Installation and Initial Start-Up Procedure for G3500C and G3500E Generator Set Engines {1000, 1000, 1264, 1408} Caterpillar

Engine

G3512E (S/N: SSR1-UP; NGS1-UP)

G3520C (S/N: GZJ600-UP)

G3520E (S/N: GZE1-UP)

Introduction

Do not perform any procedure in this Special Instruction until you read this information and you understand this information.

This Special Instruction provides the following information for G3500C and G3500E Engines:

• Requirements for the electrical system

• Proper grounding practices

• Proper welding practices

• Required service tools

• Electrical components and electronic components

• Wiring connections and the corresponding functions that are available to the customer

• Initial start-up procedure

• Governor adjustment procedures

Reference: Information from the following sources will be needed for this Special Instruction:

• Data from a complete fuel analysis using Gas Rating Pro (GERP).

• The engine performance Data Sheet from the engine Technical Marketing Information (TMI)

• Operation and Maintenance Manual, SEBU7681

• Systems Operation/Testing and Adjusting, RENR5978, "G3520C and G3520E Generator Set Engines"

• Systems Operation/Testing and Adjusting, KENR9737, "G3512E and G3520E Generator Set Engines"

• Systems Operation/Testing and Adjusting, SENR5832, "Electronic Modular Control Panel II+ (EMCPII+)"

• Troubleshooting, RENR5944, "G3520E Generator Set Engines"

• Troubleshooting, RENR5979, "G3520C and G3520E Engines"

• Troubleshooting, KENR9738, "G3512E Generator Set Engines"

Requirements for the Electrical System

All of the wiring must conform to all of the codes that are applicable to the site. When you route the wiring, avoid acute bends and sharp edges. To protect the wiring harnesses, route the harnesses through metal conduit. A liquid tight conduit is recommended. Use proper support and alignment to avoid strain on the conduit.

Electrical power must be supplied to the junction box that serves as the main distribution panel for the engine control system. The engine control system requires a clean 24 VDC power supply capable of supplying 30 A of continuous power.

The maximum allowable ripple voltage is 150 mV AC peak to peak. For the wiring, the maximum allowable voltage drop is 1 VDC from the power supply to an Electronic Control Module (ECM) or to an actuator.

The power supply for the engine control system must be separate from the power supply for the starting motor.

Grounding Practices

Proper grounding is necessary for optimum engine performance and for reliability. Improper grounding will result in electrical current paths that are uncontrolled and unreliable.

Uncontrolled electrical circuit paths can result in damage to main bearings, to crankshaft bearing journal surfaces, and to aluminum components. Uncontrolled electrical circuit paths can also cause electrical activity that may degrade the engine electronics and communications.

• For the starting motor, do not attach the battery negative terminal to the cylinder block.

• Use an electrical ground strap to connect all metal cases that contain electrical components or electronic components to the cylinder block.

• Do not connect the negative terminal from the electrical power supply directly to the cylinder block. Connect the negative terminal from the electrical power supply to the negative terminal "−" on the engine mounted junction box.

• Ground the cylinder block with a ground strap that is furnished by the customer. Connect this ground strap to the ground plane.

• Use a separate ground strap to ground the battery negative terminal for the control system to the ground plane.

• Rubber couplings may connect the steel piping of the cooling system and the radiator. The rubber isolates the piping and the radiator. Ensure that the piping and the radiator are continuously grounded to the cylinder block. Use ground straps that bypass the rubber couplings.

• Ensure that all grounds are secure and free of corrosion.

Welding on Electronically Controlled Engines

Proper welding procedures are necessary to avoid damage to electronic controls. Perform welding on the engine according to the following procedure.

1. Set the engine control to the "STOP" mode.

2. Turn OFF the fuel supply to the engine.

3. Disconnect the negative terminal from the battery.

4. Disconnect the engine electronic components from the wiring harnesses: ECM, throttle actuator, actuator for the turbocharger compressor bypass, fuel metering valve and sensors.

5. Protect the wiring harnesses from welding debris and/or from welding spatter.
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   NOTICE
   Do NOT use electrical components (ECM or sensors) or electronic component grounding points for grounding the welder.

6. Connect the welder ground cable directly to the engine component that will be welded. Place the clamp as close as possible to the weld to reduce the possibility of welding current damage to the engine bearings, to the electrical components and to other engine components.

7. Use standard welding procedures to weld the materials together.

Service Tools

The tools listed in Table 1 are required to enable a service technician to perform the electrical installation procedures and the initial start-up.

The Caterpillar Electronic Technician (ET) is designed to run on a personal computer.

Cat ET can display the following information:

• Parameters

• Diagnostic codes

• Event codes

• Engine configuration

• Status of the monitoring system

Cat ET can perform the following functions:

• Perform diagnostic tests.

• Calibrate sensors.

• Download flash files.

• Set parameters.

Table 1 is a list of required service tools.

Note: For additional operational information about Cat ET and PC requirements for Cat ET, refer to the documentation that accompanies your Cat ET software.

Connecting Cat ET with the Communication Adapter Assembly

Illustration 1	g03779523
Connecting Cat ET to the service tool connector (1) Service tool connector

Refer to Illustration 1. The location of the service tool connector depends on the configuration of the control system.

The engine power supply supplies the communication adapter with 24 VDC. Use the following procedure to connect Cat ET and the communication adapter to the engine.

1. Set the engine control to the OFF/RESET mode.

2. Connect communications adapter to a communications port on the PC.

3. Connect communications adapter to the service tool connector.

4. Verify that the "POWER" indicator on the communication adapter is illuminated.

5. Set the engine control to the STOP mode. Establish communication between Cat ET and an ECM. If Cat ET and the communication adapter do not communicate with the ECM, refer to Troubleshooting, "Electronic Service Tool Does Not Communicate With ECM".

Terminal Box

Note: The terminal box is designed to remain mounted on the engine. The mounting hardware includes isolators. Do not move the terminal box to a remote location. Moving the terminal box could result in wiring problems and in reduction of the service life of the components inside the terminal box.

Illustration 2	g01298930
Typical terminal box

The terminal box contains the electronic control modules. Connectors on the terminal box connect the engine wiring harnesses to components inside the terminal box. The ignition harnesses are routed directly from each ECM to the ignition transformers.

There are four configurations for the terminal box. Refer to the following Illustrations: 3 and 4.

Illustration 3	g03779536
The configuration for a 12 cylinder engine is shown. (1) Terminal box (2) Master ECM (3) P2 connector (4) P1 connector (8) Integrated Temperature Sensing Module (ITSM) (9) Emergency stop button (10) Service tool connector (11) P6 customer connector (12) P7 connector (13) P8 connector (14) P9 connector (16) Panel light switch

Illustration 4	g03779560
The configuration for a 20 cylinder engine is shown. (1) Terminal box (2) Master ECM (3) P2 connector (4) P1 connector (5) Slave ECM (6) P3 connector (7) P4 connector (8) Integrated Temperature Sensing Module (ITSM) (9) Emergency stop button (10) Service tool connector (11) P6 customer connector (12) P7 connector (13) P8 connector (14) P9 connector (16) Panel light switch

Junction Box

The junction box is the main distribution panel for the engine electrical power. The junction box contains all the circuit breakers for the engine. The junction box also contains the magnetic switches for the electric starting motors.

Illustration 5 shows the junction box.

Illustration 5	g01299586
The junction box is on left side of the engine. (1) Junction box (2) 2.5 amp circuit breaker for the engine control (3) 10 amp circuit breaker for the customer (4) 35 amp circuit breaker for the engine control main power supply (5) 2.5 amp circuit breaker for the start command from the ECM (6) Positive terminal for the connection of the engine power supply (7) Negative terminal for the connection of the engine power supply

Customer Wiring

To wire the engine for the application, the customer must be aware of several inputs and outputs associated to the engine control system. The following list provides some examples of the inputs and outputs:

• Emergency stop

• Electrical power supply for the control system

• Start-up and shutdown

• Engine speed and governing

• Status of engine operation

There are two possible locations for the customer connections.

• P6 customer connector on the terminal box

• Terminal strip inside the generator housing

P6 Customer Connector On The Terminal Box - The location of the customer connector depends on the engine configuration. Refer to Illustration 6. The 9X-7147 Connector Plug is available for the customer to connect a wiring harness to the P6 customer connector. The 9X-7147 Connector Plug accepts 16 or 18 AWG size of wire.

Illustration 6	g01299684
P6 customer connector on the left side of the terminal box

Terminal Strip (1) Inside the Generator Housing - Refer to Illustration 7. This terminal strip is connected to the P6 customer connector via a wiring harness. The Electronic Modular Control Panel (EMCP II+) (if equipped) is also connected to this terminal strip.

Illustration 7	g01299896
Left side of the generator housing (1) Terminal strip

EMCP II+ - There are two possible configurations for the EMCP II+. EMCP II+ (2) is mounted to the top of the generator. The connections to this panel are made at the factory. EMCP II+ (3) is wall mounted. Terminal strip (4) is used to make the connections between the EMCP II+ and the terminal strip inside the generator housing.

Illustration 8	g01300125
EMCP II+ (2) Mounted on top of the generator (3) Wall mounted (4) Terminal strip

Some of the connections are required. Some of the connections are optional. The connections that are required are identified in Table 2. The connections that are optional are identified in Table 3.

Required Connections

Connections

Wiring for the Emergency Stop Circuit

The emergency stop circuit must be wired properly to stop the engine in case of an emergency situation. An emergency stop button is provided on the engine. An emergency stop button is also provided on the control panel for the EMCP II+. Additional emergency stop buttons may be installed at the site.

The circuit for the emergency stop is normally closed. If an emergency stop button is pressed, the circuit is opened. Electrical power to the ignition system is immediately removed by the engine control system. If the engine control system is controlling the GSOV, the ECM immediately removes the voltage from the GSOV. The flow of fuel is stopped.

In addition to the normally closed electrical circuit for emergency stopping, the emergency stop button is mechanically connected to another circuit that is normally open. When the emergency stop button is pressed, this other circuit is closed. This other circuit does not affect engine operation. This other circuit is available to the customer via terminals J6-2 and J6-12. These terminals are provided for the customer to use as an indicator of an emergency stop.

Illustrations 9 and 10 are schematic diagrams for the emergency stop circuit.

Illustration 9	g03779584
Schematic diagram for the emergency stop circuit The EMCP II+ is mounted on top of the generator.

Illustration 10	g03779587
Schematic diagram for the emergency stop circuit The EMCP II+ is wall mounted.

Wiring for the Gas Shutoff Valve (GSOV)

The GSOV must be energize-to-run. The GSOV may be supplied by the customer or by Caterpillar. Usually, the GSOV is installed when the piping for the fuel is installed at the site. The GSOV may be controlled by the engine control system or by the customer equipment. The GSOV is also called the fuel control relay.

The ECM can supply a maximum continuous current of 1.5 A to the GSOV. A relay must be installed if the GSOV requires a continuous current that is greater than 1.5 A.

When the engine control system controls the GSOV, the ECM supplies voltage to the GSOV. The valve opens to allow fuel to flow to the engine. When voltage is removed from the GSOV, the valve closes and the fuel flow stops.

When the customer equipment controls the GSOV, the necessary logic must be used to ensure that the GSOV opens and closes at the appropriate times.

There are several options for wiring the GSOV. Consider the following information:

• The circuit for the GSOV must be complete in order for the engine to crank.

• The circuit for the GSOV must remain complete in order for the engine to run.

• The GSOV can be connected anywhere in the circuit.

Some possible configurations are discussed in the following paragraphs.

The GSOV is controlled by the customer equipment. In this case, the circuit for the engine control system must be a complete path. The circuit must include a resistor. Otherwise, a diagnostic code will be activated and the engine will not start. Illustration 11 is an example of this type of installation.

Illustration 11	g03779595
The GSOV is controlled by the customer equipment.

The GSOV is controlled by the engine control system. The engine harness is used for the connection. The customer may supply an additional switch in the electrical circuit for the GSOV. If the customer does not provide an optional switch, the circuit must be closed. Refer to Illustration 12 for an example of this type of installation.

Illustration 12	g03779612
The GSOV is controlled by the engine control system.

The GSOV is controlled by the engine control system. The GSOV is connected to a harness that is provided by the customer. The customer may supply an additional switch in the electrical circuit for the GSOV. Refer to Illustration 13 for an example of this type of installation.

Illustration 13	g03779615
The GSOV is controlled by the engine control system. The GSOV is connected via wiring that is provided by the customer.

Note: Most GSOV's will require a contractor or relay be used between the engine circuit and the GSOV.

Wiring for Monitoring the Generator Output Power

The ECM monitors the generator output power to control the air/fuel ratio. The ECM uses an output from one of the following sources to monitor the generator output power:

• EMCP II+

• Programmable Logic Controller (PLC)

• Wattmeter

The PLC and the wattmeter are also called power sensors.

If the generator is equipped with the EMCP II+, information on the engine load is provided via the Cat data link. The wiring is installed at the factory. No additional connections are needed.

If the generator is not equipped with the EMCP II+, information on the engine load must be provided by a power sensor.

The power sensor output to the ECM must be an analog signal with a range of 0 to 4.8 VDC. The power sensor output must have a linear relationship with the generator output power. The accuracy of the wattmeter output must be within 1 percent of the generator actual output power.

The engine control system includes parameters that allow the ECM to estimate the generator output power. The values for these parameters are modified by using Cat ET. To identify the parameters for the wattmeter, Cat ET labels the parameters "Generator Output Power Sensor".

For details on these parameters, refer to Systems Operation, Testing and Adjusting, RENR5978, "Electronic Control System Parameters".

There are two possible configurations for the wiring for the load signal. Refer to Illustrations 14 for typical installations.

Illustration 14	g03779617
Schematic of the wiring for the load signal. The engine is not equipped with an auxiliary sensing module. For the actual wiring, refer to the generator schematic diagram. The potentiometer is optional. For further information, refer to Troubleshooting, "Generator Output Power Sensor - Set".

Inputs for the Modes of Operation

The engine control system has three active modes of operation: Start/Run, Auto, and Stop. The mode of operation is determined by three inputs on the J1 connector. A mode is activated when the terminal for the mode is connected to the digital return or to the −Battery.

Table 5 lists the valid combinations of the inputs. Combinations that are not shown in Table 5 will activate a diagnostic code. The transition between modes must occur within 1/10 second. If the transitions do not occur within 1/10 second, a diagnostic code is activated.

Illustration 15 is a schematic of the inputs and of the switched +Battery supply to the engine control system.

Illustration 15	g03779629
Schematic of the inputs for the modes of operation The slave ECM is not present on 20 cylinder engines. The Auxiliary Sensing Module is optional.

Off/Reset - When none of the inputs are connected to the digital return or to the −Battery, the engine is in the Off/Reset mode. The switched +Battery supply to the engine control system is off. Any active diagnostic codes are cleared.

Start/Run - The engine start sequence begins when terminal J6-29 is connected to the digital return or to the −Battery. Switched +Battery power is supplied to the engine control system. The engine will run until terminal J6-29 is disconnected from the digital return or from the −Battery. When terminal J6-29 is disconnected, the normal shutdown sequence is initiated. If the cooldown feature is programmed, the engine operates for the cooldown period prior to shutdown.

Auto - When terminal J6-39 is connected to the digital return or to the −Battery, the engine control system is in the AUTO mode. Switched +Battery power is supplied to the ECM. The engine will not start unless terminal J6-29 is also connected to the digital return or to the −Battery. The connection can be accomplished with a customer supplied remote start switch.

When terminals J6-29 and J6-39 are connected to the digital return or to the −Battery, the engine start sequence is initiated. The engine will run until terminal J6-29 is disconnected from the digital return or from the −Battery. When terminal J6-29 is disconnected, the normal shutdown sequence is initiated. If the cooldown feature is programmed, the engine operates for the cooldown period prior to shutdown. The engine control system will remain in the Auto mode.

In the Auto mode, terminal J6-29 is used to control both the engine start sequence and the shutdown sequence.

Stop - If the engine is running, the shutdown sequence begins when terminal J6-29 or terminal J6-39 is disconnected from the digital return or from the −Battery and terminal J6-19 is connected to the digital return or to the −Battery. If the cooldown feature is programmed, the engine operates for the cooldown period prior to shutdown. In this mode, the switched +Battery power is still supplied to the ECM.

Startup and Shutdown Control Logic

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 switch, normal stop switch, manual prelube switch, prelube oil pressure, engine speed, data link, and driven equipment.

The start/stop control is responsible for coordinating the sequence for engine start-up and shutdown. There are seven steps to the sequence:

• Off

• Prestart

• Cranking

• Run

• Cooldown

• Coast

• Postlube

Off Mode

The "Off Mode" allows the control system to be powered up with the engine in a controlled shutdown condition.

In the "Off Mode", the control ensures that the following driver circuits from the ECM are off:

• Fuel Shutoff Valve

• Starting Motor Solenoid

• Driver Circuit for the Ignition

• Service Meter

In the "Off mode", the system monitors the control command signal. The system will remain in the "Off Mode" until "Run" is requested. If a "Run" command is requested, the system will exit "Off Mode" and the system will enter "Pre-Start Mode". In the "Off Mode", it is safe to turn off power to the control.

Prestart Mode

The "Prestart mode" provides protection against cranking the engine when it could be harmful to the engine. The "Prestart mode" performs the following three tasks:

• Optional Prelube Cycle.

• Optional crank inhibit due to low temperature of the coolant water.

• Driven Equipment Crank Inhibit.

In "Prestart Mode", any control command signal other than "Run" returns the system to the "Off" mode.

Prelube Cycle and Postlube Cycle Feature

The prelube cycle applies lubricating oil to the bearings before the engine is cranked. The postlube cycle lubricates the turbocharger after the engine shuts down. Prelube must be enabled with Caterpillar Electronic technician (ET). A postlube duration time is programmable with Cat ET.

Low Coolant Water Temperature Start Inhibit

The "Low coolant water temperature start inhibit" function is optional. If the temperature of the coolant water is below the set point, an event is generated and starting is inhibited.

Driven Equipment Start Inhibit

This function allows the customer to connect a switch input to auxiliary equipment to delay starting of the engine until the equipment is ready. Monitoring a pressure switch for driven equipment is an example of this input.

Cranking Mode

This function allows the customer to connect a switch input to auxiliary equipment to delay starting of the engine until the equipment is ready. Monitoring a pressure switch for driven equipment is an example of this input.

The following steps describe the process:

1. The indicator for the run relay is energized.

2. The "Engine Purge Cycle Time" allows any unburned fuel to exit through the exhaust system prior to ignition. This helps prevent combustion in the exhaust system.

3. The driver circuit for the starter solenoid is energized. The system remains in the cranking mode until either the engine starts, or the cycle crank time is exceeded. If the cycle crank time elapses without the engine starting, the starter solenoid and the fuel shutoff valve are de-energized. The system enters the rest cycle.

4. During the rest cycle, the starter and the fuel shutoff valve remain de-energized. The system remains in the rest cycle for the cycle crank time. After the cycle crank time has elapsed, the system goes back to the fuel purge procedure. The cycle will repeat.

5. A timer starts as soon as the system enters the cranking mode. During the cranking mode, if the timer exceeds a user defined total crank time, an overcrank event is generated. This causes the system to change to the off mode.

When the engine speed exceeds a set crank terminate speed, the engine is defined as being started. The following actions take place when the crank terminate speed is achieved:

• The starter solenoid is de-energized.

• The crank terminate indicator is energized.

• The service meter is started.

• The system enters the run mode.

Run Mode

In "Run Mode", the control monitors the engine during normal operation.

Cooldown Mode

The cooldown mode allows the engine to run at a reduced load before shutdown. The system remains in the cooldown mode until the cooldown period elapses or until the control command signal changes from cooldown mode.

Coast Mode

The system monitors engine speed as the engine is coasting to a stop. In coast mode, the control monitors the engine during deceleration after the fuel has been shut off. In the coast mode, the system will generate a fault code if the fuel shutoff valve is not functioning correctly.

Postlube Mode

The postlube mode lubricates the turbocharger bearings after engine shutdown. The system runs the pump for a programmable time after shutdown to lubricate the turbocharger bearings.

Initial Start-Up Procedure

Ensure that all of these factors are in proper condition prior to the initial start-up: engine installation, driven equipment, all the related hardware, and electrical connections. Failure to perform the commissioning procedure could result in unsatisfactory operation.

Perform the following procedure for the initial start-up and for start-up after major maintenance and/or repair.

1. Verify that the connections between the engine control system and the customer equipment are connected properly.

2. If the information on the generator output power is provided by a power sensor, check the power sensor offset voltage. Refer to Troubleshooting, "Generator Output Power Readings Do Not Match". Continue with this procedure after you have minimized the power sensor offset voltage.

3. Connect Cat ET to the service tool connector. Refer to "Connecting Cat ET with the Communication Adapter Assembly".

4. Set the engine control to the STOP mode. Test each emergency stop button before the engine is started to verify that the engine control system generates an E264 event code.

   After the operation of each emergency stop has been verified, set the engine control to the Off/Reset mode.

   Note: Check the generator protective devices prior to start-up. Some of the generator protective devices can only be checked during engine operation.

5. Check the generator protective devices for proper operation.

6. Turn on the jacket water heater. Verify that the heat is set to 45 to 65 °C (113 to 150 °F).

   Note: The engine may be difficult to start if the jacket water coolant temperature is below 43 °C (110 °F).

   Note: The spark plugs may become fouled with moisture condensation if the engine is cranked and the jacket water coolant temperature is below 43 °C (110 °F).

7. Inspect the inlet air system. Make sure that the system does not leak. Make sure that the system is free of debris.

8. Inspect the fuel supply system. Make sure that the system does not leak. Make sure that the system is free of debris. Blow any debris from the fuel lines.

9. Connect a properly calibrated emissions analyzer to the exhaust stack.

10. Perform the daily inspection and all the daily maintenance procedures that are scheduled in Operation and Maintenance Manual, SEBU7681, "Maintenance Interval Schedule".

11. Set the engine control to the STOP mode. Use the "Monitoring System" screen from the "Service" drop-down menu on Cat ET to view the default settings of the trip points for the alarms. Adjust the settings, if necessary.

    For the necessary values of the operating parameters, refer to the applicable Data Sheet on engine performance in the engine Technical Marketing Information (TMI).

12. Use the "Configuration" screen from the "Service" drop-down menu on Cat ET to view the configuration parameters.

    Note: Use the data from the gas analysis provided by GERP to determine the correct settings for the "Fuel Quality" and the "Gas Specific Gravity" parameters.

    1. Program the parameters, if necessary.

       Incorrect programming of the parameters may lead to complaints about performance and/or to engine damage. For details, refer to your engine Systems Operation, Testing and Adjusting manual. Configuration parameters can be found in the Systems Operation section.

       • Systems Operation/Testing and Adjusting, KENR9737, "G3512E and G3520E Generator Set Engines"

       • Systems Operation/Testing and Adjusting, RENR5978, "G3520C and G3520E Generator Set Engines"

       Note: If the generator set is equipped with an EMCP II+ system, the "Generator Output Power Sensor Scale Factor" and the "Generator Output Power Sensor Offset" do not require programming.

13. Turn ON the fuel supply to the engine. Verify that no gas is leaking. Verify that the gas does not flow past the GSOV.
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    Unburned gas in the air inlet and exhaust system may ignite when the engine is started. Personal injury and/or damage may result. Before starting an engine that may contain unburned gas, purge the unburned gas from the air inlet and exhaust system. Refer to "Unburned Gas - Purge".

14. Start the engine.

    The engine will accelerate to low idle rpm. Operate the engine at low idle. Verify the following conditions:

    • Proper engine oil pressure

    • No fluid leaks

    • No gas leaks

    Several attempts may be required for the initial start-up before air is purged from the fuel lines.

    Note: If the engine will not start, use Cat ET to check for diagnostic codes and for event codes. Correct any active conditions before you attempt to start the engine again.

15. After the engine is running, test the operation of each emergency stop button.

    After each test, reset the emergency stop button and set the engine control to the Off/Reset mode. Then restart the engine. After all the emergency buttons have been tested, use Cat ET to clear the event codes from the ECM.

    Note: Some of the generator protective devices can be checked prior to start-up. Some of the generator protective devices can only be checked during engine operation.

16. Check the generator protective devices for proper operation.

17. Increase the engine speed to high idle rpm. Verify that the engine is stable.

    If the engine is unstable, perform the following procedure.

    1. Record the values for these parameters:

       • "Governor Gain Factor"

       • "Governor Stability Factor"

       • "Governor Compensation Factor"

    2. Set the values for the "Governor Gain Factor", "Governor Stability Factor", and "Governor Compensation Factor" parameters to zero.

    3. Adjust the "Fuel Quality" parameter until the engine becomes stable and the exhaust oxygen is approximately 4 percent. Verify that the exhaust port temperatures are below the setpoint for a warning.

    4. Adjust the primary governor. Refer to "Adjusting the Governor".

18. Select the "Information" drop-down menu to view the status parameters. Review the values of the status groups on Cat ET. Verify that the pumps for the cooling system are operating. Verify that the cooling system temperatures and the cooling system pressures are within the correct operating ranges.

19. Close the main circuit breaker for the generator to engage the generator.

    Note: When the engine load exceeds 25 percent, the air/fuel ratio control will operate in the feedback mode.

20. Slowly ramp the load up to 30 percent.

    Note: When the air/fuel ratio control is in the feedback mode, the Fuel Correction Factor (FCF) may no longer be 100 percent. The ECM may adjust the FCF to compensate for the fuel quality and for the ambient conditions.

21. Set the "Desired Emission Gain Adjustment" to a value of "100".

22. Verify that the value of the "Generator Real kW" parameter in Status Group 1 is within 1 percent of the generator output power.

    If the reading on Cat ET is not within 1 percent of the generator output power, refer to Troubleshooting, "Generator Output Power Readings Do Not Match".

    When the value of the "Generator Real kW" parameter is within 1 percent of the generator output power, continue with this procedure.

23. Slowly ramp up to 50 percent load. Allow the jacket water coolant temperature to reach 75 °C (167 °F).

24. Slowly ramp up to 70 percent load. Verify that the engine is stable.

    If the engine is unstable, adjust the auxiliary governor. Refer to "Adjusting the Governor".

25. Verify that the NO_x emissions are above the desired full load setting.

26. Slowly ramp up to 100 percent load. Verify that the engine is stable.

    If the engine is unstable, adjust the auxiliary governor. Refer to "Adjusting the Governor".

27. Verify that the value of the "Generator Real kW" parameter is within 1 percent of the generator output power.

28. Adjust the "Desired Emission Gain Adjustment" parameter to obtain the values of emissions that are required at the site.

    • To lean the air/fuel mixture, decrease the gain adjustment.

    • To richen the air/fuel mixture, increase the gain adjustment.

    A small change in the "Desired Emission Gain Adjustment" causes a large change in the actual exhaust emissions.

    Example: adjustment of 1 percent in the parameter value will result in a change of 20 to 40 ppm in the actual level of NO_x.

    When you adjust the exhaust emissions, make a small change in the value of the gain. Wait until the system stabilizes. Check the emissions again. Repeat the process until the desired emissions level is achieved.

    Use the emissions analyzer to verify that the values of emissions meet the requirements of the site.

29. Record the data from all the status groups on Cat ET. Save the data for future reference.

Adjusting the Governor

The response of the throttle actuator can be adjusted with the Caterpillar Electronic Technician (Cat ET). Use Cat ET to change these three parameters:

• "Governor Gain Factor"

• "Governor Stability Factor"

• "Governor Compensation Factor"

The default values should be sufficient for initial start-up. However, the values may not provide optimum performance.

These adjustments are provided to obtain optimum responses to changes in the load and in the speed. The adjustments also provide stability during steady state operation.

If you have a problem with instability, always investigate other causes before you adjust the governor. For example, diagnostic codes and unstable gas pressure can cause instability.

When you adjust the primary governor, make sure that the "Grid Status" parameter is "Off". When you adjust the auxiliary governor, make sure that the "Grid Status" parameter is "On".

To change the "Governor Gain Factor", the "Governor Stability Factor", or the "Governor Compensation Factor", use the "Real Time Graphing" feature on the "Information" drop-down menu of Cat ET. The graph provides the best method for observing the effects of your adjustments.

After you make adjustments, always test the stability by interrupting the engine speed and/or load. Operate the engine through the entire range of speeds and of loads to ensure stability.

Note: Adjustment of the "Governor Gain Factor" directly affects the speed of the throttle actuator when there is a difference between the actual engine speed and the desired engine speed. An excessive increase of the "Governor Gain Factor" may amplify instability.

To set the "Governor Gain Factor", increase the "Governor Gain Factor" until the actuator becomes unstable. Slowly reduce the "Governor Gain Factor" to stabilize the actuator. Observe that the engine operates properly with little overshoot or undershoot.

The adjustment of "Governor Stability Factor" dampens the actuator response to changes in load and in speed. Increasing the "Governor Stability Factor" provides less damping. Decreasing the "Governor Stability Factor" provides more damping. To reduce overshoot, decrease the "Governor Stability Factor". To reduce the undershot, increase the "Governor Stability Factor".

Note: An increase of the "Governor Stability Factor" may require a decrease of the "Governor Gain Factor" to maintain a stable operation.

Illustration 16 shows some typical curves for transient responses.

Illustration 16	g01017530
Typical response curves (Y) Engine speed (X) Time (1) The "Governor Gain Factor" is too high and the "Governor Stability Factor" is too low. There is a large overshoot on start-up and there are secondary overshoots on transient loads. (2) The "Governor Gain Factor" is slightly high and the "Governor Stability Factor" is slightly low. There is a slight overshoot on start-up but the response to transient loads is optimum. (3) The "Governor Gain Factor" is slightly low and the "Governor Stability Factor" is slightly high. There is optimum performance on start-up but slow response for transient loads. (4) The "Governor Gain Factor" is too low and the "Governor Stability Factor" is too high. The response for transient loads is too slow. (5) The response to transient loads is adjusted for optimum performance.

Decrease the "Governor Compensation Factor" until a slow, periodic instability is observed. Then, slightly increase the "Governor Compensation Factor". Repeat the adjustments of the "Governor Gain Factor" and of the "Governor Stability Factor". Continue to increase the "Governor Compensation Factor", readjust the "Governor Gain Factor" and the "Governor Stability Factor", until stability is achieved and the engine response to changes in load and in speed is optimized.

Illustration 17 is a graphic representation of adjusting the "Governor Compensation Factor".

Illustration 17	g01017541
The increased width of the line for the actuator voltage indicates that the throttle actuator is more active as the "Governor Compensation Factor" increases. (Y) Actuator voltage (X) Time in seconds

Unburned Gas − Purge

The following events cause unburned gas to remain in the air inlet and in the exhaust manifold:

• Emergency stop

• Engine overspeed

• The engine control is set to the STOP mode and the gas shutoff valve does not close.

• Unsuccessful successive attempts to start the engine

Unburned gas may remain in the air inlet and exhaust system after several unsuccessful attempts to start the engine. The unburned gas may increase to a concentration that may ignite during a successive attempt to start the engine.

Perform the following procedure to purge the unburned gas:

1. Connect Cat ET to the engine.

2. Verify that the value of the "Engine Purge Cycle" parameter is equal to 10 seconds less than the value of the "Crank Cycle" parameter.

3. Set the engine control to the START mode. The engine will crank for the "Engine Purge Cycle" time. Then, the gas shutoff valve will be energized and the ignition will be enabled. The engine will start.

4. Continue with your previous procedure.