G3600 ENGINES Caterpillar

The troubleshooting procedures in this section are to assist in the repair of intermittent problems and problems with symptoms that DO NOT have a diagnostic code. Before searching for problems or attempting to perform a repair in the Troubleshooting Symptom List, follow the bullet procedure below to understand and determine the operational problem. Operate the engine after correcting the problem and duplicate the conditions to verify the problem(s) is corrected.

* How often does the problem occur?Can the problem be recreated? If the problem is easily repeatable, note the conditions when the problem occurs.

* Has the engine been repaired previously for the same problem?If the engine has experienced the same problem, avoid replacing the same components unless absolutely sure they are the problem!

* Did the engine hesitate or misfire without a shutdown?If a shutdown occurred, did the operator have to reset the system by turning the Mode Control Switch (MCS) to the OFF/RESETposition to allow the engine to restart? Repairing the reason for the engine not restarting should repair the reason for the engine shutdown.

* Does the problem occur only at specified loads, specific engine rpm or specific operating temperatures?Does the problem occur only at specific ambient temperatures or outside weather conditions?

Operate the engine under similar conditions while attempting to duplicate the problem.If possible, troubleshoot the problem within those conditions. Check programmed parameters affected by operating conditions to verify the programmed parameters are not the problem! Inspect each value, one at a time, to verify the problem is corrected.

Engine Prelube Pump Inoperative or Slow

Probable root causes:

* Low air (or gas) supply pressure to prelube pump

* Prelube Control System wiring circuit and relays

* Prelube Control Valve

* Prelube Relay Valve

* No lubrication to prelube pump

* Inspect Air or Electric Prelube Motor

* Replace Motor

Perform the following tests in order:

1. Low air (or gas) supply pressure to prelube pump Check supply system for leaks and pressure.

2. Prelube Control System wiring circuit and relaysCheck wiring circuit, repair as needed.

3. Prelube Control ValveInspect and repair as needed.

4. No lubrication to prelube pumpInspect, repair the lubricator and/or fill with proper lubricant.

5. Inspect Air or Electric Prelube MotorInspect and repair as needed.

6. Prelube Pump failureCheck for seizure of pump. Inspect and repair as needed.

7. Prelube Pump ExhaustCheck for restriction of prelube pump exhaust.

Engine Prelubes, but Engine Does Not Crank

Probable root causes:

* Customer inputs to ESS Panel

* Prelube Pressure Switch Wiring Circuit

* Starter motor failure (stuck)

* Time Delay Relay (Faults or set wrong)

Perform the following tests in order:

1. Customer inputs to ESS PanelCheck Driven Equipment Ready Signal. The DDT will indicate the status of the Drive Equipment Ready signal. Check initiate contact signal. (The DDT will indicate the status of the initiate contact signal).

NOTE: ESS panel relay chatter indicates that the ground signal to the Driven Equipment Ready or initiate contact input may be intermittently opening.

2. Prelube Pressure Switch Wiring CircuitCheck wiring circuit to prelube switch. Check prelube pressure switch. Check prelube pressure switch relay base or relay, terminal-9 on the SCM should be pulled to ground to initiate starting motor cranking. (There will be 10 VDC to 13 VDC at terminal-9 on the SCM when the ESS panel is powered up and PLPSR relay has not closed to initiate cranking).

There are two different Prelube Pump Switch time delays used. The early design (163-3266) uses the following settings:

* Timing Function 1 at 50 sec.

* Timing Function 2 set to Release

* Timing Adjust Potentiometer at 1.5 sec

See Engine News SEBD 9282-00 Feb 2000.

The late style (168-7823) uses the following settings:

* Pot A-40%

* Rotary Switch Opening B1 at 30 sec

* Rotary Switch C at B (note: Do not select B; a B followed by a dot).

See Engine News SEBD 9289.00 Sept 2000.

3. Refer to the Start Logic Flow Chart in the Systems Operation Testing and Adjusting Manual for your engine.

4. Mode Control Switch WiringCheck mode control switch wiring to status control module. Check initiate contact and driven equipment ready circuits.

5. Inspect starter motor and pinion insure that pinion operates and is free. Check barring device to insure it is not engaged. Use manual value on starter motor solenoid to try and rotate starter motor.

Air Starting Motor Does Not Turn

Probable root causes:

* Starting Pinion already engaged (stuck).

* Starting system wiring circuit or relay

* Low air (or gas) supply pressure to starting motor

* Air Start Control valve

* Worn or failed starting motor (vane type) parts

* Air leakage from Starting Motor (vane type)

* Engine barring device

* Starting motor (vane type) lubricator not working correctly

* Air start pneumatic relay

Perform the following tests in order:

1. Starting system wiring circuit or relay.

Check wiring circuit, repair as needed.

2. Low air (or gas) supply pressure to starting motor

Check supply system for leaks. Check operation of the air compressor. Check adjustment of the air (or gas) pressure regulator. Air supply tank too small or blockage in air supply lines to the starting motor.

3. Air Start Control

Inspect and repair as needed.

4. Worn or failed starting motor (vane type) parts

Disassemble the motor and inspect the parts. A guide for determining worn parts that cannot be used again follows.

Install a set of new vanes if any vane is cracked, damaged or worn to the extent that its width is less than 32mm (1.25 in) at either end. Replace rotor bearings if any roughness or looseness is apparent in the bearings. Replace rotor if the body had deep scoring that cannot be removed with the use of emery cloth. Replace cylinder if there are any cracks or deep scoring. Clean up end plate scoring with emery cloth, place on a flat surface.

5. Air leakage from Starting Motor (vane type)

Check the motor for worn seals. Plug the exhaust. Apply 250 kPa (37 psi) air to the inlet and submerge the unit in water for 30 seconds. If bubbles appear, make a replacement of the motor seals.

6. Engine barring device

Check barring device to insure that it is fully disengaged. Check interlock air lines and fittings to insure that there is no leakage.

7. Starting motor (vane type) lubricator not working correctly

Check the lubricator, inlet hose, fitting and oil supply hose to make sure they are vacuum tight and free of leaks. Clean, make adjustments, tighten all fittings, fill lubricator or make a replacement, if necessary.

Check for seal leaks, control line removed or plugged, or debris in valve or valve stuck.

Electric Starting Motor Does Not Turn

Probable root causes:

* Starting system wiring

* Low supply voltage to starting motor

* Faulty starting motor solenoid

* Faulty starting motor

Perform the following tests in order:

1. Starting system wiring

Check wiring circuit, repair as needed. Check starting motor relay.

2. Low supply voltage to starting motor

Check condition of battery. Charge battery or make replacement as necessary. Check condition of starter cables and terminals.

3. Faulty starting motor solenoid

Inspect and repair as needed.

4. Faulty starting motor

Inspect, make repair or replacement of starting motor as needed.

5. Customer Inputs

Check initiate contact and driven circuits.

Electric Starting Motor Pinion Does Not Engage With The Flywheel

Probable root causes:

* Butt engagement of pinion with flywheel ring gear

* Broken starting motor clutch jaws or other parts

* Dry starting motor pinion shaft

* Barring device engaged

Perform the following tests in order:

1. Butt engagement of pinion with flywheel ring gear

Manually rotate starting motor pinion and attempt restart.

2. Broken starting motor clutch jaws or other parts

Replace the parts.

3. Dry starting motor pinion shaft

Remove the drive pinion and put clean grease on the drive shaft splines and drive pinion.

4. Barring device engaged

Interlock control lines are broken, disconnected, or ruptured.

Starting Motor Runs, Pinion Engages, But Does Not Turn The Flywheel

Probable root causes:

* Engine or driven equipment

* Accessory equipment (hydraulic pump, air compressor, etc)

Perform the following tests in order:

1. Engine or driven equipment

Use barring device to determine if the engine can be turned. If the engine cannot be turned, remove the spark plugs and check for fluid in the cylinders. If fluid in the cylinders is not the problem, disconnect coupling to the driven equipment and try rotating the engine. If the engine will not rotate, it must be disassembled to check for other internal failures. The valves may be contacting the pistons, or there is a piston seizure, bearing seizure, crankshaft failure or driven equipment problem.

2. Accessory equipment (hydraulic pump, air compressor, etc)

Disconnect the driven equipment until faulty accessory can be found. Repair or replace the faulty accessory.

Engine Will Crank But Will Not Start

Probable root causes:

* Secondary Ignition system failure

* Primary Ignition system failure

* No fuel (gas) to engine

* Faulty Fuel Actuator, control valve, linkage and/or prechamber needle valve

* Slow cranking speed

* Incorrect Air-to-Fuel Ratio during cranking

* Misfiring Cylinders

* Supply power to actuators

* Engine is cold

* Run Relay to ECM does not open

* Hydrax pressure switch open

* Actuators don't move

Perform the following tests in order:

1. Secondary Ignition system failure

Check the spark plugs for moisture. Inspect for combustion gas leaks and/or cracked porcelain. Check and set gap of the plugs. Install new plugs and plug gaskets if worn or damaged. Check type of plug used. Check the ignition transformers for loose connection, moisture, short or open circuits.

2. Primary Ignition system failure

During cranking, the ignition system begins firing at 50 rpm (an actual ignition timing of approximately 28 degrees BTC should be displayed on the DDT).

Use a 9U-6958 Magneto Peak Detector tool to confirm primary voltage at 170 to 200 VDC. On Mag Engines use timing light on primary wiring to confirm ignition signal to the ignition transformers (or us 9U6695 Ignition Indicator to confirm ignition signal to the transformers). If the problem is with the primary voltage possible causes are a failed Caterpillar Ignition system, (CIS) failed timing control module (TCM), faulty ignition wiring harnesses, spark plug electrodes shorted together or transformer shorted to ground, failed magneto, failed fuse or relay in SCM, (ESS ignition system Diagnostic Codes 501-09 through 506-09, are disabled until engine speed is greater than 350 rpm for 30 seconds).

3. No fuel (gas) to engine

During cranking the Fuel Actuator should starting opening at 50 rpm and the fuel manifold pressure shown on the DDT should vary between 1 to 5 kPa (0.14 to 0.72 psi). Actuator position should vary from approximately 5 percent open to 10 percent open during cranking. If Actuator position during cranking is greater than 30 percent open, check the fuel supply pressures. Check prelube ready light. If the prelube ready relay drops out during crank, the engine may not start. Check the prelube ready circuit, wiring, switch, relay and relay base.

Check gas supply line shutoff valve and shutoff valve solenoid, wiring circuit, and SCM fuses and relay. Check gas pressure regulator, check inlet and outlet regulator pressure. Check Fuel filter.

4. Faulty Fuel Actuator, control valve, linkage and/or prechamber needle valve

Check the Fuel Actuator linkage to confirm that the control valve is completely closed when the Actuator is in the closed position. (To prevent flooding of the engine during starting, the Fuel Actuator position should be approximately 10 percent when the fuel valve is in the closed position). Check that the Actuator permits the fuel control valve to open. Replace failed Fuel Actuator. Check Fuel Actuator linkage to insure that it operates smoothly.

Check prechamber needle valves. (On approximately 900 BTU fuel the recommended setting of the needle valve is 3 to 5 turns open on a "green" engine, prior to prechamber turning).

5. Slow cranking speed

Cranking speed must be greater than 80 rpm starting speed. Check condition of starting system, air supply pressure and starting motor.

Incorrect Air-to-Fuel Ratio during crankingWhile cranking, adjust BTU potentiometer setting to provide between 1 to 5 kPa (0.14 to 0.72 psi) fuel manifold pressure as displayed on the DDT.

6. Check Inlet Manifold Pressure readingdisplayed on CMS gage #4, the reading should be within .3 psi (2 kPa) of the ambient atmospheric pressure (when the engine is stopped). If necessary, perform Pressure Module Calibration Procedure, refer to System Operation, Test & Adjust Manual.

7. Misfiring CylindersCheck choke plate position., During cranking, the choke plate should be at the full open position. The orientation of the choke plate is represented by the groove on the end of the choke plate shaft. Monitor the exhaust port temperatures and combustion burn times to identify misfiring cylinder. Refer to Intermittent Misfire topic in the manual for troubleshooting information. Be sure the needle valves are not closed off or open too far (should be between 2 to 7 turns open).

8. Supply power to actuatorsCheck SR2 relay and Fuel Actuator fuse.

9. Engine is coldRefer to minimum starting temperature in the G3600 Application and Installation manual.

10. Run Relay to ECM does not openTurn the Mode Control Switch to the STARTposition. Measure voltage of circuit M112/YL at terminals 220 or 535. The voltage should measure greater than 0 volt DC. If the voltage is 0, replace the SCM or Relay.

CMS Panel Display Engine Package Shutdown

Not working correctly or Err displayed on CMS and/or DDT display indicating diagnostic codes E2 or E6.

Probable root causes:

* 24 VDC power supply of ground bus connection to ESS panel

* CAT Data Link #2 circuit problem

* Failed DDT or DDT harness

* Failed DMC module

* Failed CMS module

NOTE: To clear the Err message displayed on the CMS, turn the mode control switch to the OFF/Resetposition.

Perform the following tests:

1. Active diagnostic code

Check for an active diagnostic code displayed on the ECM. If a code is present correct the problem.

2. 24 VDC power supply or ground buss

Check all power and ground connections in the ESS panel.

3. Failed DDT or DDT harness

Disconnect the DDT and harness from the data link. If the diagnostic clears, refer to DDT troubleshooting in this manual.

4. CAT Data Link #2 circuit problem

Check all connections in the data link #2 circuit in the ESS panel and Junction box. Circuit number D101/WH and circuit number D101/BK. Check the resistor in the Junction box terminals 914 and 915. See data link failure in this manual.

NOTE: The Cat Data Link Shield Wire (D101/SH) from terminal 912 in the Engine Junction Box should NOT be terminated in the ESS Panel.

Probable root causes:

Loss of initiate contact signal to ESS panel with MCS in Automatic (remote start) modeESS Panel will not power down after engine shutdownRelayBad contact on Hydrax pressure switchBad engine oil pressure switchBad time delay relay conflict

Perform the following tests in order:

1. Loss of initiate contact signal to ESS panel with MCS in AUTOmatic (remote start) mode Check wiring circuit for start initiate contact signal to customer connection terminal. The engine will shutdown, with no diagnostic code, if start initiate contact signal is open to ground. The status of the start initiate contact signal is displayed on the DDT.

2. ESS Panel will not power down after engine shutdownEngine postlube cycle ongoing. Postlube cycle of one to three minutes is typically programmed into the Personality Module. Check state of postlube relay (PLR) and prelube wiring circuit. The DDT display will indicate the status of the prelube switch and the prelube relay.

3. Relay

Check operation of SR1 and PLPSR relay. If the relay is not operating correctly replace the relay.

Heinzmann Actuators Have High Frequency, Low Amplitude Oscillation

Probable root causes:

Electrical noise from one of the Actuators is affecting the command signal to the remaining two Actuators.

Perform the following tests in order:

1. Electrical noise

Identify the failed Actuator by placing the ESS panel Mode Control Switch (MCS) in the STOP position and prelubing the engine so that the Actuators are powered up, then remove the fuses from the 24 VDC circuit to the Actuators one at a time. When the Actuators stop oscillation, replace Actuator respective to the fuse which stopped oscillation. Refer to wiring schematic for the engine control system.

Short Spark Plug Life

Probable root causes:

* Faulty Spark Plugs

* Incorrect Spark Plug

* Incorrect Air-to-Fuel Ratio

* CIS double strike

* Spark plug gap

Perform the following tests in order:

1. Faulty Spark Plugs

Inspect spark plug wear, combustion gas leaks and/or cranked porcelain. The resistance level of the spark plug should be between .5k and 1.4k. Set gap on used spark plugs or install new plugs and plug gaskets if used plugs are worn or damaged.

NOTE: Always use a new spark plug gasket when plugs are removed and installed. Spark plug torque is 68 N-M (50 lb ft).

2. Incorrect Spark Plug

Check type being used. Install correct type.

3. Incorrect Air-to-Fuel Ratio

Perform Prechamber Calibration procedure (refer to System Operation, Test & Adjust Manual).

4. CIS double strike

Check to see if the CIS double strike is enabled.

5. Spark plug gap

Check the spark plug gap. Repair as required.

Ignition Timing Unstable

Probable root causes:

* Poor interface signals between TCM and MIB or TCM and CIS

* Crank angle signal

* TCM or ECM engine speed signal

* Engine rpm or load or timing is not stable Detonation

* Failed resistor in Engine Junction Box

* Electrical noise

Perform the following tests in order:

1. Poor interface signals between TGM and Ignition System

Check the actual timing and desired timing on the DDT Service Tool. If the actual ignition timing is unstable and the desired ignition timing is stable, a faulty ignition system may be the cause. Use the DDT to operate the engine in Magneto Calibration mode. If the timing stabilizes, inspect the CIS and TCM portion of the ignition system. If the displayed timing is unstable in Magneto Calibration (MAG CAL) mode, the cause may be a poor crank angle signal or failed magneto.

2. Crank angle signal

Clean debris from bottom of Crank Angle Sensor and from outside diameter of flywheel. Check for damage to Crank Angle Sensor. Check for damage to flywheel surface. Adjust depth of sensor to provide proper distance between flywheel and end of the sensor by turning sensor counterclockwise 1/2 to 3/4 turn. Check continuity/polarity of crank angle sensor wiring circuit. Refer to the System Operation Testing and Adjusting Manual.

3. TCM or ECM engine speed signal

Clean debris from bottom of TCM and ECM speed pickups and from the heel ring gear teeth. Check for damage to the speed pickups and the heel ring gear teeth. The heel and the end of the sensor by turning sensor counterclockwise 1/2 to 3/4 turn. Check TCM and ECM speed pickup wiring circuit. Refer to the Systems Operation Testing and Adjusting Manual.

4. Engine rpm or load or timing is not stable

The ESS control determines the desired (ideal) ignition timing based on engine speed and calculated fuel consumption (engine load). Therefore, if the engine is unstable, the desired ignition timing will be unstable actual ignition timing.

5. Detonation

If detonation has occurred, the desired ignition timing will be retarded as much as 6 degrees depending on the severity of the detonation. If detonation is not ongoing, the timing will return to the desired timing at a rate of one degree per minute.

6. Failed resistor in Engine Junction Box

Check resistor between Junction Box terminals 143 and 145 on early magneto engines, 790 and 791 on later magneto engines, and 789 to 790 and 791 on later engines equipped with CIS.

7. Electrical Noise

Check for electrical noise from the 24 VDC supply to the ESS panel.

Engine Speed Limited to 550 rpm/Engine Will Not Accelerate

Probable root causes:

* Input signal for Idle/Rated speed is open

* 2301 Speed Control relay contact is open

* High idle adjustment incorrect

* Excessive Load

Perform the following tests in order:

1. Input signal for Idle/Rated speed is opencheck Customer Input as ESS terminal-364 for Idle/Rated Speed to verify that it is connected to ground.

2. 2301 Speed Control relay contact is open

Check SCM set point for 2301 speed control relay to ensure proper adjustment. Refer to System Operation, Testing & Adjusting Manuel. Inspect 2301 speed control relay and fuses.

3. High idle adjustment incorrect

Use the DDT to verify high idle setting. The setting should be set to rated engine rpm. Screen 30 on DDT.

4. Excessive Load

Reduce the starting load.

Engine Lugs when Operating in "Magneto" Calibration Mode

Probable root causes:

Insufficient air flow

Perform the following tests in order:

1. Insufficient air flow

Check linkage on the air choke Actuator for smooth operation and correct adjustment. Use DDT to adjust choke plate position, refer to Choke Trim Procedure in System Operation, Testing & Adjusting Manual.

Magneto Engines

Engine speed is unstable and oscillates between 300 to 500 rpm.

Probable root causes:

Failed Magneto Interface BoxFailed Magneto back plate

Check ignition timing using the DDT. If timing goes to zero when the engine speed passes 500-rpm, the MIB or magneto back plate may have failed.

Engine Stalls at Low Load or rpm/Poor Load Acceptance

Probable root cause:

* Air Choke Actuator adjustment or Air Choke Actuator system not working

* Low Gas Pressure, gas line pressure regulator failure.

* Incorrect Air-to-Fuel Ratio

* Fuel Actuator adjustment

* Fuel valve damaged or stem packing loose

* Incorrect valve lash adjustment

* Incorrect GAV Lash Adjustment

* 24 VDC supply to ESS panel

* Ignition system failure

* Air induction system

* Exhaust bypass system failure

* Turbocharger has carbon deposits or other causes of friction

* Improper High Idle Setting on Gen Set

Perform the following tests in order:

1. Air Choke Actuator adjustment or Air Choke Actuator system not working

Check linkage on the Air Choke Actuator for smooth operation and correct adjustment. Confirm proper Choke Trim by observing the position of the Wastegate plate. With the engine running, if the Wastegate butterfly plate is either fully open or fully closed, the choke plate position needs to be adjusted. With the engine running, the ideal position for the Wastegate plate is between 25 and 75 percent open. Use DDT to adjust choke plate position. Refer to the Systems Operations, Testing & Adjusting Manual.

2. Low Gas Pressure, gas line pressure regulator failure

Check for leaks in gas supply. Check the line pressure regulator, shutoff valve and solenoid. If two or more engines are used, be sure the common supply line is large enough.

Regulator pressure should not change over the normal load range. Inspect the regulator diaphragm for leaks and valve for correct seat contact. Check gas pressure before and after the line pressure regulator. Check for restriction in the line from the regulator outlet to the inlet of the engine. Check and clean fuel filter. Replace if needed.

3. Incorrect air-to-fuel ratio

Perform Prechamber Calibration Procedure; refer to the Systems Operations, Testing & Adjusting Manual.

4. Fuel Actuator adjustment

Use DDT to adjust Fuel Actuator response characteristics, by adjusting the Gain, Compensation and Stability values, refer to the Systems Operation, Testing & Adjusting Manual.

5. Fuel valve damaged or stern packing loose

Inspect fuel valve. Tighten packing of fuel control valve.

6. Incorrect valve lash adjustment

Make adjustment by performing procedure in the System Operation, Testing & Adjusting Manual.

7. 24 VDC supply to ESS panel

Electrical noise on the power supply to the ESS can cause the engine to be unstable. Provide between 21 and 27 VDC with a variation of no more than 0.5 VDC to the ESS panel.

8. Ignition system failure

Low primary voltage can cause unstable combustion. Use 9U-6958 Magneto Peak Detector tool to confirm primary voltage at 180 to 200 VDC at both sides or circuits of the magneto. Check for primary voltage of 170 to 200 VDC in the CIS.

9. Use timing light on the primary wiring to confirm ignition signal to the ignition transformers. If an incorrect primary voltage is found, possible causes are a failed CIS, failed TCM, failed magneto, faulty ignition system wiring harnesses, spark plug electrodes shorted together or transformer shorted to ground.

NOTE: ESS Ignition system Diagnostic Codes 501-09through 506-09,are disabled until engine speed is greater than 350 rpm for 30 seconds.

10. Air induction system

Check air cleaner for restriction. Check inlet manifold for air leaks.

11. Exhaust bypass system failure

Inspect bypass system bellows for exhaust leak. Inspect Wastegate shaft and bearings. Inspect Wastegate actuator linkage.

12. Turbocharger has carbon deposits or other causes of friction

Inspect and repair turbocharger as necessary.

Intermittent Misfire, Engine Running Rough

Probable root causes:

* Misfiring cylinder

* Incorrect Air-to-Fuel Ratio

* Faulty spark plug

* Failed ignition transformers

* Failed Magneto Shutdown Relay (MSR) relay

* Low magneto output voltage

* Prechamber check valve

* Assembly alignment with the prechamber on the ignition body

* Jacket Water leak into combustion chamber Blockage of prechamber fuel supply, Excessive Load

Perform the following tests:

1. Misfiring cylinder

Identify misfiring cylinder. Check the ECM for diagnostic codes and inspect exhaust port temperature.

When engine load is greater than 50 percent, 501-02 through 516-02Diagnostic Codes will appear for cylinder that have a misfire rate that is greater than 20 percent.

When engine load is less than 50 percent, use the DDT to place engine in Prechamber Calibration Mode. In PC-CAL mode, the 501-02 through 516-02Diagnostic Codes indicates that a 20 percent misfire rate is enabled.

Use the DDT to place the engine in Prechamber Calibration Mode and press the ALT2button. This converts the displayed actual Burn Time for the individual cylinders from an averaged value to a non-averaged value. A misfire has occurred if the displayed burn time is greater than 14 milliseconds.

2. Incorrect Air-to-Fuel Ratio

Operate the engine with a different air-to-fuel ratio to determine if the misfire rate can be affected. Use the DDT to place the engine in PC CAL Module. Adjust the Fuel Energy Content potentiometer to change air-to-fuel ratio. Monitor engine stability. If misfire rate changes, perform PC CAL procedure. Adjust Choke using Choke Trim screen on the DDT. Perform Prechamber Calibration procedure.

3. Faulty Spark Plug

Inspect spark plug for wear, combustion gas leaks and/or cracked porcelain. If oil is found on plug or in shield tube, replace the shield-tube o-ring, replace plug gasket. Inspect, and if necessary, clean plug sealing surface in cylinder head using 9U-7506 Spark Plug Thread Service Tool. Install new plugs and plug gaskets if worn or damaged. The resistance level of the spark plug should generally be between .5k and 1.5k Ohms.

4. Failed Ignition Shutdown Relay

(Magneto Shutoff Relay on Magneto Engines Ignition Shutdown on CIS Engines). Check relay and SCM fuse. The ignition shutoff relay must be closed to fire the magneto or CIS.

5. Low "Magneto" Output Voltage

Use 9U-6958 Magneto Peak Detector tool to confirm primary voltage at 180 to 200 VDC. Use timing light to confirm primary ignition signal to the transformer, or use 9U-6695 Ignition Indicator to confirm ignition signal to the transformers.

6. Failed Ignition Transformer

Misfire may be a result of a failed ignition Transformer. While a transformer may function satisfactorily at light loads, it may still be the cause of a misfire at full load. Checking exhaust port temperatures will indicate which transformer is suspect. Ignition Transformers may be checked with the engine running under load by measuring the transformer case temperature. If a transformer is found to be 20°C (68°F) hotter than others on the engine it should be replaced. Transformer resistance may be measure with an Ohmmeter. Resistance measurements will vary greatly with temperature. The following values should be obtained with the transformer at 21°C (70°F).

Primary resistance is measure from terminal A to B. Disconnect wires from the transformer before making resistance checks. Secondary resistance is measured from the terminal cup to the negative terminal. Any transformers found that do not provide these results should be replaced. Make sure all connections are snug but not over torqued. All terminals should be cleaned with solvent and a light abrasive, such as a pencil eraser. Keep the flange free of dirt and debris to assure a satisfactory ground circuit. Ignition transformers should be checked visually for cracks in the case. Also check the transformer for flange separation from the case if either condition exists, replace the transformer.

7. Prechamber Check Valve

Inspect check valve for blockage of outlet and inlet passageways. Inspect check valve for evidence of combustion leak on outside of check valve body. Inspect for free ball movement in check valve. Clean with 8T-0911 solvent or replace as needed. During engine operation, check temperature of prechamber supply tube. High temperature of the supply tube indicates combustion leakage. Perform leak down test on check valve. Refer to System Operation, Testing & Adjusting Manual.

8. Assembly Alignment with the Prechamber On The Ignition Body

Remove spark plug and view the spark plug hole in the prechamber. If the spark plug hole is off center, remove, inspect and reinstall the prechamber.

Show/hide table

NOTICE
To prevent damage to the cylinder liner, siphon coolant from the combustion chamber and start engine as soon as possible.

9. Jacket Water Leak into Combustion Chamber

Check spark plug and prechamber check valve for evidence of coolant leak (crystalline deposits). Check for failed prechamber gasket seal, clean and inspect the prechamber sealing surfaces, install new gaskets. Check for proper orientation of the locating pin between the prechamber and the ignition body. Check for Jacket water leak at the cooling insert in the bottom of the cylinder head.

10. Blockage of Prechamber Fuel SupplyCheck prechamber supply needle valve and supply line for blockage.

11. Excessive Load

Reduce engine load.

NOTE: Misfire can be in two forms and they are, true misfire and indicated misfire. To some extent the exhaust port temperature will provide some insight into differentiating between these two forms. If the exhaust port temperature is low, then true misfiring is occurring, and troubleshooting can focus on those components likely to be causing it. This list should include:

* Prechamber Check Valve

* Spark Plug Spark

* Plug Extender Ignition

* Ignition Coil

* Combustion Buffer

* Prechamber Needle Valve Setting

* Prechamber Gas Supply Line

* Gas Admission Valve Setting

Engine Unstable, Sudden Changes in Engine Speed (rpm)

Probable root causes:

* Desired Speed input

* Input signals from the engine to the ECM

* Ignition system

* Fuel, Wastegate or Air Choke System

* Fuel pressure unstable

* Excessive Load

* Hydrax actuator solenoid valve

Perform the following tests in order:

1. Check Stability of Desired Speed Customer Input Signal to ESS Panel

Check stability of 20 volt supply to Desired Speed Buffer and Fuel Energy content (BTU) buffer.

2. Check Stability of Input Signals from the Engine to the ECM that are used to control air-to-fuel ratio

Check the following:

Fuel pressure and fuel temperature input signals to the ECM.

Inlet manifold pressure and inlet manifold temperature input signals to the ECM.

Fuel energy content setting input signal to the ECM.

Desired engine rpm input signal to the ECM.

3. Ignition System

On magneto engines, use a 9U-6958 magneto peak detector tool to confirm primary voltage of 180 to 200 VDC.

On CIS engines, use a 149-4235 display module to proper operation.

4. Fuel, Wastegate or Air Choke System Not Functioning CorrectlyUse the DDT to adjust Fuel Actuator response characteristics, by adjusting the governor Gain Compensation and Stability values. Refer to the Systems Operations, Testing & Adjusting Manual.

5. Fuel Supply Pressure Unstable

Check fuel supply pressure. Pressure reading should be 310 kPa ± 14 kPa (45 ± 2 psi).

7. Hydrax Actuator Solenoid

Ensure proper operation of driver module and ECM. Current signal from driver to solenoid ranges from 0.0 to 2.0 Amps for a 0 to 100% ECM.

8. Check Hydrax Pressure

The pressure reading should be 1448 to 1724 kPa (210 to 250 psi).

9. Check Actuator Rod Ends For Wear

Check the Actuator rod ends for wear.

Exhaust Port Temperature Is Too High

Show/hide table

NOTICE
To prevent engine damage, the exhaust port temperature from an individual cylinder should be no more than 40°C (72°F) higher than the average port temperature on the engine at greater than 50 percent load.

Probable root causes:

* Failed Thermocouple or Thermocouple wiring

* Incorrect air-to-fuel ratio on the individual cylinder

* Exhaust Valve failure

* Improper ignition timing on that cylinder

Perform the following tests in order:

1. Failed Thermocouple or Thermocouple Wiring

Move thermocouple to different cylinder or move to different pyro connection to confirm accuracy.

2. Incorrect Air-to-Fuel Ratio on the Individual Cylinder

Check adjustment of the gas admission lash.

3. Exhaust Valve failure

Perform compression check on cylinder. Refer to Systems Operation, Testing & Adjusting Manual.

4. Improper Ignition Timing on That Cylinder

Inspect the Actual and Desired timing using the DDT. A scope is required to check individual cylinders.

Exhaust Stack Temperature Is Too High

Probable root causes:

* Faulty signal from air-to-fuel pressure module circuit

* Air inlet system has a leak

* Incorrect air-to-fuel ratio

* Air inlet or exhaust system has a restriction

* Incorrect air choke adjustment

Perform the following tests in order:

1. Faulty Signal from Air-to-Fuel Pressure Module Circuit

Check calibration of Pressure Module, Inlet Manifold Pressure reading displayed on CMS Gauge #4 should be within 2 kPa (0.3 psi) of the barometric pressure. Refer to Systems Operation, Testing & Adjusting Manual for Pressure Calibration procedure.Check Pressure Module wiring circuit. Replace failed Pressured Module.

2. Air Inlet System Has A Leak

Check pressure in the air inlet manifold (plenum). For restrictions at the air cleaner and correct any leaks.

3. Incorrect Air-to-Fuel Ratio

Perform Prechamber Calibration Procedure. Refer to Systems Operation, Testing & Adjusting Manual.

4. Air Inlet or Exhaust System Has A Restriction

Remove the restriction.

5. Incorrect Air Choke Adjustment

Lubricate and adjust air choke linkage. Refer to Systems Operation, Testing And Adjusting Manual.

6. Improper Ignition Timing on That Cylinder

Inspect the Actual and Desired timing using the DDT for Cylinder No. 1. A scope is required to check individual cylinders.

Exhaust Emission Too High, Fuel Consumption Too High

Probable Root Causes:

* Incorrect Air-to-Fuel Ratio

* Fuel system leaks

* Improper Ignition Timing on that Cylinder

* Improper Valve/GAV Settings

Perform the following tests in order:

1. Incorrect Air-to-Fuel Ratio

Check Gas Admission Valve (GAV) lash setting. Perform Prechamber Calibration procedure.

2. Fuel System Leaks

Replacement of parts as needed at the point of leakage.

3. Improper Ignition Timing on That Cylinder

Inspect the Actual and Desired timing using the DDT for Cylinder No. 1. A scope is required to check individual cylinders.

4. Improper BTU Setting

While cranking, adjust BTU potentiometer setting to provide between 1 to 5 kPa ( 0.14 to 0.72 psi) fuel manifold pressure as displayed on the DDT.

Loud Noise (Clicking) From Under Cylinder Head Cover (Valve Area)

Probable Root Causes:

* Improper valve lash

* Damaged valve, valve spring(s), locks or valve Rotocoil

* Not enough lubrication

* Camshaft followers worn or damaged

* Camshaft worn or damaged

* Rocker arm worn at face that makes contact with bridge

* Bridges for valves worn/incorrect adjustment

* Worn push rods

* Loose or broken rocker shaft retaining bolt

Perform the following tests in order:

1. Incorrect Valve Lash

Make adjustment to the valve lash by following the procedure in the System Operation, Testing & Adjusting Manual.

2. Damaged Valve, Valve Spring(s), Locks or Valve Rotocoil. Inspect and replace parts where necessary.

3. Not Enough Lubrication

Check lubrication in valve compartment. Oil passages must be clean.

4. Camshaft Followers Worn or Damaged

Replace camshaft followers. Inspect camshaft for wear or damage. Check for free movement of valves or bent valve stem. Make required repairs.

5. Camshaft Worn or Damaged

Check for free movement of valves or bent valve stems. Replace camshaft and valve lifters.

6. Rocker Arm Worn at Face That Makes contact With Bridge

Inspect and replace parts where necessary.

7. Bridges For Valves Worn/Incorrect Adjustment

Make an adjustment or replacement as necessary.

8. Worn Push Rods

Inspect and replace parts when necessary.

9. Loose or Broken Rocker Shaft Retaining Bolt

Check for free movement of valves. Repair or replace as necessary.

Mechanical Noise (Knock) in Engine

Probable Root Causes:

* Failure of bearing or connecting rod

* Damaged timing gears

* Attachment or auxiliary component failure

* Damaged crankshaft

* Detonation

Perform the following tests in order:

1. Failure of Bearing for Connecting Rod

Inspect the connecting rod bearing and the bearing surface on the crankshaft. Inspect oil filter for bearing debris. Install new parts where necessary.

2. Damaged Timing Gears

Install new parts where necessary.

3. Attachment of Auxiliary Component Failure

Repair or install new components.

4. Damaged Crankshaft

Install a new crankshaft.

5. Detonation

Inspect the detonation level on the DDT.

Too Much Engine Vibration

Probable Root Causes:

* Alignment of engine to driven equipment

* Engine supports are loose, worn, or have improper bolt torque

* Drive coupling

* Vibration damper loose or leaking

* Driven Equipment is out of balance

Perform the following tests in order:

1. Alignment of Engine to Driven Equipment

Check alignment.

2. Engine Supports are Loose, Worn, Or Have Improper Bolt Torque

Tighten all mounting feel hold down bolts. Check mounting feet push bolts, they should not be touching the sides of the mounting feet. On generator set packages, check setting of vibration isolator snubber bolts. Refer to LEKQ2459, Gas Engine Application and Installation Guide for Mounting, Alignment, Vibration and Noise, and SEHS7654, Alignment Special Instruction for information.

3. Drive Coupling

Inspect/Repair coupling.

4. Vibration Damper Loose or Leaking

Check vibration damper for damage or fluid leakage. Tighten bolts. If vibration damper bolt holes have damage or wear, replace with new parts.

5. Driven Equipment Is Out Of Balance

Check balance, perform corrections as needed.

Engine Is Experiencing Early Wear

Probable Root Causes:

* Dirt in Lubrication oil or extended oil change interval

* Dirt in fuel supply

* Dirt in air system

Perform the following tests in order:

1. Dirt in Lubrication Oil

Remove dirty lubrication oil. Install a new oil filter element. Put clean oil in the engine.

2. Dirt in Fuel Supply

Remove dirty fuel filter and install a new filter.

3. Dirt in Air System

Remove dirty air filter and install new air filter.

Engine Has High Oil Pressure

Probable Root Causes:

* Restriction in lube system

* Faulty priority valve

* Faulty oil pressure relief valve

* Incorrect viscosity oil used

Perform the following tests in order:

1. Restriction in Lube System

Use various pressure taps to determine failure of blockage. Repair as necessary.

2. Faulty Priority Valve

Inspect priority valve and replace damaged or worn parts.

3. Faulty Oil Pressure Relief Valve

Inspect and repair oil pressure relief valve as necessary.

4. Incorrect Viscosity Oil Used

Drain engine oil and refill with correct viscosity oil. Install new oil filters.

Engine Has Low Oil Pressure

Probable Root Causes:

* Oil level low

* Faulty Oil Pressure Sensor

* Dirty oil filter or oil cooler

* Too much clearance between rocker arm shaft and rocker arms

* Oil pump suction screen is dirty

* Oil pump pressure regulating valve does not close

* Faulty oil pump

* Too much clearance between crankshaft and crankshaft bearings

* Too much clearance between camshaft and camshaft bearings

* Broken piston cooling jet

Perform the following tests in order:

1. Oil Level Low

Fill pump to proper level if needed.

2. Faulty Oil Pressure Sensor

Refer to section 5: Oil Level Low.

3. Dirty Oil Filter or Oil Cooler

Check the operation of oil filter bypass valve. Clean or install a new core for the oil cooler. Drank crankcase and refill with clean lubricant. Install new oil filter elements.

4. Too Much Clearance Between Rocker Arm Shaft and Rocker Arms

Check lubrication in valve compartment. Install new parts as necessary.

5. Oil Pump Suction Screen Is Dirty

Inspect, clean suction screen.

6. Oil Pump Pressure Regulating Valve Does Not Close

Clean valve and housing. Install new parts as necessary.

7. Faulty Oil Pump

Repair or replace oil pump as necessary.

8. Too Much Clearance Between Crankshaft And Crankshaft Bearings

Inspect the bearings and install new crankshaft bearings as necessary.

9. Too Much Clearance Between Camshaft And Camshaft Bearings

Inspect the bearings and install new camshaft bearings as necessary.

10. Broken Piston Cooling Jet

Install new jet and check piston and liner for seizure.

Too Much Oil Consumption, Blue Smoke in the Exhaust

Probable Root Causes:

* Plugged crankcase breather

* Too much lubrication oil in engine sump

* Oil leaks

* Excessive engine operation at idle or low load

* Oil temperature is too high

* Worn valve guides

* Worn, damage, or incorrectly installed piston rings

* Worn pistons or blockage of oil return holes in piston

* Failure of seal rings in turbocharger

* Crankcase ventilation

* Intake oil misters

See Operation & Maintenance Manual SEBU6495 or SEBU6278; Engine Operation for addition information.

Perform the following tests in order:

1. Plugged Crankcase Breather

A dirty crankcase breather will cause high crankcase pressure, which can lead to gasket and seal leakage. Clean breather and lines.

2. Too Much Lubrication Oil In Engine Sump

Remove extra oil. Determine where excess oil comes from. Fill the correct amount of oil in engine sump.

3. Oil Leaks

Check for oil leaks into the intake system. Make repairs as needed.

4. Excessive Engine Operation at Idle or Low Load

Do not idle engine or operate engine at less than 50 percent load for extended periods of time.

5. Oil Temperature Is Too High

Check operation of thermostats. Check operation of oil cooler. Install new parts if necessary. Clean the oil cooler core. Refer to Section 3: Engine Oil Temperature Too High.

6. Worn Valve Guides

Reconditioning of the cylinder head is needed.

7. Worn, Damage, Or Incorrectly Installed Piston Rings, Worn Pistons or Blockage or Oil Return Holes in Piston

Inspect and install new parts if necessary.

8. Failure of Seal Rings in Turbocharger

Check inlet manifold piping for oil and make repairs to the turbocharger if necessary.

9. Crankcase Evacuation

Crankcase evangelization set to high on BioGas Engines.

10. Intake Oil Misters

Intake oil misters set too high. Disable oil mister pump. See Engine News, January 04, 2000; SEBD9284; Oil Mister Pump And Lines Group No Longer Used.

White Smoke in Crankcase Blowby Fumes, Coolant in Lubrication System

Probable Root Causes:

* Jacket water leak into combustion chamber

* Aftercooler core failure

* Failure of the oil cooler cores

* Cracked cylinder block

Perform the following tests in order:

1. Jacket Water Leak into Combustion Chamber

To identify which cylinder has the leak, check the ESS panel for diagnostic codes and exhaust port temperatures.

When engine load is less than 50 percent, use DDT to place engine in Prechamber Calibration Mode. In PC-CAL mode, the 501-02 through 506-02Diagnostic Codes that indicate a 20 percent misfire rate is enabled.

Use the DDT to place the engine in Prechamber Calibration Mode and depress the ALT2button, this converts the displayed actual Burn Time for the individual cylinders from an averaged value to non-averaged value. A misfire has occurred if the displayed time is greater than 14 milliseconds.

Inspect combustion chamber components for evidence of coolant leak and component damage. Check for failed prechamber gasket seal. Thoroughly clean and inspect the prechamber sealing surfaces, install new gaskets. Check for jacket water leak at the prechamber cooling insert in the bottom of the cylinder head. Check for cracked or warped cylinder head.

Show/hide table

NOTICE
If coolant is found in the inlet manifold, major engine damage will occur if the coolant is allowed to remain in the engine. Remove prechambers, suction water from cylinder, replace oil.

2. Aftercooler core failure

Check coolant level in separate circuit expansion tank. Check the ESS panel for diagnostic codes and exhaust port temperature. Misfire occurring on multiple cylinders is an indication of coolant in the inlet air manifold. Remove drain plug from inlet air manifold, check for coolant, at 50 percent load or less (small amounts of oil from the inlet manifold is from the inlet valve lubrication system). Inspect and if necessary, replace failed Aftercooler core.

3. Failure of the Oil Cooler Cores

Install a new core in the fault oil cooler. Drain crankcase and refill with clean lubricate. Install new oil filters.

4. Cranked Cylinder Block

Pressurize the cooling system to locate damage.

Oil In Cooling System

Probable Root Causes:

* Engine Oil Cooler

Perform the following tests in order:

1. Engine Oil Cooler

Inspect each cooler and make a replacement or repair oil cooler.

Engine Oil Temperature Is Too High

Probable Root Causes:

* Faulty oil temperature regulators

* Restriction to flow of oil or water through the oil cooler

Perform the following tests in order:

1. Faulty Oil Temperature Regulators

Check the oil temperature regulators for correct operation. Check temperature gage operation. Repair or replace parts as necessary.

2. Restriction to Flow of Oil or Water Through The Oil Cooler

Clean and flush the oil cooler.

Engine Coolant Temperature Is Too High

Probable Root Causes

* Water pump Cavitation

* Restriction to coolant flow through radiator core

* Radiator Tubes

* Restriction to air flow through radiator or raw water

* Flow through the heat exchanger

* Low fan speed

* Low coolant level in system

* Pressure cap failure

* Combustion gases in coolant venting

* Faulty water temperature regulators (thermostats) or temperature gage

* Faulty jacket water pump

* Too much load on the system

* Coolant and/or flow incorrect

* Scale buildup

Perform the following tests in order:

1. Water Pump Cavitation

Install a ball check valve in the jacket water pump outlet. Start the engine. Open ball check valve in order to check for aerated coolant. Measure system temperatures and pressures at various points to identify possible locations of restricted flow. Measure supply pressure to jacket water pump inlet to ensure sufficient pressure is present to prevent pump Cavitation. Check coolant mixture.

2. Restriction to Coolant Flow through Radiator Core Tubes or Heat Exchanger

Clean and flush radiator or heat exchanger.

3. Restriction to Air Flow through Radiator or Raw Water Flow Through the Heat Exchanger

Remove all restrictions of flow.

4. Low Fan Speed

Check for worn or loose fan belts.

5. Low Coolant Level in System

Add coolant to cooling system.

6. Pressure Cap Failure

Check operation of Pressure cap. Install a new pressure cap if necessary.

7. Combustion Gases In Coolant

Identify cylinder with prechamber gasket joint leak to determine where gases enter the cooling system. Operate engine at low load. Monitor exhaust port temperatures and combustion burn times. Inspect spark plugs for moisture or evidence of coolant deposits. Bore scope prechamber to inspect for moisture entry. Reseal failed gasket joint. Refer to Disassembly and Assembly manual for your engine.

8. Faulty Water Temperature Regulators (Thermostats) Or Temperature Gage

Check water temperature regulators for correct operation. Check temperature gage operation. Install new parts as necessary.

9. Faulty Jacket Water Pump

Repair the jacket water pump as necessary.

10. Too Much Load On the System

Reduce the system load.

11. Scale Buildup

Cleaning cooling system and coolant conditioner level.

12. Coolant and/or flow incorrect

System incorrectly balanced. Repair as needed.

13. High Ambient Temperature

If ambient temperature is above cooling system design temperature reduce load.

14. Engine Coolant Temperature is Too Low

Probable cause is faulty or wrong water temperature regulators installed.

Poor Coolant Flow

Probable Root Causes:

* Restriction of coolant flow through the Aftercooler core

* Faulty Jacket water pump

* Faulty Aftercooler pump

* Coolant and/or flow incorrect

* Scale buildup

Perform the following tests in order:

1. Restriction Of Coolant Flow Through The Aftercooler Core

Clean and flush the Aftercooler cores.

2. Faulty Jacket Water Pump

Repair the jacket water pump as necessary.

3. Faulty Aftercooler Pump

Repair the faulty Aftercooler pump as necessary.

4. Coolant and/or Flow incorrect

System incorrectly balanced. Repair as needed.

5. Scale Buildup

Clean cooling system.

SCM Will Not Reset

Probable Root Causes:

* Electrical Connector

* Faulty Mode Control Switch

* Faulty SCM

Perform the following tests in order:

1. Electrical Connector

Inspect connectors and associated wiring for damage, abrasion, corrosion or incorrect attachment. Refer to Section 5: Inspecting Electrical Connectors for details.

2. Faulty Mode Control Switch

Connect a jumper wire between terminal-12 on the SCM and -Battery. Disconnect the jumper wire. If the LED resets (OFF) when the jumper wire is connected the problem is in the MCS or wiring to the MCS, repair as required.

3. Faulty SCM

If the LED does not reset verify that the fault condition no longer exists. If the fault cannot be reset, replace the SCM

Engine Shutdown with SCM LED Active

Probable Root Causes:

* All Fault LED's are active on the SCM

* Overcrank LED

* Overspeed LED

* Low Oil Pressure LED

* High Oil Temperature LED

* Emergency Stop LED

* Auxiliary LED

NOTE: Before Proceeding with this test procedure verify that the set points are programmed correctly. Improperly programmed set points will cause the SCM fault Indicators to become active. Refer to Section 2: Programming Parameters.

Perform the test for your symptom:

1. All Fault LED's are active on the SCM

Disconnect wires from terminal-8 on the SCM. Measure the voltage between +Battery and -Battery. The voltage should be between 18 and 32 VDC. If the wiring to terminal -8 on the SCM is grounded, correct the problem. If the voltage is 15 VDC or less, battery voltage is low. Charge battery or correct wiring problem as required. If battery voltage is above 15 VDC replace the SCM.

2. Overcrank LED

If the Overcrank LED is ON, reset the SCM by turning the Mode Control switch to the OFF/RESET position. If the Overcrank LED is still on, refer to Section 3: SCM Will Not Reset.

3. Overspeed LED

Turn the Mode Control Switch (MCS) to the OFF/RESETposition. Restart the engine and verify that this eliminates the problem. If the engine Overspeed LED comes ON again, place the MCS to the STARTposition and operate at rated speed. Monitor the gas shutoff valve and magneto ground signal. Press and hold the Verify Switch on the back of the SCM. Release the switch after the engine stops. Check that the gas shutoff valve and magneto ground signal caused the engine to shutdown. Also, check that the overspeed LED, on the SCM, is flashing. Turn the MCS to the OFF/RESETposition. If shutdown speed is 75 percent of overspeed set point, the overspeed function is OK. If the set points have been lost or incorrectly set refer to section 2: Programming Parameters.If the Overspeed fault indicator remains on refer to Section 3: SCM Will Not Reset.

4. Low Oil Pressure LED

Install a reliable oil pressure gage and start the engine. At idle and rated speed, verify that the gage and the SCM, display the same pressure readings. If the oil pressure is low, STOPthe engine and repair the problem in the engine lube system. If the pressure gage and the SCM display are NOT the same check for a poor connection at the wiring and harness connector from the module to the Engine Oil Pressure Sensor. If the problem is not found replace the sensor.If low pressure still exists replace the Oil Pressure Transducer Module.If the low pressure remains, replace the SCM.If the engine oil pressure is below the set points at low or high idle refer to System Operation, Testing And Adjusting Manual.

5. High Oil Temperature LED

Install an accurate oil temperature gage with the sensing bulb in an area of high oil flow, as close to the temperature probe as possible. Start the engine and allow the oil temperature to stabilize.

If the temperature displayed by the gage and the SCM are above the set point, troubleshoot the oil cooling system. Refer to System Operation Testing and Adjust Manual.

If the temperature displayed by the SCM is 50 °C (90°F) or higherthan the temperature displayed by the gage, verify that the gage is accurate. If the SCM continues to read high, replace the sensor. If the high temperature still exists replace the Oil Pressure Transducer Module.If the high temperature remains replace the SCM.

If the temperature displayed on the SCM is HI and the temperature on the gage is below 90°C (194°F) check for short in the wiring to the pressure temperature module. Repair as required.

6. Emergency Stop LED

Reset all emergency stop push buttons by turning counterclockwise (CCW) until it pops out. Turn the MCS to the OFF/RESETposition. Disconnect the wire from terminal-14 on the SCM. If the Emergency Stop LED is OFF when the wire is disconnected, repair as required.Place the MCS to the OFF/RESETposition and back to the STARTposition. If the LED remains ON refer to Section 3: SCM Will Not Reset/

7. Auxiliary LED

Turn MCS to OFF/RESETposition. IF the LED is ON, disconnect wire from terminal-13 on the SCM. If the LED is OFF when the wire is disconnected from terminal-13. Check wiring and/or replace the auxiliary shutdown relay as required.

Improper Load Indication

Probable Root Causes:

* Improper BTU setting

* Pressure line leak to pressure module

* Air/Fuel Pressure Sensor

Perform the following tests in order:

1. Improper BTU setting

Verify the BTU setting is correct for the fuel that is being supplied to the engine.

Obtain a gas analysis and enter information into the Caterpillar Methane program to determine the Lower heating Value of the fuel.

Place in PC CAL and measure the exhaust emissions, compare the data with the readings from the commissioning report. Adjust the BTU setting to obtain 100%.

2. Pressure line leak to pressure module on air or fuel Check for leaks in the pressure lines between the fuel manifold, air manifold and pressure modules.

3. Air/Fuel Pressure Sensor Replace the pressure module.

4. Fuel or Air Pressure Leak

Check for a leak in the air and fuel manifolds. Check for a leak in the air and fuel supply lines to the pressure module.

Coolant Leak Into Combustion Chamber

Probable Root Causes:

* Failed pre-combustion seals

* Damaged pre-combustion seal surfaces

* Damaged or leaking pre-chamber insert

* Cracked cylinder head

NOTE:

Coolant leaks can result in damage to the engine from any of the following: detonation, over heating of the pre-chamber, valve failure, or hydraulic lock.

Coolant leaking into pre-combustion chamber can cause the spark plug not to fire. Sufficient quantities of coolant in the pre-combustion chamber can cause detonation and over heating of the pre-chamber.

Large leaks can cause hydraulic lock of the cylinder, which may result in failed combustion ring or a bent connecting rod.

Perform the following tests in order:

1. Inspect the spark plug and combustion probe for deposits colored similar to the coolant color. If the spark plug has colored deposits the leak is getting into the pre-combustion chamber.

*Disassemble the pre-chamber from the ignition body and inspect sealing surfaces on the pre-chamber, ignition body, and in the cylinder head. Make appropriate repairs.

2. Damaged or leaking pre-chamber insert Use a flexible bore scope through the combustion probe hole to confirm that the insert is leaking. Make appropriate repairs.

3. Cracked cylinder head

Remove cylinder head to determine the source of the leak. Make appropriate repairs.