PLUG-BLEED 3Q7771 - Caterpillar

an engine is first installed, the following steps must be completed for the initial setup of the Air/Fuel Ratio Control (AFRC).
Ensure that the engine controller is set to the correct engine configuration. Refer to Systems Operation, "Reset to Start". Selecting the improper configuration will cause bad engine response.
Open the power valve in order to eliminate any restriction in fuel flow. Turn the valve counterclockwise by three to four turns.
Position the control valve to the START position of 350 steps for the G3412 and G3516 engines. Position the control valve to the START position of 800 steps for the G3408 engine. Ensure that the switch is in the manual mode.
Bring the engine up to rated speed and load. Do not exceed the rated load. While the AFRC is still in the START position, adjust the power valve. Turn the valve in the clockwise direction in order to adjust the emissions level to 1 g/bhp of NOx.
After tuning the engine, verify proper operation of the NOx sensor by comparing the displayed reading to the reading on the portable measurement instrument. The slope and offset calibration adjustments are available. These adjustments are not normally required for the G3408 and G3412 engines.
Switch the air/fuel ratio control to the automatic mode in order to activate the control.
Operate the engine at various load and speed combinations in order to ensure that the air/fuel ratio control maintains the proper NOx emission levels. If necessary, adjust the offsets to the NOx target for the various inlet manifold pressures and speeds which represent the partial load points on the engine.