0433512 JOHNSON CYLINDER HEAD, 185

R1S1-UP)PumperSPF343C (S/N: R2A1-UP; RTX1-UP)The Dynamic Gas Blending (DGB) system requires certain engine operating parameters to be met for optimal gas blending.To enable the DGB system for substitution of gas at the highest percentage possible, the following conditions should be met.
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 to 66° C (130° F to 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 to 690 kPa (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 shot off valve (GSOV) will remain closed, no gas blending will occur.
Worn pilot linkage in fuel gas pressure regulator. The 555-2855 Regulator Kit is 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. The following faults that can generate codes:
HI EXHAUST TEMPERATURES: Cylinder exhaust port and turbocharger temperatures are present when temperatures exceed the set value for the programmable monitoring system. Air cleaner service and aftercooler or other repairs may be required to reduce high exhaust temperatures.
KNOCK LEVEL: High knock level is present when the knock sensors are registering a vibration level in the frequency range where knock events occur. This can be a result of low coolant and inlet manifold air temperatures. Loose or worn components on the engine can also result in high knock levels.
High fuel valve actuator 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 supplied to it than could be delivered at the maximum fuel valve position.
2452-9 Generator Total Real Power : Abnormal Update Rate. Correct cause of active DTC – often related to J1939 data link issues. This is a customer supplied signal.
An active 632-5 Engine Fuel Shutoff Valve #1 : Current Below Normal DTC. Install updated 488-2147 Coil to correct this DTC. Reason parameter will show "DTC active".
Install Intake Manifold Air Pressure relocation kit to prevent moisture freezing in line to IMAT sensor. Refer to Engine News, SEBD9909, New Boost Pressure Sensor Location Is Used for Certain 3512 Petroleum Engines for information to relocate Boost/IMAT sensor.
Check Cat® Electronic Technician (ET) for any active or logged codes, repair as required.
Under engine configurations using Cat ET, set the "Engine Driven Accessory Load Configuration" to 101 hp. In certain versions of engine software, the default configuration is too high and will prevent blending with no associated reduction reason code