CAMSHAFT 8N3981 - Caterpillar

The Electronic Control Module (ECM) contains the logic and the outputs for control of starting and of shutdown. The ECM responds to signals from the following components: engine control, emergency stop switch, remote start, data link, and driven equipment.The following Steps describe the electronic control system start/stop sequencing:
The ECM receives one of the following signals for start-up:
The engine control is set to the "START" mode.
The engine control is in the "AUTO" mode and the remote start/stop initiate contact closes.
Once the start signal is received, the ECM supplies +Battery voltage to the solenoid for the starting motor. If the engine was not successfully purged during the previous engine shutdown, the engine purge cycle is enabled, and the starting motor cranks the engine without fuel and without ignition until the "Engine Purge Cycle Time" has elapsed.The "Engine Purge Cycle Time" allows any unburned fuel to exit through the exhaust system prior to ignition. The cycle helps prevent combustion in the exhaust system.If the engine was successfully purged during the previous engine shutdown, the engine purge cycle will be disabled during the first start-up attempt to minimize start time.For further details refer to the "Generator Set Fast Start Setup" section in the Special Instructions document.
The engine has an energize-to-run type of GSOV. This statement means that the GSOV must be energized to open. When the GSOV is open, fuel is allowed to flow to the engine.Once the ECM energizes the GSOV, the ECM will energize the auxiliary fuel GSOV and send fuel commands to both the main fuel metering valve and the auxiliary fuel metering valve to supply sufficient fuel for a combustible air/fuel mixture. The ECM also sends a throttle command to the throttle actuator. Once the engine has achieved pattern lock, the ECM will energize the ignition transformers.Engine diagnostics are in place to protect the engine during starting, so the engine may shutdown if any of the following events occur:
- Engine ECM does not receive engine speed signal within a certain amount of time as specified in the engine software
- Engine ECM does not receive pattern lock within a certain amount of time as specified in the engine software
After the engine starts and the programmable crank terminate speed is achieved, the ECM removes the voltage from the starting motor solenoid. The pinion of the starting motor disengages from the flywheel ring gear. The ECM also deactivates the auxiliary fuel GSOV and auxiliary fuel metering valve.
The engine runs until the ECM receives a shutdown signal.The following conditions cause a shutdown signal:
The remote start/stop initiate contact opens when the engine control switch is in the "AUTO" position.
The engine control is in the "COOLDOWN /STOP" mode.
The "EMERGENCY STOP" button is pressed.
The ECM senses an undesirable operating condition and an engine shutdown is initiated.The engine control "OFF/RESET" is not recommended for normal shutdown. The "EMERGENCY STOP" is not recommended for normal shutdown. Only the "EMERGENCY STOP" and an overspeed condition will cause both the fuel and the ignition to be stopped immediately. The