SPACER 4Y0771 - Caterpillar

The electronic ignition system includes these components: EIS control module, engine speed/timing sensor, manifold air pressure sensor, detonation sensors, ignition transformers, spark plugs and wiring harnesses. The EIS control module is wired to an engine mounted junction box. The junction box provides an interface for communication between the operator and the EIS control module via a Digital Diagnostic Tool (DDT).Illustration 1 demonstrates the relationship between the parts of the system.
Illustration 1 g00818126
Schematic of the electronic ignition system and related components (1) Remote control panel (status) (2) Engine mounted junction box (3) Engine speed/timing sensor (4) Manifold air pressure sensor (5) Detonation sensor (6) EIS control module (7) DDT (8) Ignition transformer (9) Spark plugEIS control module (6) is mounted on the engine. The EIS control module must be programmed for the installation in order to properly control the ignition. DDT (7) is used to program the EIS control module. The DDT can be connected to remote control panel (1) or junction box (2) .Note: For information on the programmable parameters, refer to Systems Operation, "Electronic Control System Parameters". For information on the monitoring system, refer to Systems Operation, "Engine Monitoring System".Two switches have an effect on the ignition system: the engine control switch and the switch for fuel selection.When the engine control switch on remote control panel (1) is switched to the manual start position, the EIS control module begins operating the ignition system.If the switch for fuel selection is in the natural gas position, the EIS control module will use the desired timing that is programmed. If the switch for fuel selection is in the propane position, the EIS control module retards the timing by ten degrees.The EIS control module uses engine speed/timing sensor (3), manifold air pressure sensor (4), and detonation sensors (5) to monitor engine operation. The EIS control module determines the optimum ignition timing for the engine operation and the module initiates the timed ignition via ignition transformers (8) and spark plug (9) .Information from the EIS control module is sent to engine mounted junction box (2) and the remote control panel. If a problem with the electronic system is detected, a diagnostic code is generated. The diagnostic code can be monitored with the remote control panel or with the DDT.The EIS control module has several internal components that perform different functions. The components and the functions are listed in Table 1.
Table 1
Internal Components and Functions of the EIS Control Module    
Component     Function    
Ignition control     Receive input from the engine control switch, the switch for fuel selection, and the DDT.    
Provide information on engine status and diagnostics to electronic service tools.
Provide desired timing and voltage to the ignition transformers' control.
Receive input from the interpreters and the filter.
Ignition transformers' control     Receive input from the ignition control.    
Provide voltage to the transformers.
Provide input to the interpreter of diagnostics for the transformers.
Interpreter of diagnostics for the transformers     Receive input from the ignition transformers' control.    
Provide input to the