STRAINER AS 3G7250 - Caterpillar

The engine is designed for electronic control of most engine operating functions. The electronic system consists of an Electronic Control Module (ECM), the wiring harness, switches, sensors, and fuel injectors. The engine ECM receives information from the sensors and the switches on the engine. The engine ECM processes the information that is collected in order to control the engine. By altering the fuel delivery with the fuel injectors, the engine ECM controls the speed and the power that is produced by the engine.Electronic Controls
Electronic Control Module
The ECM consists of two main components, the control computer (hardware) and the flash file (software). The control computer consists of a microprocessor and electronic circuitry. The flash file contains the engine operational characteristics. The operating maps influence the engine performance.Engine Governor
The engine ECM governs engine speed. The engine ECM and the flash file work together by controlling the amount of fuel that is delivered by the injectors. Desired engine rpm is determined by the throttle position sensor signal and certain sensor readings. Diagnostic codes may derate the engine. Actual engine rpm is measured by the engine speed/timing signal.Fuel Injection
The engine ECM controls the timing and the duration of the fuel that is injected. The engine ECM varies the signals to the fuel injectors. Fuel is injected only while an injector solenoid is energized by a 105 V signal from the engine ECM. The timing of the injection signal determines the engine timing. The length of the injection signal determines engine speed. By controlling the timing and duration of the 105 V signal, the ECM controls the engine speed.Injection timing depends on the following conditions: desired engine rpm and load. The ECM detects the top center of each cylinder. The ECM sends an injection signal at the desired time.Cold Mode Operation
The engine ECM uses cold mode operation in order to reduce white smoke during engine warm-up. The engine ECM cuts out the injectors one at a time in order to determine if the cylinder is firing. If the cylinder is firing correctly, the engine ECM leaves the injector on. If the cylinder is not firing, the engine ECM will leave the injector turned off. This action will increase startability and this action will reduce warm-up time.Cold mode is activated whenever the engine coolant temperature falls below a predetermined value. Cold mode remains active until the engine has warmed or a time limit is exceeded.FRC Limit
The flash file inside the engine ECM sets certain limits on the amount of fuel that can be injected. The FRC limit is a limit that is based on the boost pressure. The boost pressure is calculated as the difference in pressure between atmospheric pressure and turbocharger outlet pressure. The FRC limit is used to control the air/fuel ratio for control of emissions. When the engine ECM senses a higher boost pressure, the engine ECM increases the FRC limit. A higher boost pressure indicates that there is more air in the cylinder. When the engine ECM increases the FRC