AEM 30-6905 Universal Programmable EMS-4 - Manual (Page 156)

Page 156 of 279 EMS-4 Install and Tuning Guide_Rev 1.6
The RPM Offset vs TPS table or “Throttle Follower” table is used to keep the idle control
system from fighting the driver command during very light throttle applications like creeping in
traffic. Sometimes very light throttle application by the driver will not make the TPS % exceed
the value set for the Idle Off if TP Over option. When this happens the ECU will try to close the
IAC valve to keep the idle speed at the target. This can cause a sluggish feel to the engine.
This table can be used to add additional air bypass as the throttle is opened slightly to account
for this condition.
The Ign vs Idle RPM table can be used to allow ignition timing to help control idle. If the actual
engine speed is below the target, this table can add timing. If the actual engine speed is above
the idle target, this table can subtract timing. Some OEM ECU‟s use this method and refer to it
as “Idle Spark Scatter” because the ignition timing will fluctuate rapidly up and down as the ECU
uses it to help control idle speed.
Idle Channels
Idle Target Units: RPM, Description: This is the final idle target RPM that the IAC motor is
attempting to achieve after all idle compensators.
Idle Target Error Units: RPM, Description: RPM value above or below the Idle RPM Target
value.
Idle Base Units: %, Description: Percent of idle control motor position generated from the Idle%
vs Target table.
Idle Position Units: Idle %, Description: Final compensated idle air bypass percentage.
Idle Learned Value Units: Idle %, Description: The idle percentage above or below the target
idle. Zero percent would represent no correction to the IAC motor to achieve the target idle.