WARNING: HIGH-PRESSURE FUEL LINES DELIVER DIESEL FUEL UNDER EXTREME PRESSURE FROM THE INJECTION PUMP TO THE FUEL INJECTORS. THIS MAY BE AS HIGH AS 23,200 PSI (1600 BAR). USE EXTREME CAUTION WHEN INSPECTING FOR HIGH-PRESSURE FUEL LEAKS.

WARNING: FUEL UNDER THIS AMOUNT OF PRESSURE CAN PENETRATE SKIN CAUSING PERSONAL INJURY OR DEATH. INSPECT FOR HIGH-PRESSURE FUEL LEAKS WITH A SHEET OF CARDBOARD. WEAR SAFETY GOGGLES AND ADEQUATE PROTECTIVE CLOTHING WHEN SERVICING FUEL SYSTEM.

Turn the ignition on.
With the scan tool, read the ECM DTCs.

Are there any DTCs present?

Yes

Refer to symptom list for problems related to this DTC.

Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).

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2. CHECKING BOOST PRESSURE

NOTE: This test requires two people. One person to test drive the vehicle while a technician observes the scan tool readings

With the scan tool, read and compare the Boost Pressure (PSI) with the Boost Pressure Desired/Setpoint (PSI) while test driving the vehicle under various load conditions such as idle, hard acceleration, cruise and deceleration.

NOTE: The Boost Pressure reading should directionally follow (trail) the Boost Pressure Desired/Setpoint reading.

Does the Boost Pressure reading follow the Boost Pressure Desired/Setpoint reading?

Yes

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3. CHECK POWER AND GROUNDS

Refer to the symptom list and perform the Checking the ECM Power and Ground test.

Were any problem found with the ECM powers and grounds?

Yes

Repair as necessary.

Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).

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4. CHECKING FUEL PRESSURE

NOTE: This test requires two people. One person to test drive the vehicle while a technician observes the scan tool readings

With the scan tool, read and compare the Fuel Pressure (PSI) with the Fuel Pressure Desired/Setpoint (PSI) while test driving the vehicle under various load conditions such as idle, hard acceleration, cruise and deceleration.

NOTE: The Fuel Pressure reading should follow (trail) closely to the Fuel Pressure Desired/Setpoint reading.

Does the Fuel Pressure reading follow closely to the Fuel Pressure Desired/Setpoint reading?

Yes

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5. SCAN TOOL TESTS

With the scan tool, select Engine, System Tests and perform the following tests:
- Injector Fuel Correction Test.
- Cylinder Balance test.
- Compression Test.

Were any problems found?

Yes

Diagnose and/or repair as necessary.

Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).

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6. FUEL SYSTEM CONTAMINATION

NOTE: Mixing any other fuels such as gasoline or kerosine can cause this symptom to occur.

Turn the ignition off.

Inspect the fuel system for contamination.

Is the fuel contaminated?

Yes

Repair as necessary in accordance with the Service Information.

Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).

Test Complete.

7. FUEL SYSTEM LEAK

Inspect the entire fuel system for leakage.

Is there any evidence of leakage?

Yes

Repair as necessary in accordance with the Service Information.

Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).

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8. CHECKING FUEL DELIVERY SYSTEM

Refer to the appropriate Service Information and refer to Diagnosis and Testing Fuel Delivery System table.

NOTE: The following is a list of problems that can cause fuel pressure to deviate from specification: restricted fuel filter or fuel lines, failed fuel pressure solenoid, air in fuel system, failed fuel sending unit, contaminated fuel, faulty injector.

Were there any problems with the Fuel Delivery System?

Yes

Repair as necessary in accordance with the Service Information.

Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).

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9. CHECKING FOR AIR IN FUEL SYSTEM

Start the engine.
With the scan tool, compare the Fuel Pressure Setpoint with the Actual Fuel Pressure readings.

NOTE: If there is air in the fuel system, the Actual Fuel Pressure will oscillate more than 100 spi above and/or below the Fuel Pressure Setpoint.

Does Actual Fuel Pressure oscillate more than 100 psi above and/or below the Fuel Pressure Setpoint?

Yes

Refer to the Service Information to purge air from the fuel system.

Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).

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10. FUEL PRESSURE SOLENOID

Start the engine.
With the scan tool, compare the Fuel Pressure Setpoint with the Actual Fuel Pressure readings.

NOTE: A sticking Fuel Pressure Solenoid is indicated by Actual Fuel Pressure gradually dropping below the Fuel Pressure Setpoint then suddenly increasing (spiking) above the Fuel Pressure Setpoint.

Does Actual Fuel Pressure gradually decrease then suddenly increase (spike) above the Fuel Pressure

Yes

Replace the Fuel Pressure Solenoid in accordance with the Service Information.

Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).

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11. FUEL INJECTOR(S)

NOTE: An injector that sticks open can cause this symptom. A sticking injector will cause the engine to miss fire and emit excessive black smoke from the exhaust system.

Start and idle the engine.

Does the engine exhibit the symptoms described in the above note?

Yes

Using the Service Information, remove and inspect the Fuel Injectors for signs of damage or debris that may cause the injector to stick. Sticking injectors may cause the combustion chamber to become black and oil soaked. Replace Injector(s) as necessary.

Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).

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12. ENGINE DRIVE BELT/CHAIN

Refer to the Service Information to ensure the Engine Drive Belt/Chain is installed correctly and the camshaft and crankshaft gears are timed correctly.

Were any problems found?

Yes

Repair as necessary.

Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).

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13. FUEL PRESSURE SOLENOID

Turn the ignition off.
Replace the Fuel Pressure Solenoid in accordance with the Service Information.
Turn the ignition on.
With the scan tool, erase the ECM DTCs.
Attempt to start and test drive the vehicle.
With the scan tool, read the ECM DTCs.

Does the ECM display this DTC?

Yes

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Test Complete.

14. FUEL QUANTITY SOLENOID

Turn the ignition off.
Replace the Fuel Quantity Solenoid in accordance with the Service Information.
Turn the ignition on.
With the scan tool, erase the ECM DTCs.
Attempt to start and test drive the vehicle.
With the scan tool, read the ECM DTCs.

Did this DTC set again?

Yes

Replace the Fuel Pump in accordance with the Service Information.

Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).

Test Complete.

15. CHECKING FOR AIR LEAKS

NOTE: Inspect all air intake and turbocharger related tubes for damage, restriction or poor connection. Any of these conditions can cause a poor performance/lack of power symptom.

Turn the ignition off.
Remove the Inlet Pressure Sensor.
Connect smoke machine 84-04 to the Inlet Pressure Sensor port in the intake duct and begin injecting smoke into the intake system.
Observe all intake system components for evidence of smoke leakage.

Is there evidence of smoke leakage?

Yes

Repair or replace as necessary.

Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).

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16. BOOST CONTROL VACUUM SUPPLY

Refer to symptom Checking The Boost Control Vacuum Supply in the Driveability category.

Is the boost control vacuum supply system o.k.?

Yes

Using the Service Information, replace the Turbocharger assembly.

Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).

Repair boost system vacuum supply as necessary.
Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).