The Air Pressure input

I'm not too sure what the air pressure sensor is, but as far as MyECU is concerned, it has three wires. One connects to ground, one connects to 5 volts and the other gives a voltage that is connected directly to one of the microcontrollers analog input channels.

The air pressure is sampled continuously and used to do a fine tuning of the amount of fuel that is delivered to the engine. As the air pressure increases, its density increases, necessitating a richer mixture.