Active Fuel Tuning parameters
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Active fuel tuning is where the ECU adjusts the fuel tables in real time as you drive. It does this within the ECU, so that an external laptop is not required. Fuel changes are automatically applied to the fuel tables, and can also be downloaded from the ECU.
The ECU uses target lambda tables and the wideband oxygen sensor lambda to alters values in a fuel table adjustment table. The process is continuous and repetitive so that over time the fuel tables become tuned to the actual engine needs.
Active fuel tuning
Enables active fuel tuning.
These options control when active tuning is operational, and what target lambda is used.
Closed loop - active fuel tuning is operational in closed loop.
Open loop - active fuel tuning is operational in open loop.
Use fuel trims - when in closed loop uses the current fuel trims to better determine the underlying fuel table values.
Target Lambda - selects what lambda the active tuning process should target. In closed loop it is best to use same target as the ECU calculated target lambda (AFMCD). In open loop even though the ECU calculates a target lambda, it is possible to use a target lambda table to give finer control over the lambda target.
These settings control how active tuning works.
Delay after engine start - in order to allow the oxygen sensor to warm up and after start fuelling to finish, an after start time delay is used so that active fuel timing is disabled after the engine has been started.
Delay after injector re-start - the oxygen sensor will not recorded lambda accurately for a small amount of time after the injectors re-start, which can be set here. The time delay is used when the injectors have shut down due to overrun, but also from the TPS being out of range or the cam angle being out of range under conditions.
Change per tuning cycle - adjustment of the active fuel table value to the calculated value per tuning cycle. Default = 2%. A larger value will adjust the fuel tables more rapidly but could result in rougher fuel table adjustment values.
Delay in lambda reading - adjusts for the delay between the actual engine lambda and the wideband oxygen sensor reading. 150-250ms is typical. You can measure this by noting how long after the injectors re-start the lambda moves from full lean values.
Maximum change - the maximum active fuel tuning table adjustment value from the original fuel table.
Active fuel smoothing - this specifies the maximum change in the adjustment table delta from the values above and below the active cell (in the same column). This is to prevent the adjustment table from becoming jagged.
Maximum deltas (cam angle, load, rpm) - active tuning determines the closest fuel table cell from the actual cam angle, load and rpm. These settings control how far the actual cam angle, load and rpm values are from the fuel table cell index cam angle, load and rpm values. If the cell is too far from the actual cam angle, load and rpm then no active tuning update will be performed.
These conditions determine when active tuning is active.
Minimum and maximum values - active tuning is only operational when the engine conditions are between both the minimum and maximum values.
Using Active Fuel Tuning