This fuel pump delivers diesel from the tank to the high-pressure injection system at the required flow rate and pressure. It mounts on the engine block or chassis rail and is driven by the engine’s timing gear or an electric motor, depending on the specific installation. A worn or failing pump reduces fuel delivery, causing hard starting, low power, and erratic engine operation under load. The manufacturer machines the pump body and internal components to the same tolerances as the original assembly, so no adapter plates or shims are needed for installation. Replace the inlet and outlet seals when installing the new pump.