain fluids on
Cat products.
Dispose of all fluids according to local regulations and mandates.
NOTICE
Keep all parts clean from contaminants.
Contaminants may cause rapid wear and shortened component life.
NOTICE
Contact with high pressure fuel may cause personal injury or death.
Wait 60 seconds after the engine has stopped to allow fuel pressure to
purge before any service or repair is performed on the engine fuel
lines.
Note: Cleanliness is an important factor. Before beginning the removal procedure, clean the exterior
of the components thoroughly. Cleaning the components will help to prevent dirt from entering the
internal mechanism.
Note: Put identification marks on all hoses, on all hose assemblies, on all harness assemblies, and on
all tube assemblies for installation purposes. Plug all hose assemblies and all tube assemblies in order
to prevent fluid loss, and contaminants from entering the system.
SPN 3055 FMI 1 - Low Fuel Pressure at Start
Table 1
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Condition / Description
Setting Criteria
Enable Conditions /
Values
Time
Required
Engine Speed > 70 rpm
Fuel Rail Pressure (FRP)
below minimum pressure.
Fuel Rail Pressure (FRP)
less than 10000 kPa (1450
psi)
Ambient Pressure >
83 kPa (12 psi)
0.5 seconds
Ambient Temp >
−7.04 °C (19.34 °F)
Battery Voltage (before
crank) > 11 Volts
Fault Overview
Fault code sets when the Engine Control Module (ECM) detects FRP does not build within a
predetermined time while the engine is cranking.
Malfunction Indicator Lamp (MIL) Reaction
MIL will illuminate when this fault is detected during two consecutive drive cycles.
Associated Faults
SPN 94 FMI 0 (FDP), SPN 157 FMI 3, SPN 157 FMI 4, SPN 157 FMI 20, and SPN 157 FMI 21
(FRP), and SPN 633 FMI 3, SPN 633 FMI 4, and SPN 633 FMI 5 (FPCV).
Drive Cycle to Determine Fault Status
Drive Cycle 2 in Troubleshooting, UENR5715, "2013 HD-OBD Diagnostic Reference Manual".
Possible Causes
• Fuel Rail Pressure FRP sensor or circuit fault.
• Low fuel level
• Fuel leaks
• Restricted engine mounted secondary fuel filter
• Aerated fuel delivery
• Restricted fuel supply
• Internal leak in high-pressure fuel system
• Leaking FRP relief valve
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• Leaking KUEV valve
• Failed High-pressure fuel pump
Table 2
Low Pressure Fuel System Testing
Step
1
Action
Check fuel level. Read fuel level using the
vehicle instrument panel gauge and perform a
visual inspection of fluid level in the fuel tank.
2
Using Personal Computer (PC) with engine
diagnostic software, check Diagnostic Trouble
Code (DTC) list for SPN 94 FMI 0 (FDP), SPN
157 FMI 3, SPN 157 FMI 4, SPN 157 FMI 20,
and SPN 157 FMI 21 (FRP), and SPN 633 FMI
3, SPN 633 FMI 4, and SPN 633 FMI 5
(FPCV).
Is PC DTC list free of SPN 94 FMI 0 (FDP),
SPN 157 FMI 3, SPN 157 FMI 4, SPN 157 FMI
20, and SPN 157 FMI 21 (FRP), and SPN 633
FMI 3, SPN 633 FMI 4, and SPN 633 FMI 5
(FPCV)?
3
Check that the engine cranks at a minimum of
130 rpm.
4
5
6
Verify the engine starts. Crank engine for
maximum of 20 seconds. If engine does not
start, wait 2 minutes and try again.
Does engine start and maintain idle?
Check for low Fuel Delivery Pressure (FDP).
With Fuel Pressure Gauge 372-5239 connected
at inlet to secondary fuel filter, monitor FDP
while cranking.
Does FDP measure >
207 kPa (30 psi).
Check for low FDP. Perform Fuel Delivery
Pressure (FDP) Test. Refer to Level ""Fuel
Delivery Pressure (FDP) Test" ".
Is FDP >
207 kPa (30 psi) gauge or
138 kPa (20 psi) in engine diagnostic software.
Decision
Yes: Go to Step 2.
No: Add fuel or repair leaks, and prime
engine.
Yes: Go to Step 3.
No: Repair SPN 94 FMI 0 (FDP), SPN
157 FMI 3, SPN 157 FMI 4, SPN 157
FMI 20, and SPN 157 FMI 21 (FRP),
and SPN 633 FMI 3, SPN 633 FMI 4,
and SPN 633 FMI 5 (FPCV). See health
report for link to diagnostics.
Yes: Go to Step 4.
No: Repair low cranking speed.
Yes: Go to SPN 3055 FMI 15.
No: Go to Step 5.
Yes: Go to Step 9.
No: Got to Step 6.
Yes: Repair restriction in fuel supply to
Low- Pressure Fuel Pump.
No: Go to Step 7
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7
Check for failed low-pressure fuel pump.
Perform Fuel Dead Head Test. Refer to Level
""Fuel Dead Head Test" ".
Is pressure
448 kPa (65 psi)?
8
Check for a restricted engine fuel filter. Perform
High -pressure Pump Inlet Pressure Test. Refer
to Level ""High -pressure Pump Inlet Pressure
Test" ".
Does the fuel pressure gauge read
207 kPa (30 psi)?
9
Check for aeration in low-pressure fuel system.
Perform Fuel Aeration Test. Refer to Level
""Fuel Aeration Test" ".
Is fuel system free from aeration?
10
Check for restriction in low-pressure fuel
system. Perform Fuel Restriction Test. Refer to
Level ""Fuel Restriction Test" ".
Is fuel system free of restriction?
Yes: Go to Step 8.
No: Replace High Pressure (HP) fuel
pump.
Yes: Go to Step 9.
No: Replace Engine Fuel Filter.
Yes: Go to Step 10.
No: Repair aeration in low-pressure fuel
system (according to Fuel Aeration
Test).
Yes: Go to Step 11.
No: Repair restriction in low-pressure
fuel system (according to Fuel
Restriction Test).
Table 3
High Pressure Fuel System Testing
Step
11
12
13
Action
Check for fuel return. Perform Fuel Rail Pressure (FRP) Return
Flow Test part 1. Disconnect fuel drain tube assembly at rear of
cylinder head. Connect High Pressure Return Line Tester 373-4728
-1 to cylinder head and route other end to diesel fuel container.
Crank engine for 20 seconds while monitoring fuel return from
High Pressure Return Line Tester 373-4728-1.
Is the line free of return fuel from cylinder head and rail?
Check for a failed fuel pressure relief valve. Perform Fuel Rail
Pressure (FRP) Return Flow Test part 2. Restore all fuel line
connections. Disconnect fuel rail return line at fuel rail. Connect
High Pressure Return Line Tester 373-4728-1 to fuel rail return
port and route other end to diesel fuel container. Crank engine and
monitor fuel return from High Pressure Return Line Tester 3734728-1.
Is the line free of return fuel from fuel rail?
Decision
Yes: Go to Step 12.
No: Go to Step 14.
Yes: Go to Step 13.
No: Replace fuel rail.
Yes: Replace High
Pressure (HP) fuel
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Check for a failed KUEV Valve. Complete the HP Pump Return
Flow Test. Refer to Level ""HP Pump Return Flow Test" ".
Is fuel line free of fuel from the high-pressure pump return port?
14
Check for an internal leak in the high-pressure fuel system.
Perform Fuel Rail Pressure (FRP) Leak Isolation Test. Refer to
Level ""Fuel Rail Pressure (FRP) Leak Isolation Test" ".
Is engine free of leaking injector?
pump then go to step
15.
No: Replace KUEV
valve.
Yes: Retest for SPN
3055 FMI 1 and if it
remains notify
supervisor.
No: Replace the last
capped injector and
all HP lines removed
during this test.
Yes: Retest for SPN
3055 FMI 1.
15
Run HP Pump Fuel Return Pressure Test. Refer to ""HP Pump Fuel
No: Repair restriction
Return Pressure Test" ".
in fuel return line
Is Pressure
between high 90 kPa (13 psi)?
pressure fuel pump
and fuel tank.
Note: After performing all diagnostic steps, if SPN 3055 FMI 1 remains, verify that each step was
completed correctly and the proper decision was made. Notify supervisor for further action.
Table 4
Quantity
1
Part Description
High-pressure fuel rail
Part
Number
Step
376-2724
12
High-pressure fuel rail, Replace
SRT Description
1
High-pressure fuel
pump kit
421-3155
13
High Pressure Fuel Pump & Drive
Gear, Replace
1
KUEV
435-4822
13
KUEV, Replace
5 HARD START AND NO START DIAGNOSTICS
Fuel Delivery Pressure (FDP) Test
Purpose
Verify that there is sufficient fuel pressure in low-pressure fuel system to start engine.
Tools
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• Personal Computer (PC) with engine diagnostic software
• NexIQ Usb-Link
• 372-5842 – Clean Fuel Source Tool
• 373-4730 – Air Cap, Fuel Cap, and Plug Kit
Procedure
Note: To prevent damage to engine, plug component connections immediately after each fuel line is
removed using clean fuel system caps.
Note: Ensure that fuel lines are clear of heavy debris before breaking fuel line connections.
1. With the engine OFF, disconnect fuel supply line at low-pressure fuel pump inlet.
2. Use Air Cap, Fuel Cap, and Plug Kit 373-4730 to cap disconnected fuel supply line.
Illustration 1
g03664508
Clean Fuel Source Tool connected to low-pressure fuel pump inlet
3. Connect Clean Fuel Source Tool 372-5842 to low-pressure fuel pump inlet.
4. Crank engine to remove air from fuel lines.
5. Turn ignition switch to ON, engine OFF.
6. Connect PC to vehicle's Diagnostic Connector.
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7. Start engine diagnostic software.
8. Select Hard Start - No Start session.
Illustration 2
g03664510
Hard Start - No Start session signals
9. Crank engine for 20 seconds while monitoring Fuel Delivery Pressure (FDP) signal. Record
results on Diagnostics Form.
Note: Engine diagnostic software displays Fuel Delivery Pressure (FDP) signal 103 kPa (15
psi) below actual gauge pressure.
◦ If FDP is below specification, go to Fuel Dead Head Test.
◦ If FDP builds above specification, go to Fuel Aeration Test.
Fuel Dead Head Test
Purpose
Isolate fuel pump to determine if it is able to build proper pressure.
Tools
• Compucheck fitting
• 372-5842 – Clean Fuel Source Tool
• 372-5239 – Fuel Pressure Gauge
• 373-4727 – Fuel Inlet Restriction / Aeration Tool
• 373-4734 – Fuel Block Off Tool
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Procedure
1. Retain connection between Clean Fuel Source Tool 372-5842 and low-pressure fuel pump inlet
from previous test.
2. Disconnect fuel line from low-pressure fuel pump outlet.
Illustration 3
g03664511
Fuel Inlet Restriction / Aeration Tool 373-4727 connected to low-pressure fuel pump outlet
3. Connect Fuel Inlet Restriction / Aeration Tool 373-4727 to low-pressure fuel pump outlet.
4. Use compucheck fitting to connect Fuel Pressure Gauge to Fuel Inlet Restriction / Aeration
Tool 373-4727.
5. Connect Fuel Block Off Tool to Fuel Restriction / Aeration Tool 373-4727.
6. Crank engine to remove air from fuel lines.
7. Crank engine until fuel pressure stabilizes or up to a maximum of 20 seconds.
8. Record gauge pressure on Diagnostics Form.
• If pressure is within specification, inspect secondary fuel filter, stand pipe, and housing for
defects or damage. If no defect or damage is found, go to Fuel Rail Pressure (FRP) Return Flow
Test.
• If pressure is below specification, replace fuel pump following procedures in the Engine
Service Manual. To prevent damage to a newly installed fuel pump and to verify that high back
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pressure did not cause fuel pump to fail, perform High Pressure Pump Fuel Return Pressure
Test any time fuel pump is replaced.
Note: Before installing a new fuel pump, ensure that new fuel pump is the correct replacement part.
High Pressure Pump Inlet Pressure Test
Purpose
Verify that high-pressure fuel pump is receiving fuel.
Tools
• 372-5239 – Fuel Pressure Gauge
• 373-4727 – Fuel Inlet Restriction / Aeration Tool
• 373-4734 – Fuel Block Off Tool
• 373-4735 – Fuel Line Coupler
Procedure
1. Disconnect fuel supply to AFT fuel doser module.
2. Use Fuel Line Coupler 373-4735 to connect Fuel Inlet Restriction / Aeration Tool 373-4727 to
AFT fuel doser module fuel supply line.
Illustration 4
g03664515
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Fuel Pressure Gauge connected to AFT fuel doser module fuel supply line
(1) AFT fuel doser module Fuel Supply Line
(2) Fuel Line Coupler 373-4735
(3) Fuel Inlet Restriction / Aeration Tool 373-4727
(4) Fuel Pressure Gauge 372-5239
(5) Fuel Block Off Tool 373-4734
3. Connect Fuel Block Off Tool 373-4734 to Fuel Inlet Restriction / Aeration Tool 373-4727.
4. Connect Fuel Pressure Gauge 372-5239 to Fuel Inlet Restriction / Aeration Tool 373-4727.
5. Crank engine while monitoring Fuel Pressure Gauge 372-5239. Record results on Diagnostics
Form.
• If gauge pressure is within specification, go to High-pressure Fuel Return Flow Test.
• If gauge pressure is below specification, replace secondary fuel filter and go to High-pressure
Fuel Return Flow Test.
Fuel Aeration Test
Illustration 5
g03664538
Fuel aeration test diagram
(1) Strainer / primer pump
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(2) Aeration test point 2
(3) Secondary fuel filter
(4) Fuel supply from primary fuel filter
(5) Low-pressure fuel pump
(6) Fuel Inlet Restriction / Aeration Tool 373-4727
(7) Aeration test point 1
Purpose
Check for fuel aeration.
Tools
• 372-5842 – Clean Fuel Source Tool
• 373-4727 – Fuel Inlet Restriction / Aeration Tool
• 373-4734 – Fuel Block Off Tool
• 373-4735 – Fuel Line Coupler
Procedure
Follow the below aeration test procedures.
Aeration Test Point 1
1. Remove Clean Fuel Source Tool 372-5842 from low-pressure fuel pump inlet.
2. Use Fuel Line Coupler 373-4735 to connect Fuel Inlet Restriction / Aeration Tool 373-4727
between fuel supply line to secondary fuel filter and low-pressure fuel pump outlet.
3. Prime fuel system by pumping primer pump.
4. Crank engine while visually monitoring for fuel aeration (air bubbles passing through the clean
line). Record results on Diagnostics Form.
• If fuel is not aerated, go to Fuel Restriction Test.
• If fuel is aerated, go to Aeration Test Point 2.
Aeration Test Point 2
1. Connect Clean Fuel Source Tool 372-5842 to primer pump inlet.
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2. Prime fuel system by pumping primer pump
3. Crank engine while visually monitoring for fuel aeration (air bubbles passing through the clean
line). Record results on Diagnostics Form.
• If fuel is not aerated, repair open in fuel supply line between fuel primer pump and fuel tank.
• If fuel is aerated, repair open in low-pressure fuel pump supply line or fuel primer pump.
Fuel Restriction Test
Illustration 6
g03664561
Fuel restriction test diagram
(1) Fuel restriction test point 1
(2) Strainer / primer pump
(3) Fuel restriction test point 2
(4) Fuel supply from tank
(5) Fuel restriction test point 3
(6) Primary fuel filter
(7) Low-pressure fuel pump
(8) Vacuum gauge
(9) Fuel Inlet Restriction / Aeration Tool 373-4727
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Purpose
Check for fuel supply restriction.
Tools
• Computer check fitting
• Vacuum gauge
• 372-5842 – Clean Fuel Source Tool
• 373-4727 – Fuel Inlet Restriction / Aeration Tool
• 373-4735 – Fuel Line Coupler
Procedure
Follow the below restriction test procedures.
Restriction Test Point 1
1. Use Fuel Line Coupler 373-4735 to connect Fuel Inlet Restriction / Aeration Tool 373-4727
between low-pressure fuel pump supply line and low-pressure fuel pump inlet.
2. Connect vacuum gauge to Fuel Inlet Restriction / Aeration Tool 373-4727.
3. Prime fuel system by pumping primer pump.
4. Crank engine while monitoring vacuum gauge. Record results on Diagnostics Form.
• If restriction is within specification, verify Fuel Delivery Pressure (FDP) sensor reading with
gauge.
• If restriction is above specification, go to Restriction Test Point 2
Restriction Test Point 2
1. Connect Clean Fuel Source Tool 372-5842 to primer pump inlet.
2. Prime fuel system by pumping primer pump.
3. Crank engine while monitoring vacuum gauge. Record results on Diagnostics Form.
• If restriction is within specification, go to Restriction Test Point 3.
• If restriction is above specification, repair or replace fuel strainer and primer pump assembly,
and check fuel lines.
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Restriction Test Point 3
1. Connect Clean Fuel Source Tool 372-5842 to primary fuel filter inlet.
2. Prime fuel system by pumping primer pump.
3. Crank engine while monitoring vacuum gauge. Record results on Diagnostics Form.
• If restriction is within specification, repair restriction between primary fuel filter and fuel tank.
• If restriction is above specification, replace primary fuel filter, clean fuel strainer, and check
fuel lines.
HP Pump Return Flow Test
Purpose
Verify that fuel is flowing from high-pressure return.
Tools
• Diesel fuel container
• 373-4728-1 - High Pressure Return Line Tester
Procedure
1. Connect High Pressure Return Line Tester 373-4728-1 to high-pressure fuel pump return port.
2. Route the other end of High Pressure Return Line Tester 373-4728-1 into a diesel fuel
container.
3. Crank engine for 20 seconds while monitoring fuel return from High Pressure Return Line
Tester 373-4728-1.
• If fuel is flowing from High Pressure Return Line Tester 373-4728-1, replace piston overflow
valve.
• If fuel does not flow from High Pressure Return Line Tester 373-4728-1, replace fuel pump.
Refer to the Engine Service Manual for replacement procedure and perform High Pressure
Pump Fuel Return Pressure Test to verify high back pressure did not cause fuel pump failure.
Fuel Rail Pressure (FRP) Leak Isolation
Purpose
Isolate pressure loss in high-pressure fuel system.
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Tools
• Diesel fuel container
• 373-4728-1 – High Pressure Rail Return Line Tester
• 372-5215 – High Pressure Rail Plugs
Procedure
Note: Perform this procedure only if engine does NOT START because of low or nonexistent Fuel
Rail Pressure (FRP).
1. Retain High Pressure Return Line Tester 373-4728-1 connection to cylinder head from previous
test.
Illustration 7
g03665236
High Pressure Rail Plug installed on injector six
2. Disconnect number six injector fuel line and cap off rail with High Pressure Rail Plug 3725215.
3. Crank engine while monitoring fuel leaking out of High Pressure Return Line Tester 373-47281.
• If fuel is leaking out of High Pressure Return Line Tester 373-4728-1, leave High Pressure Rail
Plug 372-5215 connected. Continue capping off one injector supply port at a time until fuel rail
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builds starting pressure. Once starting pressure is met, replace the removed injector tubes with
new parts. Verify that engine will start.
• If fuel is not leaking out of High Pressure Return Line Tester 373-4728-1 and fuel rail builds
starting pressure, replace number six injector tube and fuel pipe.
HP Pump Fuel Return Pressure Test
Purpose
Verify that return flow is within specifications.
Tools
• Compucheck fitting
• 372-5239 – Fuel Pressure Gauge
• 373-4727 – Fuel Inlet Restriction / Aeration Tool
• 373-4735 – Fuel Line Coupler
Procedure
Note: Prior to performing this test, ensure that new fuel pump is the correct replacement part.
1. Restore fuel system to normal operating condition.
2. Disconnect high-pressure fuel pump return line.
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Illustration 8
g03665238
High-pressure fuel pump return line connected to Fuel Pressure Gauge 372-5239
3. Use Fuel Line Coupler 373-4735 to connect high-pressure fuel pump return line to Fuel Inlet
Restriction / Aeration Tool 373-4727.
4. Use compucheck fitting to connect Fuel Inlet Restriction / Aeration Tool 373-4727 to Fuel
Pressure Gauge 372-5239.
5. Start engine and run high idle while monitoring Fuel Pressure Gauge 372-5239.
• If pressure is above specification, inspect fuel return line between high-pressure fuel pump and
fuel tank for restriction.
• If pressure is below specification, no further action is required.
Copyright 1993 - 2014 Caterpillar Inc.
All Rights Reserved.
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