101492-0421 ZEXEL INJECTION-PUMP ASSEMBLY Cross 1014920421 8943296901

3176 Electronic Governor Fuel Injection
The ECM controls the amount of fuel injected, by varying signals to the injectors. The injectors will inject fuel ONLY if the injector solenoid is energized. The ECM sends a 100 volt signal to the solenoid to energize it. By controlling the timing and duration of the 100 volt signal, the ECM can control injection timing and the amount of fuel injected.The ECM sets certain limits on the amount of fuel that can be injected. "FRC Fuel Pos" is a limit based on boost pressure to control the fuel-air ratio, for emissions control purposes. When the ECM senses a higher boost pressure (more air into cylinder), it increases the "FRC Fuel Pos" limit (allows more fuel into cylinder). "Rated Fuel Pos" is a limit based on the horsepower rating of the engine. It is similar to the rack stops and torque spring on a mechanically-governed engine. It provides horsepower and torque curves for a specific engine family and rating. All of these limits are programmed by the factory into the Personality Module and are not programmable in the field.Injection timing depends on engine rpm, load and other operation factors. The ECM knows where top-dead-center of cylinder number one is from the signal provided by the engine Speed/Timing Sensor. It decides when injection should occur relative to top-dead-center and provides the signal to the injector at the desired time.Under certain conditions, the 3176 Engine may intentionally operate on just three cylinders. This feature is called "Three Cylinder Cutout" and occurs when the engine is operated under no load, at high rpm (when signals to the injectors are of very short duration). Under these conditions, the ECM does not inject fuel into cylinders 4, 5 and 6. This allows for more precise fuel metering to cylinders 1, 2 and 3. The accompanying change in feel and sound of the engine should not be misdiagnosed as an engine problem. When more power is needed, all six cylinders will be fueled and full power delivered.Programmable Parameters
Certain parameters that affect 3176 Vehicular Diesel Engine operation may be changed through electronic service tools (either the ECAP or DDT). The parameters are stored in the ECM and passwords are used to prevent unauthorized changes.Password protected parameters are either "System Configuration Parameters" or "Customer Specified Parameters". System Configuration Parameters are set at the factory and affect emissions or horsepower ratings within a family of engines. Factory passwords must be obtained and used to change System Configuration Parameters. Customer Specified Parameters are variable and can be used to affect such things as the rpm/horsepower ratings within the limits set by the factory. Customer Passwords must be used to change Customer Specified Parameters.If the operator has not had adequate training, some parameters may affect engine operation in ways that are not expected. This may lead to power or performance complaints, even though the engine is operating correctly.Passwords
"System Configuration Parameters" are protected by factory passwords. System Configuration Parameters are those that affect horsepower family or