PLATE 2G1244 - Caterpillar

Starting Position of the Fuel Valve
The starting position for the fuel valve is the default position when automatic control is activated. The preferred position is slightly higher than the middle range of the fuel valve's travel (approximately 900 to 1000 steps). This enables the control to maximize the amount of adjusting of the lean and rich mixtures of the air and fuel.For the reset process, the fuel valve's motor is retracted. The control retracts the motor by attempting to open the fuel valve beyond the motor's mechanical stop. In the fully retracted position, the fuel valve is fully open. The fully retracted position corresponds to zero steps. The control keeps track of the fuel valve's position.After zero steps are achieved, the control commands the motor to move the fuel valve for the number of steps that are programmed for the starting position. The default starting position is 1000 steps. The control keeps track of the number of steps that are moved. This enables the control to calculate the position of the fuel valve during operation. When the air/fuel mixture is richened, the control subtracts the corresponding number of steps. When the air/fuel mixture is leaned, the control adds the corresponding number of steps.After the starting position is achieved, the oxygen buffer is powered up in order to preheat the oxygen sensor for start-up.Resetting the motor's position prior to engine start-up is recommended. This ensures that the starting position for automatic control is obtained and the control can determine the actual position of the fuel valve during operation.When the control is powered down, the last position of the fuel valve is recorded in non-volatile memory. Unless the fuel valve is reset to