AEM 30-6905 Universal Programmable EMS-4 - Manual (Page 153)

Page 153 of 279 EMS-4 Install and Tuning Guide_Rev 1.6
100 Hz = 10,000 uS
300 Hz = 3333 uS
Idle FB Max, Units: Idle %, Description: Maximum air bypass percentage allowed to maintain
the target idle. A typical value is 15%. Before tuning the idle option, this value may need to be
large in order to stabilize idle for normal tuning. After tuning idle, it is a good idea to narrow the
feedback range to eliminate unwanted idle changes.
Idle FB Min, Units: Idle %, Description: Minimum air bypass percentage allowed to maintain the
target idle. A typical value is -5%. Before tuning the idle option, this value may need to be a
large negative number in order to stabilize idle for normal tuning. After tuning idle, it is a good
idea to narrow the feedback range to eliminate unwanted idle changes.
Idle FB Dead Band-, Units: RPM, Description: Disables idle correction below the target idle
speed. A typical value is - 25. This function is very useful if exact idle speeds are not crucial, but
reasonable stable speeds are. If this value is too large, stalling may occur due to low idle
speeds.
Idle FB Dead Band+, Units: RPM, Description: Disables idle correction above the target idle
speed. A typical value is 50. This function is very useful if exact idle speeds are not crucial, but
reasonable stable speeds are. If this value is too large, high idling may occur due to open loop
feedback.
Idle FB Rate, Units: mS, Description: Idle air control feedback time base. Time allowed for an
idle air control motor to respond and make decisions for idle feedback. This function determines
how often the engine RPM is referenced for closed loop feedback in order to make adjustments
and maintain the Idle Target. Decreasing this number speeds decision making but may cause
the idle control to "hunt". Increase this number to the largest value that can still accurately
control the idle. If the idle motor responds slowly to RPM variations off the Idle Target, then
decrease this number. If hunting or surging occurs, increase this number. A typical value is
200mS.
Idle On If TP Less, Units: Throttle %, Description: Throttle dependent idle feedback. Idle
feedback is active when throttle percentage is below this number. This number should be the
same or smaller than the Idle Off If TP Over option. A typical value is 3. In order for idle
feedback to be active, make sure this value is larger than your Throttle parameter during an idle
state.
Idle Off If TP Over, Units: Throttle %, Description: Exit of throttle dependent idle feedback. Idle
feedback is disabled when the throttle percentage is above this number. This value also
determines the reinstatement of idle feedback. This number should be the same or larger than
the Idle On If TP Less option.
Idle PW Output, Drop Down List, Use to select the desired PWM idle control output pin. For
EMS-4 applications, only GPIO 5
– 8 can be used for duty cycle control. See pinout sheet or
schematic for more information.