Volumetric Efficiency (VE) is a comparison of the real world volume of air/fuel mixture drawn in and the actual volume of the cylinder if it were completely filled. "Pumping Efficiency" is another synonym. Typical figures for naturally aspirated engines is roughly 80%. Turbocharged and supercharged motors almost always have a VE greater than 100%.

Fuel tables present in Honda ECUs are (in a slightly roundaboout way) volumetric efficiency tables. The VE value is stored as the result VE multiplied by the theoretical maximum airflow corrected for the size of the injector to give a desired Air Fuel Ratio, i.e. Injector Size x VE x Theoretical Pumping Possibility (assumed temperature and atmospheric pressure for Ideal Gas Law conditions) This is merely a shortcut to save the ECU from having to do all the ideal gas law calculations and then multiply by VE to get airflow, and then multiply again by a factor to account for injector size. Intake Air Temperature Sensor correction is then used to adjust the fueling to match the actual intake air temp rather than the one assumed in the creation of the VE table.