Precision Turbo and Engine BigStuff3 GEN3 PRO SEFI (LS1) System Hardware & BigComm Software - Manual (Page 73)

BigStuff3 Pro SEFI System (LS1)
Version 1.0 72
The “position” values shown in the table below can be used as a baseline for most applications.
You can see from the large values in the table that when the coolant temperature is cold, the IAC
seeks a position in the direction of the fully open position (position number 180). As the engine
reaches normal operating temperature, the IAC finds the position that allows the engine to idle at
the user prescribed “Desired” idle speed.
While the engine is running, a “real-time Ellipse” will move within the IAC Start Position table
relative to the current engine Coolant Temperature “operating point”. Use it as a point of
reference to help calibrate the IAC Start Position table.
To change a value in the IAC Start Position table, move the cursor using the PC’s mouse or
arrow keys to the cell to be changed. Input the desired value and hit ”Enter” to save the change.
44. IAC Gain Terms
This input table allows the user to set how quickly the IAC motor moves (in or out) in a given
period of time. Use the default settings that come with the ECU unless it becomes necessary to
control the IAC motor speed. The Proportional Gain setting should be from 4 to 16. The
Derivative Gain should be ¼ to ½ of the Proportional Gain. Enter the desired value in the table
and left mouse click OK to save the information.