0386056 JOHNSON SAFETY SWITCH ASSY.

Electronic Ignition System (EIS)
The Cat Electronic Ignition System was designed to replace the type of ignition system that has a magneto. The following benefits are the most significant advantages of the electronic ignition system:
Addition of more extensive system diagnostics
Elimination of parts that are prone to mechanical wear
Precise control of ignition timingThe electronic ignition system provides control for the following activities:
Diagnostics of the engine control system
Ignition timing
Protection from detonationIf operating parameters are outside of acceptable limits, the electronic ignition system provides warnings. The system may inhibit the engine operation or may shut down the engine. Also, the system can display some of the operating parameters of the engine.The electronic ignition system includes the following components:
Detonation sensors
EIS control module
Engine speed/timing sensor
Ignition harness
Manifold air pressure sensor
Sensor harnesses
Spark plugs
TransformersControl of the Electronic Ignition System
Illustration 1 g00309805
EIS control module
The EIS control module is a sealed unit with no serviceable parts. Sensors are used to monitor engine operation. Wiring harnesses connect the sensors to the control module. The module uses information from the sensors to determine the ignition timing. The information is also used to provide diagnostics.Note: On newer engines, there is a small door on the front face of the control module. Replace the computer chip inside the control module if updates or special modifications are required.The primary ignition wiring is routed through the engine block. Ignition timing is based on the following variables:
Map of ignition timing that is desired
Engine parametersThe operator can use an electronic service tool to change the following parameters:
Desired timing
Map of speed and timingThe EIS control module has outputs to each ignition transformer. The module also uses sensors and internal circuitry to monitor the system components. If a problem develops in a component or a wiring harness, the control module will sense the problem. The control module will notify the operator by creating a diagnostic code.Ignition Transformers
Each cylinder has an ignition transformer that is located under the valve cover. To initiate combustion in each cylinder, the engine control module sends a pulse to the primary coil of the ignition transformer. The transformer increases the voltage which creates a spark across the spark plug electrode.For the electronic ignition system, the transformers are grounded through the valve cover. Use caution when a valve cover is removed.Always disconnect the ignition harness from the transformer when a valve cover is removed.An ignition harness connects each transformer to the engine control module. The harness is routed inside the engine along the camshaft.Junction Box
Illustration 2 g00787967
(1) Junction box
(2) Emergency stop buttonJunction box (1) contains these components:
Gauges
Meters
Indicators
SwitchesThe junction box also contains the electrical terminal strips that connect the sensors, pickups, and relays to the gauges. In addition, the junction box provides shutoff protection for the engine.Emergency stop button (2) is mounted on the junction box. When this button is pressed, both the fuel and the ignition are shut off.
Do not use this method to stop the engine unless an emergency has occurred. Continuous emergency shutdowns can damage some engine components. These shutdowns will leave unburned fuels in the combustion chambers and in the exhaust system. If an emergency shutdown occurs, purge the system by cranking the engine for 5 to 10 seconds with the ignition shutoff.
The emergency stop button must be reset before the engine will start. Turn the button clockwise. The spring-loaded button will move to the reset position.G3500 Engines use an energize-to-run system. The system can also be configured as an energize-to-shutoff system.
Illustration 3 g00310783
Gas shutoff valve (GSOV)
For an energize-to-run system, the gas shutoff valve (GSOV) must remain energized to supply fuel to the engine.For an energize-to-shutoff system, the GSOV must be energized to shut off the fuel to the engine.The junction box is used to monitor the following parameters:
Engine oil pressure
Engine coolant temperatureIf the engine oil pressure is too low, or if the coolant temperature is too high, a relay will shut off the fuel.Sensors
Sensors provide information to the junction box and the engine control module. The information enables the module to control the engine as efficiently as possible over a wide range of operating conditions. The information is used for monitoring engine operation via gauges and indicators on the junction box and/or the control panel.The sensors also enable the activation of alarms and shutoffs in response to abnormal operation.Air Inlet Temperature
A probe for monitoring the air inlet temperature is located in the air inlet manifold. No adjustment can be made to the temperature range. Excessive inlet air temperature can activate an alarm or a shutdown.Coolant Level
Monitoring of the coolant level is an optional attachment.
Illustration 4 g00851236The coolant level sensor is mounted in the expansion tank. If the coolant level is too low, the sensor can activate an alarm or a shutoff. Coolant must be added to the cooling system to correct the condition.Detonation
Illustration 5 g00455704
Detonation sensor
The detonation sensors monitor