PIPE ASSEM. 8H8246 - Caterpillar

Tmax - Maximum ambient temperature for the month in deg FTcurrent - Current ambient temperature in deg FTest Procedure - Fuel Correction Factor (FCF)
Start the engine
Monitor the FCF value using Cat ET
The FCF should be at 100 percent 5 percent above 50 percent load.
If, the FCF value is out of range, refer to "Adjustment Procedure - Fuel Correction Factor."Test Procedure - Calibrate NOx Sensor
Start the engine
Apply minimum load to the engine
Ensure that the engine operating conditions have stabilized.
Access the Service tab using ET
Access the Calibrations tab using ET
Access the Engine Exhaust NOx Level Sensor screen using ET.
Follow the prompts given in ET to guide you through the calibration procedure.
Compare the NOx value displayed in ET with the emissions analyzer value.If, the values are not consistent refer to the adjustment procedure.Test Procedure - Fuel Analysis
Obtain Current Fuel Analysis
Use the methane number to determine desired timing.
Low Heat Value (LHV) is used for engine setup (configuration)
Specific Gravity (SG) is used for engine setup (configuration)
Specific Heat Ratio (SHR) (K) is used for engine setup (configuration)
With the system powered up and before starting the engine, use Cat ET to disable the NOx feedback system.Disabling the NOx feedback system will put the engine in open loop mode so the air/fuel ratio can be adjusted manually.
Start the engine
Allow the engine to warm up, then load the engine.
Verify that the engine NOx sensor is warmed up and operating.
Allow the emission analyzer NOx reading to stabilize.
If the engine speed is unstable, refer to the Testing and Adjustingprocedure for Adjusting the Governor Gain Setting.Test Procedure - Fuel Pressure
Check the fuel supply pressure to the gas pressure regulator. Fuel supply pressure to the gas pressure regulator should be within 220 to 242 kPa (32 to 35 psi).
Check the engine gas pressure to the fuel metering valve. If, the pressure is not 17.2 to 20.7 kPa (2.5 to 3.0 psi) refer to Adjustment Procedure - Gas Pressure to Fuel Metering Valve.Adjustment Procedure - Gas Pressure to Fuel Metering Valve
Illustration 30 g03046277
(1) Bolt
(2) Cover
Remove cap (2)
Adjust bolt (1) to achieve desired fuel pressure to the fuel metering valve.
After desired pressure is reached, install cap (2).Adjustment Procedure - NOx Sensor Calibration
Adjust the NOx value using Cat ET to match the emission analyzer value.Note: Make small changes to the slope during calibration. If, large changes are made the engine may become unstable. Allow the engine to stabilize after each adjustment.Adjustment Procedure - Engine Speed
Select Engine Speed Parameters in the Configuration tab using Cat ET
Set the governor control to Isochronous
Set the Minimum High Idle to 925 rpm.
Set the Maximum High Idle to 1400 rpm.
Set the Governor Gain (Proportional) to 100.
Set the Governor Stability (Integral) to 100.Adjustment Procedure - Desired Timing
Select Desired Timing in the Configuration Tab using Cat ET.
Set the timing based on the methane number.
Select the Configuration screen
Input LHV, SG, SHR (K), and desired NOx into the appropriate blanks.Adjustment Procedure - Fuel Correction Factor (FCF)
The Fuel Correction Factor should be 100 percent +/- 5 percent. When factor is not 100 percent, adjust the