Programmable Parameters for the Electronic Ignition System
The EIS control module has several parameters that can be programmed for the individual installation. The Caterpillar Electronic Technician (Cat ET) or the Digital Diagnostic Tool (DDT) is necessary for programming the parameters.
For instructions on using Cat ET, refer to the User's Manual that is included with the software.
For instructions on using the DDT, refer to Special Instruction, SEHS9122 that is provided with the tool and refer to Tool Operating Manual, SEHS8806.
The description of the parameter depends on the electronic service tool that is used. The parameters are listed in Table 1. The parameters are described below.
| Programmable Parameters for the Electronic Ignition System | |
| Cat ET Description |
DDT Description |
| "Desired Engine Ignition Timing" | "DES ENG TIMING" |
| "Speed Timing Map" | "SPEED TIMING MAP" |
| "Engine Load Timing Map" | "LOAD TIMING MAP" |
| "Engine Configuration" | "ENGINE TYPE" |
| "Number of Detonation Sensors" | "DET SENSORS" |
| "Engine Compression Ratio" | "COMPRESSION" |
"Desired Engine Ignition Timing" or "DES ENG TIMING"
This parameter determines the desired timing at rated speed. The actual timing may vary due to the timing maps that are programmed, detonation, or operation with propane.
The range for the desired timing is 9.0 to 40.0 degrees BTC.
If the propane input switch is active, the range for the desired timing is 5.0 to 40.0 degrees BTC.
"Speed Timing Map" or "SPEED TIMING MAP"
The selection for this parameter is based on the maximum rated speed of the engine. The map provides ignition timing that is adjusted for the engine speed. The map enhances the engine's performance at different speeds. Table 2 lists the six programmable values and the corresponding engine rpm. The default value is 01.
| Speed Timing Maps | |
| Value | Selection |
| 00 | No map |
| 01 | 1200 rpm |
| 02 | 1100 rpm |
| 03 | 1000 rpm |
| 04 | 1400 rpm |
| 05 | 1500 rpm |
| 06 | 1800 rpm |
The speed timing maps retard the ignition timing by six degrees for a 300 rpm reduction in engine speed. For example, if the number 01 map is selected, the desired timing can be retarded by one degree at 1150 rpm, two degrees at 1100 rpm, etc. The full six degrees of retardation is achieved at 900 rpm.
"Engine Load Timing Map" or "LOAD TIMING MAP"
This parameter has a selection of two maps that are sensitive to the engine load. The parameter can also be disabled. Table 3 lists the three programmable values and the corresponding selection. The default value is 02.
| Load Timing Maps | |
| Value | Selection |
| 00 | No map |
| 01 | "Vacuum Advance Load Sensitive Timing" |
| 02 | "Vacuum Retard Load Sensitive Timing" |
"Vacuum Advance Load Sensitive Timing" - The engine timing is advanced by six degrees when the manifold vacuum reaches an absolute pressure of 50 kPa (7 psi).
"Vacuum Retard Load Sensitive Timing" - The engine timing is retarded by six degrees when the manifold vacuum reaches an absolute pressure of 50 kPa (7 psi).
The timing is retarded back to zero degrees of advance when the manifold vacuum reaches an absolute pressure of 100 kPa (15 psi).
When the manifold vacuum is greater than an absolute pressure of 100 kPa (15 psi), the timing is not changed by either map.
"Engine Configuration" or "ENGINE TYPE"
This parameter is the engine model. The parameter must be programmed for the electronic ignition system to operate properly. The type of engine determines the firing order and the angle of the engine's banks. The type can be programmed 3408 or 3412.
At start-up, the control module verifies that the configuration of the ignition transformers is correct. This confirms correct programming of the type. If this parameter is not programmed correctly, the engine will not start and a diagnostic code will be generated.
"Number of Detonation Sensors" or "DET SENSORS"
This parameter is the number of detonation sensors on the engine. If the value is programmed to zero, the protection from detonation is disabled. If this parameter is not correctly programmed, the engine will not run.
"Engine Compression Ratio" or "COMPRESSION RATIO"
This parameter corresponds to the compression ratio of the engine's pistons.
Other Functions of the Electronic Ignition System
In addition to the programmable parameters, the EIS control module is used for the following functions:
- Monitoring the components and the operation of the electronic ignition system
- Timing calibration