The key to the FAST EZ-EFI system is its adaptive learning feature. This system goes beyond normal closed loop fuel control. In essence, it tunes itself by using oxygen sensor feedback to adjust the underlying base fuel table as well as the instantaneous fueling. This way the closed loop system only has to make fine adjustments. We found that the system took a while to learn, and the more we ran the engine, the better it did. If installed in a car, the best tactic would be to get the engine idling good and then drive around for an hour or so.