GEAR (17 and 21 teeth) 5A5740 - Caterpillar

EngineC13 (S/N: LEE1-UP)C15 (S/N: SDP1-UP)Introduction
Do not perform any procedure in this Special Instruction until you have read the information and you understand the information.MEUI-C fuel injectors installed in certain C13 and C15 truck engines have failed due to issues not related to materials or workmanship of the injector. Injector solenoid failures have occurred due to fuel system restrictions and connector pin arcing. Other injector failures have been related to incorrect injector rocker preload. To prevent more failures, further troubleshooting and inspection of the fuel system and electrical connectors is necessary to determine the root cause of the solenoid failure. Likewise, if injector tappet or injector rocker failures are observed, investigations should review that correct injector preload procedures were followed.Note: Failures of injectors that are not due to defects in manufacturing or materials may not be warrantable failures.
Illustration 1 g06304350
Illustration 2 g06196094
(1) Normal Solenoid
(2) Overheated SolenoidFuel System Restrictions
Adequate fuel flow rate through the engine is required to cool fuel injectors and injector solenoids. Contaminated fuel combined with inadequate maintenance of the secondary fuel filter can reduce fuel flow rate. Fuel filter restrictions can cause fuel to bypass internally within the secondary filter base. This bypass will allow fuel flow to return to tank without cooling the fuel injectors.Troubleshooting of injector failures should include investigation of secondary filter internal bypass. Internal bypass can be indicated by measuring fuel pressure at the sample port that is on the secondary filter base. Fuel bypass will occur as pressure approaches 655 kPa (95 psi) at the sample port. High-pressure measurements with the engine operating at low idle are especially concerning.Pressure measurement at the sample port differs from the measurement of pressure near the engine cylinder head. Pressure measured at the sample port is immediately upstream of the fuel filter element and the 689 kPa (100 psi) pressure regulator.Refer to the following publications for more details and specifications:
Refer to Systems Operation, RENR9808, "Fuel System".
Refer to Troubleshooting, RENR9343, "Fuel System Pressure - Test".
Refer to Troubleshooting, RENR9343, "Injector Solenoid - Test".
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(3) Fuel pressure sampling portConnector Pin Arcing
Injector solenoid diagnostic codes can be a result of poor electrical connections between the injector and injector harness. When troubleshooting a suspected injector failure, carefully inspect injector connector pins for signs of arcing. If arcing is observed, both injector and harness must be replaced to prevent additional injector failures. Pin arcing will degrade the corresponding socket and result in poor electrical conductivity.
Illustration 4 g06300012Refer to the following publications for more details and specifications:
Refer to Troubleshooting, RENR9343, "Injector Solenoid - Test".
Refer to Service Magazine, SEPD1840, "A New Improved Removal and Installation of the Injector Harness Procedure is Now Used on Certain C13, C15, and C18 Engines".
Refer to Engine News, SEBD9957, "A New Improved Removal and Installation of the Injector Harness Procedure is Now Used on Certain C13, C15, and C18 Engines".Improper Injector Rocker Preload
Injector failures can result from improper preload of the injector rocker. Typical failure modes may include separation of tappet from injector or injector seizure as the result of injector rocker