5031538 JOHNSON ZINC ASSY, PROTECTION

Illustration 1 g01105705
(1) Primary speed/timing sensor
(2) Secondary speed/timing sensor
(3) Injectors
(4) Fuel pump
(5) 2 Micron secondary fuel filter
(6) Primary fuel filter and water separator
(7) Fuel tank
(8) Fuel pressure regulator
(9) Atmospheric pressure sensor
(10) Engine oil pressure sensor
(11) Engine coolant temperature sensor
(12) Inlet air temperature sensor
(13) Fuel temperature sensor
(14) Engine coolant level sensor
(15) Throttle position sensor
(16) Timing calibration connector
(17) SAE J1939 Data Link
(18) Warning lamp
(19) Diagnostic lamp
(20) Programmable outputs
(21) Electronic Control Module (ECM)
(22) Keyswitch
(23) Battery
(24) Fuel supply railThe electronic unit injector system consists of the following systems: the mechanical system and the electronic system. The mechanical system is made up of the low-pressure fuel supply system and the electronic unit injectors. The electronic system provides complete electronic control of all engine functions. The electronic control system consists of the following three types of components: input, control, and output.There are five major components of the electronic unit injector fuel system:
Electronic unit injectors
Fuel transfer pump
ECM
Sensors
SolenoidsThe electronic unit injectors produce fuel injection pressures up to 207000 kPa (30000 psi). The electronic unit injectors also fire up to 19 times per second at rated speed. The fuel transfer pump supplies the injectors by drawing fuel from the tank and by pressurizing the system between 60 and 125 PSI. The ECM is a powerful computer which controls all major engine functions. Sensors are electronic devices which monitor engine performance parameters. Engine performance parameters measure pressure, temperature, and speed. This information is sent to the ECM via a signal. Solenoids are electronic devices which use electronic currents from the ECM to change engine performance. An example of a solenoid is the injector solenoid.Electronic Controls
The electronic control system provides complete electronic control of all engine functions. The electronic control system consists of the following three types of components: input, control, and output. Sensors monitor engine operating conditions. This information is sent to the ECM. The ECM has three main functions. The ECM provides power for the engine electronics and monitors input signals from the engine sensors. The ECM also acts as a governor to control engine rpm. The ECM stores active faults, logged faults, and logged events. The personality module is the software in the ECM which contains the specific maps that define power, torque, and RPM of the engine. The ECM sends electrical current to the output components to control engine operation. The vehicle harness connects the ECM to the engine control portion of the vehicle harness. The engine control portion includes the following components.
Transmission
Brake
Clutch switches
PTO switch
Data links
Check engine light
Warning light
Engine retarder switch
Speedometer
Tachometer
Cooling fan solenoidThe following list of features are part of the electronic control system:
Cold start strategy
Oil pressure
Coolant temperature warning indicator
Automatic altitude compensation
Variable injection timing
Electronic engine speed governingThese features result in the following items: precise engine speed control, little smoke, faster cold starting, and built-in engine protection.The ECM consists of the following two main components: the ECM and the personality module.The ECM is a computer and the personality module is the software for the computer. The personality module contains the operating maps. The operating maps define the following characteristics of the engine:
Horsepower
Torque curves
Rpm
Other characteristicsThe ECM, the personality module, the sensors, and the unit injectors work together to control the engine. The ECM, the personality module, the sensors, and the unit injectors cannot control the engine alone.The ECM determines a desired rpm that is based on the following criteria:
Throttle signal
Certain diagnostic codes
Vehicle speed signalThe ECM maintains the desired engine rpm by sensing the actual engine rpm. The ECM calculates the fuel amount that needs to be injected to achieve the desired rpm.Fuel Injection Timing and Delivery
The ECM controls the injected fuel amount by varying the signals to the unit injectors. The unit injectors will inject fuel ONLY if the unit injector solenoid is energized. The ECM sends a 105 volt signal to the solenoid for energizing the solenoid. By controlling the timing of the 105 volt signal, the ECM controls injection timing. By controlling the duration of the 105 volt signal, the ECM controls the injected fuel amount.Injection timing is determined by engine rpm, and other engine data. The ECM senses the top center position of cylinder number 1 from the signal that is provided by the engine speed sensor. The ECM decides when the injection should occur relative to the top center position. The ECM provides the signal to the unit injector at the desired time.Unit Injector Mechanism
Illustration 2 g01092960
Typical examples of Electronic Unit Injector fuel systems.
(1) Adjusting nut
(2) Rocker arm assembly
(3) Unit injector
(4) PushrodThe unit injector pressurizes the fuel. The correct amount of fuel is then injected into the cylinder block at precise times. The ECM determines the injection timing and the amount of fuel that is delivered. The unit injector is operated by a camshaft lobe and a rocker arm. The camshaft has three camshaft lobes for each cylinder. Two lobes operate the inlet and exhaust valves, and the other lobe operates the unit injector mechanism. Force is transferred from the unit injector lobe on the camshaft through the lifter to the pushrod (4). The force of the pushrod is transferred through rocker arm assembly (2) and to the top of the unit injector. The adjusting nut (1) allows setting of the unit injector adjustment. Refer to Systems Operation/Testing and Adjusting, "Electronic Unit Injector - Adjust" for the proper setting of the unit injector adjustment.Unit Injector
Illustration 3 g01092963
(1) Solenoid
(2) Tappet
(3) Plunger
(4) Barrel
(5) Nozzle assemblyOperation of the Electronic Unit Injector
The operation of the Electronic Control Unit (EUI) consists of the following four stages: Pre-injection, Injection, End of injection and Fill. Unit injectors use a plunger and barrel to pump high-pressure fuel into the combustion chamber. Components of the injector include the tappet, the plunger, the barrel, and nozzle assembly. Components of the nozzle assembly include the spring, the nozzle check, and a nozzle tip. The cartridge valve is made up of the following components: solenoid, armature, poppet valve, and poppet spring.The injector is mounted in an injector bore in the cylinder head which has an integral fuel supply passage. The injector sleeve separates the injector from the engine