MAF scaling

The MAF scaling tab corrects the MAF Sensor Scaling curve of the loaded ROM from a datalog of your own driving.

What you need

• The ROM you are tuning loaded, with a definition that has a MAF Sensor Scaling table.
• A datalog containing MAF voltage, engine speed, coolant temperature, A/F Correction #1, A/F Learning #1 and the front A/F sensor. The logger definition must list them (Settings › Files › Logger definition file).
• Driving that is steady, at many different airflows.

Steps

1. Press Start logging under Log what this tab needs. This logs exactly the values the tab uses, without changing what is ticked in the Datalogging panel. Drive steady at different loads, then stop.
2. Pick the datalog under Datalog: a recorded session, or a CSV file from your log folder.
3. Look at the result: the curve in the ROM against the corrected one, the correction per point and the samples behind it.
4. Propose corrected curve queues the change as a proposal to review and apply on the Calibration page.

How the correction is worked out

• Closed loop samples give the factor from the fuel trims: (1 + A/F Correction) × (1 + A/F Learning).
• Open loop samples give it from the front A/F sensor against the target AFR: a logged column, else the ROM's open loop fuel table if it holds an air/fuel ratio, else a constant.
• Samples are filtered on coolant temperature, engine speed, steady airflow, fuel cut and the closed or open loop status. Without a status column, a zero A/F Correction means open loop.
• Samples are spread over the curve's voltage points. Points with too few samples keep their value, gaps between measured points are filled, the change per point is limited, and the corrected curve is kept rising.