Tuning AFM Flow

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To calibration the AFM, you need to start with stock injectors, stock AFM flow values and stock WOT compensation values.


1.Warm the car to normal operating temperature, and make a datalog of 5-10 minutes of varied driving.
2.In FlashProManager, open the XY Graph (from Advanced Graphs), and select 'AFM.v' for the X-Axis and 'S.TRIM' for the Y-Axis. Check 'Show mean', check 'Closed loop' and uncheck 'Open loop'. What you now have is a graph of the AFM reading vs how much the ECU has to trim to fuel.
3.Edit the AFM Flow table to apply the differences from the above graph. This is part when some tuning judgment comes in. What you need to do is identify trends in the graph, and alter the AFM voltage to flow calibration. eg if the ECU needs to trim 2-3% fuel from 1.7V to 2.8V, then increase the flow numbers on the AFM Flow tables by 2.5% from 1.72 to 2.81V. Make only 2-3 changes to the AFM Flow table at a time.
4.Save, upload and re-test until the fuel trims are within 1%.



AFM Flow vs fuel trim.  In this case the AFM is reading approx 15% low, and the first tuning change would be to increase the AFM flow numbers by 15%, across the whole table, and then re-test.