In calculation of MAF (g/sec), Does the ECU subtract local atmospheric pressure (baro sensor reading) from Manifold Absolute Pressure (MAP sensor reading) to determine the actual air mass entering the manifold at high throttle angle?
Here you are some data gathered from OBDII scanner :
MAP 120 kPa
Baro 99 kPa
So, does the ECU calculate the air mass by (120 kpa) or by (120 - 99 "21 kPa" )?
So MAF =
(RPM /120) x (MAP - Baro) / IAT + 273 x VE x ED x 28.966 / 8.314772
(RPM /120) x (MAP) / IAT + 273 x VE x ED x 28.966 / 8.314772