IAC-AUTO Adjustment Procedure:
The IAC-AUTO function is a rapid altering feature of the ThunderMax Base Map. The
ThunderMax is constantly learning and adjusting the IAC Stops as you operate the
motorcycle. The purpose of the IAC-AUTO function is to rapidly alter the general shape
and position of the IAC vs. Engine Temperature map page.
1.) Link to the module, prepare your engine monitor gauges and turn on the
Monitoring function, as described in the Linking to the ThunderMax ECM and
Engine Monitor Values & Gauges sections.
2.) Select the IAC Stops vs. Engine Temperature tuning map page.
3.) Start the engine, paying close attention to the monitor gauges.
a. Use all proper safety precautions when starting the engine.
b. Make certain the transmission is in Neutral.
c. Make certain the cable linking the ECM to the computer is not touching any
part of the exhaust system.
4.) If the engine idle appears to be stable after 15-20 seconds, select the “IACAUTO”
button and allow SmartLink to rapidly alter the IAC Stops during the initial
warm-up. The “IAC-AUTO” button will react like the “Link” and “Monitor” buttons,
it will turn green when it is active, and red when it is inactive.
5.) Allow the engine head temperature to reach a maximum of 289o F by letting it sit
at idle, turn off the “IAC-AUTO” function and shut off the motorcycle. The engine
should not be turned off during this operation until cylinder head temperature
reaches 289° unless an unusual occurrence that could result in engine damage
is present (such as engine RPM racing).
a. DO NOT walk away from the motorcycle while it is running at idle. Serious
damage can occur if the head temperature goes beyond 325o F and is
allowed to continue upwards without supervision.
b. The IAC Stops will now be 5 points below the IAC Position; you must display
the IAC Position monitor gauge if you desire to view spread during the
correction process. This process should be done throughout the entire
temperature range up to 289 degrees. The engine will not return to the correct
idle speed properly if the IAC Stops are not set correctly.
c. If the IAC Stop is too low, the idle speed can drop too far below the intended
idle speed. This could cause the engine speed to approach a stall when the
throttle is closed or pop thru the intake when the throttle is quickly twisted.
6.) Turn the ignition back to the “ON” position, without restarting the engine. This will
re-establish the link between SmartLink and the ThunderMax ECM. Previously it
was recommended to “Align” the remaining tuning blocks that were not adjusted
by the IAC-Auto function. This is no longer necessary for ThunderMax ECM’s
with a Firmware version 4.0 or higher. The ThunderMax ECM now employs a
constant learning feature which will continue to learn and adapt to the changing
conditions of the engine, as well as changing ambient conditions.
IAC Curve Problem Solving:
IAC Position Value is too low or the IAC-AUTO adjustment is making large
changes to the base map curve: The system hasn’t been properly initialized.
Reinitialize the module by cycling the power on & off, this establishes the proper
position for the IAC motor. Restart the engine and start the process again. See page 11
for the complete ThunderMax ECM Initialization procedure.
Rough Idle, Engine Does Not Start, or Does Not Stay Running:
The wrong map may be selected for the application, or the AFR is so far off that the
engine will not stay running. If you are operating in Open Loop (no Auto-Tune), Double
check the definitions of the map that you are using, then install a probe in the tail pipe to
determine the AFR.
Excessively High Idle:
If the ECM has previously been mounted on another motorcycle, or older firmware has
recently been updated, the IAC stops will have learned offsets that need to be cleared.
To clear the offsets, select Map Editing > Clear “Learned Idle Control Adjustments
