PUMP GP-PISTON 6E0838 - Caterpillar

System Operation
This engine was designed for electronic control. The injection pump, the fuel lines and the nozzles that are used in mechanical engines have been replaced with an electronic unit injector in each cylinder. A solenoid on each injector controls the amount of fuel that is delivered by the injector. The Electronic Control Module (ECM) sends a signal to each injector solenoid in order to provide complete control over the operation of the fuel injection system.Electronic Controls
The electronic system consists of the following components: the ECM, the electronic unit injectors (EUI), the wiring harnesses, the switches and the sensors. The ECM is the computer. The personality module is the software for the computer. The personality module contains the operating mapsthat define the following characteristics of the engine:
Horsepower
Torque curvesThe ECM determines the timing and the amount of fuel that is delivered to the cylinders. These decisions are based on the actual conditions and/or on the desired conditions at any given time.The ECM compares the desired engine speed to the actual engine speed. The actual engine speed is determined through the engine speed/timing sensor. The desired engine speed is determined through the following items:
Throttle signal
Other input signals from sensors
Certain diagnostic codesIf the desired engine speed is greater than the actual engine speed, the ECM injects more fuel in order to increase the actual engine speed.Fuel Injection
The ECM controls the amount of fuel that is injected by varying the signals to the injector solenoids. The injectors will pump fuel only if the injector solenoid is energized. The ECM sends a 105 volt signal to the injector solenoid. By controlling the timing and the duration of the high voltage signal, the ECM can control injection timing and the ECM can control the amount of fuel that is injected.The ECM limits engine power during "Cold Mode" operation and the ECM modifies injection timing during "Cold Mode" operation. "Cold Mode" operation provides the following benefits:
Increased cold weather starting capability
Reduced warm-up time
Reduced white smoke"Cold Mode" is activated whenever the engine's coolant temperature falls below a predetermined value. "Cold Mode" remains active until the engine's coolant temperature rises above a predetermined value.The personality module inside the ECM sets certain limits on the amount of fuel that can be injected. The Fuel Ratio Control (FRC) is used to control the air/fuel ratio for control of emissions. The FRC is a limit that is based on the turbocharger outlet pressure. A higher turbocharger outlet pressure indicates that there is more air in the cylinder. When the ECM senses a higher turbocharger outlet pressure, the ECM increases the FRC. When the ECM increases the FRC, the ECM allows more fuel into the cylinder. The FRC is programmed into the personality module at the factory. The FRC cannot be changed.The rated fuel position is a limit that is based on the power rating of the engine. The rated fuel position is similar to the rack stops and to the torque spring on a mechanically governed engine. The rated fuel position