PLATE-CLUTCH 7L7782 - Caterpillar

System Operation Description:When the Engine Control Switch (ECS) is in the AUTO position, and the starting aid switch (SAS) is in the AUTO position, the engine uses an automatic ether system to improve starting in cold temperatures. The system automatically injects ether during the crank cycle. The duration of the ether cycle is based on the engine coolant temperature. The Electronic Control Module (ECM), which controls the ether system, uses the engine coolant temperature sensor to detect engine temperature. The ECM determines if ether should be injected by monitoring actual engine rpm and the engine temperature. The ECM will activate the ether solenoid if the engine coolant temperature is below a set temperature and the engine rpm is below a certain level. The ether will activate for a minimum of 15 seconds at 30 °C (86 °F) up to a maximum of 130 seconds at -50 °C (-58 °F). The automatic ether injection system is disabled whenever engine rpm exceeds 400 rpm or the engine coolant temperature exceeds 30 °C (86 °F).Note: Crank the engine, before you activate the ether injection system in manual mode. Damage to the engine is possible by activating the system when the engine is not turning.The ether injection system can also be operated in manual mode when the SAS is held in the ON position (momentary contact). The ether system is switched into manual mode whenever the starting aid switch is depressed. Manual mode also allows ether to be injected whenever the coolant temperature is less than 30 °C (86 °F) and engine rpm is greater than 50 rpm. Ether is injected in manual mode if the starting aid switch is depressed and the coolant temperature is below the maximum limit. The manual mode will allow ether to be injected for a maximum of 130 seconds when the switch is toggled. The manual ether injection system is disabled whenever engine rpm exceeds 400 rpm or the engine coolant temperature exceeds 30 °C (86 °F).The circuit uses two inputs to the ECM in order to activate the ether system. The two inputs are sinking drivers. The first sinking driver activates the ether start relay. The ether start relay energizes the ether solenoids with 24 3 VDC. In order to prevent damage to the ether solenoids, a second relay is used to keep the solenoids activated by using less voltage. The second sinking driver activates the ether hold relay. The ether hold relay keeps the solenoids energized through the resistor and the diode assembly. The resistor and the diode assembly reduces the voltage to the ether solenoids. The solenoids will be damaged if battery voltage is applied continuously.
Illustration 1 g01023645
Typical circuit with EMCP II
Illustration 2 g01023927
Typical circuit with EMS IITest Step 1. Check for Connector Damage.
Turn the ECS to the OFF/RESET position.
Turn the battery disconnect switch to the OFF position.
Thoroughly inspect the ECM connectors J1/P1 and J2/P2. Inspect all of the other connectors. Refer to the diagnostic functional test Troubleshooting, "Inspecting Electrical Connectors" for details.
Perform a