If IP=Fuel metering, then HF injectors?

[AndyL]

If the Injection pump does the fuel metering what are the high flow injectors for?

[Kennedy]

Fuel metering goes by the ASSUMPTION that a pulse or solenoid closure time of "x" gives a delivery of "y" based on a new stock injector. Like most any injection system, an injector with a higher delivery rate will deliver percentage more fuel and will then skew this calculation...