When should the MAF calibration table be adjusted, and how do VE, MAF, and PE work together for WOT fueling?

How they fit together:

• MAF: GM computers rely mainly on the mass airflow sensor, which measures the air entering the engine so the computer can pick injector pulse width (HP Academy).
• Speed density (VE): because the MAF lags on sharp throttle openings, GM added a speed-density subsystem. LS computers blend the two, running MAF only, MAF plus speed density, or speed density only, depending on conditions (LSX Magazine). In speed density, the VE table is the key input.
• Power enrichment (PE): at wide-open throttle the target is much richer than stoichiometric, and the narrowband sensors can't measure it, so WOT fueling is set open loop and checked with a wideband. Factory calibrations run WOT a little richer than best power as a safety margin (LSX Magazine).

When to adjust the MAF table: when the MAF is the airflow source and your wideband or trims show the fueling is off — typically after intake, MAF housing or engine airflow changes. Correct injector data has to be in first, or the airflow numbers will be wrong. See tuning fundamentals.

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