This is the most fundamental question. "PT" is an acronym that describes the pump’s unique operating principle. It stands for "Pressure-Time."

• Pressure: The pump generates fuel pressure (in PSI). This pressure is supplied to the injectors.

• Time: The injectors are open for a specific amount of time (measured in milliseconds), which is controlled by the engine's camshaft.

The amount of fuel injected is therefore determined by the Pressure of the fuel supplied to the injector and the Time the injector inlet port remains open. It’s a simple yet brilliantly mechanical way to meter fuel, making the system self-compensating for engine speed without the need for complex electronic controls.

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