0328751 JOHNSON CUP,Impeller housing

Electronic Controls
The electronic control system consists of the ECM and the personality module. The ECM is the hardware which controls the engine. The personality module is the software that controls the ECM.Rack Controls
The ECM adjusts the voltage to the rack solenoid in order to increase the rack position. The ECM also adjusts the voltage in order to decrease the rack position. An increase in voltage to the rack solenoid will increase the fuel rate. The rack solenoid moves a spool valve to control oil pressure to a servo that controls the rack position.
Illustration 1 g01621681The throttle inputs allow the ECM to determine the desired engine speed. Also, the customer specified parameters will determine the speed. The ECM maintains the desired engine speed by sensing the actual engine speed with the engine speed sensor. The ECM controls the rack solenoid in order to achieve the desired speed.The ECM sets limits on the amount of fuel that can be injected. The rack of the fuel ratio control operates in the same manner as the fuel and air control on a mechanically governed engine. When the ECM senses a higher inlet manifold pressure, the limit of the rack for the fuel ratio control is increased in order to allow more fuel. The rated rack is a limit which is based on the power rating of the engine. The rated rack determines maximum power values and torque values of a specific engine family and rating. The rack of the fuel ratio control and the rated rack are programmed by the factory into the personality module.Programmable Parameters
Programmable parameters will affect engine operation. These parameters may be changed with an electronic service tool. The parameters are stored in the ECM. These parameters are system configuration parameters or customer parameters. System configuration parameters are parameters that affect the power rating or the emissions. Customer parameters affect settings such as low idle and high idle.Passwords
System configuration parameters are protected from unauthorized changes by factory passwords. Customer parameters are protected by customer passwords that are programmed by the customer.Self-Diagnostics
The ECM has a limited ability to make a self-diagnosis. A diagnostic code is generated when the ECM detects a problem. The diagnostic code is indicated on the diagnostic lamp as a series of flashes. In most cases, the code is stored in the permanent memory of the ECM. Active codes represent a current problem. Service an active code first.Diagnostic codes that are stored in memory are called logged codes. Logged diagnostic codes do not always require repair. The problem could have been temporary. Logged diagnostic codes may be an indicator of intermittent problems. Some logged diagnostic codes record events rather than failures. Diagnostic codes will automatically reset after 100 hours if the code does not require a factory password to clear the code. Engine Speed Switch
The engine speed switch is designed to monitor several functions at the same time. Primary functions of the engine speed switch are engine overspeed and crank termination.Engine Overspeed
This is an adjustable engine speed setting that prevents the engine from running at a speed that could cause damage. An overspeed condition causes a relay to open and the relay will de-energize the shutoff solenoid. This will stop the fuel flow to the engine. Also, this will shut down the engine. The engine speed switch may activate the emergency air shutoff system by de-energizing the air shutoff solenoid.
Illustration 2 g01621694Note: If the overspeed switch is faulty, a jumper can be used to bypass relay "SR1" to allow the engine to operate normally.Crank Termination
The programmable crank termination speed is the engine rpm that is achieved prior to disengagement of the starting motor. The engine hour meter activates after the engine speed of the crank termination is reached and a set of contacts opens. Load Share Module
The load share module allows the connection of one generator set in parallel with another generator set. The load share module senses the power output of the generator set engine. The load share module provides a pulse width modulated signal. The signal is used to adjust the power output of the other generator set.Warning Lamps
The ECM provides outputs in order to drive six different warning lamps. The warning lamps alert the operator of certain operating conditions.The following output lamps are used.
Low oil pressure
High coolant temperature
Low coolant level
Low boost pressure
Derate from atmospheric pressure
DiagnosticThe diagnostic lamp displays diagnostic conditions. The conditions are detected by the ECM. Flash codes are used to detect these conditions.