Usage:
3176 (7LG7500-Up) Truck Engines
Reference: This issue of Service Magazine, "New 9U6143 Power Supply Adapter Allows New Unit Injectors To Be Tested On 1U6661 Or 6V4022 Pop Testers"
Reference: This issue of Service Magazine, "Application Changes For Electronic Unit Injector (EUI) Part Numbers".
Description of Change: A new EUI with a new style solenoid is used. The new style solenoid can be identified by the ivory colored, non-metallic case. Formerly, the solenoids had a full metallic case. The new EUI is used with a new unit injector wiring group. The new group includes a new wiring harness and cap assembly. The new wiring harness includes a new connector that connects both EUI terminals at once. The new cap assembly captures the two electrical terminal nuts and reduces the chance of dropping the small nuts into the engine.
The new EUI is installed in the cylinder head in the same manner as the former design. When installing the new wiring harness, the EUI connector can be flipped over to align the terminal posts with the kidney shaped slots in the connector. It does not matter which EUI terminal post the wires are connected to, as long as each connector is on the correct cylinder. The correct cylinder is marked on each connector on the black web between the wires. See Illustration 1. After the connector is in installed, put the new 7E6508 Cap Assembly in position and tighten the terminal nuts to a torque of 1.7 N·m (15 lb in).
Illustration 1. Top view of cylinder head with new EUI's and new unit injector wiring group. The arrows point at the locations where the electrical connectors are marked with the cylinder number.
Illustration 2. View A-A rotated 90° counterclockwise. Location of new electrical connector (1), 7E6508 Cap Assembly (2), and 6I2870 EUI (3).
Adaptable To: The new 6I2870 EUI and 6I2866 Unit Injector Wiring Group are in effect with 275 and 300 hp 3176 Truck Engine 7LG7500. The new style components are not interchangeable with the former components.
Pop testing the EUI with the new style solenoid requires the addition of the 9U6143 Power Supply Adapter to the 1U6661 or 6V4022 Pop Testers. See the article "New 9U6143 Power Supply Adapter Allows New Unit Injectors To Be Tested On 1U6661 Or 6V4022 Pop Tester" in this issue. Pop testing the new EUI without the power supply adapter installed on the pop tester will result in damage to the EUI solenoid.