Service Procedure
Service ProcedureImportant
All replaced injectors must be returned to either the WPC or the core return center (UPS-SCS). Approximately 30% of the warranty claims will be requested back to the WPC. Export dealers will not utilize this process.
Important
WAIT UNTIL THE WARRANTY CLAIM IS PAID TO DETERMINE THE LOCATION TO WHICH THE INJECTORS MUST BE RETURNED. IF A WPC PART RETURN REQUEST IS RECEIVED, RETURN THE INJECTORS TO THE WPC. IF A WPC PART RETURN REQUEST IS NOT RECEIVED, THEN RETURN THE INJECTORS TO THE CORE RETURN CENTER. Please follow Corporate Bulletin Number 99-00-89-019E that applies to the WPC return procedures. All injectors of a single engine must arrive at the WPC boxed or bagged together in sets of four or eight injectors. A copy of the part request, repair order with technician comments, snapshot of the preliminary (actual) fuel rail pressure vs. desired as commanded by the Tech 2(R) to 160 MPa, and the completed diagnostic worksheet must be included with the injectors. The WPC will be verifying sets of injectors for high flow rates. Injectors returned without the required documentation included and/or not having high flow rates will be susceptible to feedbacks and possible debt. No snapshot is required for vehicles that do not start.
SAMPLE
SAMPLE
1. Command the fuel rail pressure with the Tech 2(R) to 160 MPa at idle. Take a snapshot of the actual vs. the desired fuel rail pressure. A copy of this snapshot must accompany the injectors returned to the Warranty Parts Center (WPC). No snapshot is required for vehicles that do not start.
2. If the actual pressure does not reach 158 Mpa, then further diagnosis to determine the cause must be completed.
Reference the table below in order to follow current SI diagnostics for the condition that the vehicle is experiencing.
• If the diagnostics lead to Fuel System Diagnosis - High Pressure Side, then follow those diagnostic steps until the fuel injector return flow is measured at EACH cylinder bank return connection (bank to bank). If the fuel return rates on either head exceed the diagnostic table fuel return rate values, then all eight injectors should be replaced. Record the fuel return rates of the LT and RT head on the attached diagnostic work sheet. This data must be included with the injectors that are requested to be returned to the WPC.
3. Prior to injector removal, be sure to follow the procedures to avoid contamination of injectors.
Important
This condition will not cause an engine misfire. DO NOT apply this bulletin to any diagnostic other than what is identified in the following table. This bulletin only applies to high fuel return rates, not high balance rates. Misfire/high balance rate conditions that are caused by an injector malfunction should be serviced (only replace those that have failed).
- If fuel return flow on either the right or left cylinder bank is above the initial fuel injector bank return flow valve, then replace all eight (8) fuel injectors. Refer to the list of procedures in the next section. This data must be included with the injectors that are requested to be returned to the WPC.
- When installing new fuel injectors, lubricate the inside of the fuel injector sleeve with clean engine oil prior to installing the injector. Do not lubricate the injector or O-ring seal prior to installation.
- Injector sleeves only need to be replaced if there is damage to the tapered sealing surface where it contacts the cylinder head. If an injector sleeve becomes loose or dislodged when replacing the injectors, inspect the cylinder head to sleeve mounting surfaces. If witness marks from a combustion leak or coolant leak are not visible, reseal the sleeve using the procedures for Fuel Injector Nozzle Tube Sleeve Replacement in SI.
Information on Servicing Duramax Diesel Fuel Injectors to Avoid and Remove Contamination
Fuel injectors may become contaminated during engine servicing. Debris between the injector line and the injector line nut may fall into the injector fuel inlet upon removal. Refer to the following SI procedures for the appropriate model year, vehicle, and engine RPO for servicing the fuel injectors and lines.
- Fuel Injection Fuel Rail Assembly Replacement - Bank 1
- Fuel Injection Fuel Rail Assembly Replacement - Bank 2
- Fuel Injector Replacement (Right)
- Fuel Injector Replacement (Left)
Removal of Fuel Injector Lines
1. Before removing the fuel injector line, use regulated compressed air to blow any debris from between the fuel injector line and the fittings (1, 2). Wipe the fittings (1, 2) clean of debris.
2. Spray Super Lube, P/N 12346241 (in Canada, P/N 10953474), or a lithium grease equivalent, between the fuel injector line and fittings (1, 2) to assist in containing any debris during removal.
3. Remove the fuel injector line.
4. Remove the upper valve cover.
5. Remove the lower valve cover.
Notice
After the fuel line is removed and the fuel injector inlet is exposed, DO NOT use compressed air to clean debris. Using compressed air can allow debris to enter the fuel injector inlet and damage the fuel injector.
6. Immediately after removal of the lower valve cover, use a vacuum source to remove any contamination in the fuel injector inlet (1).
Fuel Injector Cleaning and Inspection
Notice
The fuel injector must be cleaned with the proper cleaning equipment. DO NOT use abrasive cleaning methods such as a metallic brush to remove deposits. Cleaning an injector with improper tools may damage the fuel injector.
1. Use a soft bristle non-metallic brush and fuel injector cleaner, P/N 88861802 (in Canada, P/N 88861804), or equivalent, to remove any deposits from the nozzle tip (1) and the copper washer sealing area (2) before reinstallation.
2. Inspect the fuel injector nozzle tip (1) for cracks, dents, or other damage.
3. Inspect the nozzle tip (1) for any signs of discoloration (dark yellow, tan, or blue) due to excessive heat.
Note
For information on injector bore cleaning, refer to Corporate Bulletin Number 05-06-04-067 - Information on New Essential Tool EN-47909 Injector Bore Cleaning Kit for 6.6L Duramax Diesel Engine.
• If any damage is found, replace the fuel injector. Clean the fuel injector bore BEFORE installing the new fuel injector.
4. Clean the fuel injector high-pressure lines by performing the following steps:
5. Inspect the fuel injector high-pressure line for excessive corrosion, scale or rust to the sealing surface as shown.
Notice
Medium size media glass beads have a cleaning and peening action and do not remove metal. They do not have the quick abrasive action of sharp edged media. Glass beads clean rust, scale, and corrosion from metal parts without any damage.
6. Use an Abrasive Blasting Cabinet, P/N 624-AST-SBC1. (to order, call GM Dealer Equipment, or equivalent, with a medium size media glass beads to clean the high pressure lines and fittings.
Important
Black plastic electrical tape or equivalent will protect the fittings outside coating from being removed with the media. This must be done to ALL sixteen high pressure fittings.
7. Install black plastic electrical tape or equivalent on both of the fittings (1) as shown.
8. When using an Abrasive Blasting Cabinet or equivalent, make sure you only clean the inside of the fittings (2) and as much of the fitting threads as possible as shown.
9. Use pipe cleaners (1) to block the ends of the high pressure lines so the abrasive blasting glass beads will not contaminate the inside of the pipes. Before removing the pipe cleaners, clean them by using regulated compressed air to blow any debris and/or media glass beads from the pipe cleaners.
10. There may be some area of the fitting or line that the glass beads did not clean very well. Disregard any surface that did not clean up as long as the area of the fitting is clean at the bite edge or sealing surface. Refer to the above illustration (1). Replace any suspect high pressure line if the glass beads cannot remove corrosion scale or rust from the sealing surfaces and/or pitting or any other damage that is found.
11. After cleaning all of the fuel injector high-pressure line fittings with the glass beads, clean by using compressed air to blow any debris and/or media glass beads from inside and outside of all the fittings and lines. Afterwards, wash thoroughly with All Purpose Parts Cleaner, P/N 88862650 (in Canada, P/N 88901247, Brake Parts Cleaner), or equivalent. Repeat this process until all of the debris and/or media glass beads have been removed from the fittings and lines.
Fuel Injector Installation
Install the fuel injectors and lines using the published service procedures in SI.
Notice
Ensure proper torquing of the fuel injector line fittings (1, 2). An under-torqued fuel injector line will not seal properly and an over-torqued fuel injector line may damage the fuel injector fitting. An improperly sealed or damaged fuel injector line or fuel injector fitting may cause a fuel leak.
Inspection For Fuel Leaks Into the Engine After Fuel Injector Replacement
1. Run the engine at idle for 10 minutes. Inspect for external fuel leaks while the engine is running.
2. Stop the engine and wait 10 minutes, then check the engine oil level. This will be the initial oil level.
3. Run the engine at idle for 5 minutes while commanding the fuel pressure to 160 MPa using a scan tool.
4. Stop the engine and wait 10 minutes, then check the oil level.
• If the engine oil level is more than 4.7 mm (3/16 in) above the initial oil level, refer to Fuel Leak Diagnosis (Inside of Engine), and Fuel in Engine Oil procedures in the Engine Controls and Engine Mechanical sections respectively in SI.
• If the engine oil level is less than 4.7 mm (3/16 in) above the initial oil level, the system is OK.
Fuel Pressure Repair Verification
Important
The diagnostic worksheet, snapshot of the preliminary (actual) fuel rail pressure vs. desired as commanded by the Tech 2(R) to 160 MPa, and a copy of the repair order with technician comments MUST be returned with the removed injectors.
After replacing the injectors, perform the following steps:
1. Connect a scan tool.
2. Prime the fuel system.
3. Start and idle the engine.
4. Command the fuel pressure control to 160 MPa with a scan tool.
• If the fuel pressure is more than 158 MPa, the system is OK.
• If the fuel pressure is less than 158 MPa, refer to System Diagnosis - High Side Pressure in SI.
5. Record all diagnostic data as outlined on a copy of the attached diagnostic worksheet.