: In modern systems, an Electronic Control Unit (ECU) uses signals to trigger high-pressure solenoid valves , replacing the mechanical rack and governor for more precise control.
: When you press the accelerator, a control rack rotates the plunger. This changes the position of the helix, determining how long the spill port stays covered and, consequently, how much fuel is delivered to the cylinder. Common Pump Types in Animations
: Driven by the engine's camshaft, the plunger moves upward. Once it covers the barrel ports, the trapped fuel begins to compress.