0332203 JOHNSON SCREW, By-pass cover

6 Potential Reason Codes
No reduction
Diagnostic Trouble Code (DTC) active
Low engine load
High turbocharger inlet temperature
High detonation level
High fuel actuator valve commandNo Reduction
The reason code, NONE (No Reduction), is displayed when the following items are within acceptable limits and operating properly:
Load
Speed
Fuel quality
Fuel supplyFactory testing has determined the maximum allowable substitution for specific speeds and loads with optimum fuel quality. The maximum allowable substitution is to ensure safe engine operation and compliance with the published emissions limits.When this reason code is active, the substitution is at the expected percentage based on the speed and load the engine is running.Diagnostic Trouble Code (DTC) Active
The reason code, DIAG ACTIVE (Diagnostic Trouble Code (DTC) Active), is present when there is an active engine diagnostic code. The active engine diagnostic code has caused the DGB control system to eliminate or reduce substitution.When an active diagnostic code on the engine is present, the focus should be resolving the active code.Low Engine Load
The reason code, LOW LOAD (Low Engine Load), is present when the engine load is less than the required minimum to allow substitution.Probable Causes:
Low load
The engine is being operated below the minimum load range for gas substitution.
For drilling generator packages, the load must be approximately 18% for gas substitution to be enabled.Lost load signal
Verify that the EMCP is generating a load signal.
Verify that the ECM is receiving the load signal through Cat® Electronic Technician (ET).Incorrect load signal
Check the load signal that is being generated on the EMCP with the load calculated by the customer controller.High Turbocharger Inlet Temperature
The reason code, HI TURBO TEMP (High Turbocharger inlet Temperature), is present when turbine inlet temperature exceeds the set value for the programmable monitoring system.Probable Causes:
Individual cylinder temperature reads high
Replace Thermocouples if one is radically off from other
Turbine inlet temperature reads high
Injector leakage
High inlet manifold pressure
High inlet manifold temperature
Turbocharger performance issue
Intake restriction
Exhaust restrictionRefer to Troubleshooting, "Inlet Air Is Restricted".Refer to Troubleshooting, "Exhaust Temperature Is High".High Detonation Level
The reason code, HI DET LEVEL (High Detonation Level), is present when the detonation sensors are registering a vibration level in the frequency range that detonation events occur.Probable Causes:
Gas quality
High inlet manifold pressure
High inlet manifold temperature
Incorrect timing calibration
Faulty circuit for the detonation sensor
Incorrect detonation sensor torque
Intake restriction
Turbocharger damage
Inlet manifold temperature below 30° C (86° F)
Valve lashRefer to the Troubleshooting, "Detonation Occurrence".High Fuel Valve Command
The ECM controls the fuel actuator valve to deliver gaseous fuel to the engine. The reason code, HI VALVE CMD (High Fuel Valve Command), is present when fuel actuator valve reaches 80% open. Essentially the engine needs more gaseous fuel than can deliver at the maximum fuel valve position.Probable Causes:
Low supply pressure
The recommended supply pressure range is 207 kPa to 241 kPa (30 psig to 35 psig)
The acceptable supply pressure range is 83 kPa to 276 kPa (12 psig to 40 psig)The supply pressure can be lowered below the recommended 207 kPa to 241 kPa (30 psig to 35 psig) if the volume is sufficient to allow enough gas flow.Gas quality
Low BTU heat value gaseous fuel
High inert gas levelRefer to Application and Installation Guide, LEBW4977, "Gaseous Fuels".Regulator pressure
Adjust the regulator pressure to 10.3 kPa to 24.1 kPa (1.5 psig to 3.5 psig) supply to the fuel valveIf adjusting the regulator pressure does not work:
Check for GSOV failure.
Check for pressure regulator failure.
Check for upstream restriction of supply gas.Incorrect mixing tubes
There are two different Btu ranges for the mixing tubes. Verify that the correct range is being used on each engine.Fuel line restriction downstream of fuel valve
Check for foreign objects in the fuel line
Check for proper mixing tubesGas supply pressure fluctuations
Inadequate gaseous fuel supply or flow rateNo or Low Gas Substitution
Jacket water (JW) coolant temperature must be at least 88° C (190° F). Low JW temperature can cause cylinder knock which is picked up by the knock sensors. This will reduce or stop fuel gas substitution.Intake Manifold Air Temperature (IMAT), must be above 30° C (86° F) in order for the gas blending system to become active. An IMAT between 54° C and 66° C (130° F and 150° F) is the ideal air inlet manifold temperature for the highest percentage of gas substitution. Tests have proven that once the IMAT drops below 54° C (130° F), the fuel gas substitution will start to reduce. Cold IMAT can also result in unburnt gas even though the unit is showing gas substitution.Natural Gas temperature must be above 10° C (50° F). This minimum temperature is required to prevent freezing of fuel gas components and prevent liquids from dropping out of the fuel gas.Natural Gas pressure must be between 83 kPa minimum to 690 kPa maximum (12 psi to 100 psi). Gas pressure that is too high can damage DGB system components. Gas pressure that is too low will not allow for proper substitution rates.Engine must be operating with a minimum of 20% engine load factor. With an engine load factor under 20% the gas shut off valve (GSOV) will remain closed, no gas blending will occur.Worn pilot linkage in fuel gas pressure regulator. The 555-2855 Regulator Kit (Repair Kit)available for pilot linkage. Worn fuel gas regulator pilot linkage can result in #1 inlet absolute pressure low/high events. Fuel gas pressure diagnostic codes (1390-##) will stop gas substitution. This will result in fuel gas substitution being disabled for 5 minutes. Engine fuel valve absolute pressure low or high event codes will be logged.DGB enable switch circuit status must be enabled. To check this view the DGB enable switch parameter in Cat ET flex fuel status screen and ensure the switch status changes when switch is operated.No active diagnostic trouble codes (DTC) can be present for substitution to take place. When an active diagnostic code on the engine is present the gas substitution rate is 0%. The focus should be on resolving the active code. Faults that can generate codes:
HI EXHAUST TEMP (Cylinder exhaust port and