AEM 30-71XX Infinity Stand-Alone Programmable Engine Mangement System Full Manual - Manual (Page 137)

Tuning Guide 131
© 2014 AEM Performance Electronics
Lambda Control Tuning
When an O2 sensor is connected directly to the Infinity ECU, the ECU can use closed-loop
feedback to react to changes in the engine's fuel delivery requirements, or to compensate for
sections of the VETable that could still benefit from additional tuning. When Lambda feedback is
active, the ECU compares the desired LambdaTarget value against the measured Lambda1
value from the O2 sensor and then adjusts the fuel trim for each injector in an attempt to bring the
measured value closer to the target value.
O2 Sensor Assignment:
Before enabling closed-loop lambda feedback, use the Injector Setup page in the wizard to
assign each fuel injector's feedback to use the Lambda1 or Lambda2 sensor. For most simple
4-cylinder engines, all four injectors will be assigned to use the same O2 sensor for feedback. A
more complex example would be a GM LS1 engine with two O2 sensors; each sensor should be
installed in the exhaust collector for each bank of cylinders. The left bank of cylinders (1,3,5,7)
should be assigned to one Lambda sensor and the right bank of cylinders (2,4,6,8) should be
assigned to the other Lambda sensor. This allows the ECU to trim each bank of injectors
independently based on each of the two Lambda sensors. Before enabling feedback using
multiple O2 sensors, test that the Lambda1 / Lambda2 sensor assignment is correct for each
injector by adjusting the values in the injector fuel trim tables (Inj1FuelTrimTable [%]) and
confirming that the appropriate sensor indicates a change in measured AFR.
Lambda Target Trims:
Aside from the main LambdaTargetTable, there are a few other functions that can alter the target
lambda value:
LambdaAfterStartTrim:
LambdaAfterStartTrim is a 2D table that allows the ECU to target a richer mixture for some
time after the engine is started, or when the engine is cold. See the
Engine Start section
for more details.
LambdaTrimN2O:
LambdaTrimN2O is calculated by the ECU's Nitrous control function, to modify the target
lambda value when nitrous is active. See
Nitrous N2O for more details.
LambdaTrim_Knock is calculated by the ECU's Knock Control function, to modify the
target lambda value in response to knock sensor activity. See
Knock Control for more
details.
In addition to these lambda trims, the ECU can switch between multiple Lambda Target
maps. See
Multi-Map Features for more details.
Lambda Feedback Activation:
Use the wizard to configure the conditions that allow Lambda feedback to be activated. See
Lambda Control for details.
Please also note that there are some conditions that will cause Lambda Feedback to be
89
117
205
195
256
198