Warning: These are advanced tables and only should be altered by experienced tuners. Leaning out the target lambda will result in increased exhaust gas temperatures and increased NOx emissions.
These tables control the target lambda (air/fuel ratio) under closed loop. The target lambda may be monitored from the AFCMD sensor.
Three tables are used to determine the target lambda - two tables at different load points (Target Lambda ECT Low and Target Lambda ECT High), and a final limit table (Target Lambda Limit).
The target lambda is calculated by reading the Target Lambda ECT Low and High values, and then interpolating between the values by engine load (MAP) with loads points at approximately 32 kPa for the low table and 82 kPa for the high table. The lower (richer) of the this interpolated value and the Target Lambda Limit are used for the target lambda.
To lean out closed loop operation first increase (lean out) the limit table, then increase the target lambda.
The above highlighted changes will result in a normal target lambda while warming up; leaner (15.5:1 or 1.05 λ) at light load (~ 32 kPa), changing to stoichiometric (14.7 or 1.0 λ) at high load (~82 kPa).
Leaning the lambda out past stoichiometric will give higher cylinder and exhaust gas temperatures, which may damage the engine / catalytic converter / exhaust system. It is not recommend to run leaner than stoichiometric when using a catalytic converter as nitrogen oxide emissions increase sharply.