98 ENGINE COMPONENT AND LOCATION Unit Injectors W2033328 1. Injector Yoke 8. Solenoid Coil 2. Copper Sleeve 9. Solenoid Coil 3. O-Ring 10. Injector Valve 4. Fuel Gallery 11. Injector Piston 5. O-Ring 12. Injector Nozzle 6. O-Ring 13. Washer 7. Pressure Relief Valve This engine uses double solenoid unit injectors. Unlike systems that require separate components for delivering, pressurizing and injecting, this unit injector combines these functions. These injectors precisely control the fuel delivery because of the two solenoids. The solenoids, pump and nozzle are in a single body in close proximity to each other.
The injector is set in a pressurized fuel gallery where the fuel temperature is constant. Uniform fuel temperature means uniform quantity in each injection which means uniform power output from each cylinder. The fuel pump pressurizes the gallery so that fuel rushes into each injector when it opens. Gallery pressure is regulated by a valve that delivers excess fuel back to the tank. Copper sleeves, acting as coolant jackets, line the bottoms of the injector bores. Engine coolant circulates around these sleeves aiding the process of controlling injection temperature.