Precision Turbo and Engine BigStuff3 GEN3 PRO SEFI System Hardware & BigComm Software - Manual (Page 80)

BigStuff3 Pro SEFI System
Version 2.1 – February 2011 73
39. Idle
The “Idle” drop down offers the user five tables to calibrate the engine idle quality. Each input table
will be described in the paragraphs below. To get to the Idle drop down screen, go to the main Tool
Bar and left click on Idle and the screen below will appear. Hold the left mouse down and drag it to the
desired input screen and release the mouse button.
40. Throttle Follower
Throttle bodies used with electronic fuel injection systems have an air by-pass channel molded or
machined into the valve body to allow air to be bypassed around the throttle blades when they are fully
closed. The air entering the engine through the bypass channel is used to control the engine idle speed.
The amount of air needed to maintain a desired engine speed varies depending on engine coolant
temperature, camshaft overlap, etc. The Idle Airspeed Control (IAC) motor (and plunger) control the
amount of air allowed to be bypassed around the throttle blades.
The “Throttle Follower” table allows the user to set a relationship between throttle blade angle and the
position of the IAC metering valve (plunger). This is required to keep the engine from stalling when
the throttle position changes from some percent (%) open to fully closed very quickly.
The fixed values along the bottom of the table below represent the percent (%) throttle position which
increase in increments of eight (8) percent. The input values above the fixed numbers are used by the
ECU to position the IAC metering valve (plunger), inside the bypass channel. The position of the
metering valve (plunger) will vary depending on throttle position. The default values, configured with
the system as shipped, will work with a majority of engine applications.
While the engine is running, a “real-time Ellipse” will move within the Throttle Follower
Table relative to the current TPS (%) “operating point”. Use it as a point of reference to help calibrate
the Throttle Follower table.
To change a value in the Throttle Follower 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.