Fuel priming pulse

The priming pulse essentially "primes" the intake before the car starts by spraying a pulse of fuel into it. This wets the intake walls which helps atomization by vaporizing the fuel from the turbulence caused when the intake valve is opened, sucking tbe pulse into the engine. For cars with long intake runners and injectors far from the valves, this is more important to tune so there is no delay in fuelling when cranking is initiated. For cars like Miatas with injectors spraying almost directly onto the back of the intake valves, this setting isn't strictly necessary to tune.