The high-pressure discharge fittings on the head of the injection pump connect to the injection nozzles with steel lines of equal length and interior volume (figure 4-6). The ends of the injection lines have special fittings and nuts.
When the engine is not running, fuel is contained in the injection lines. During operation, a residual pressure of approximately 500 psi is maintained in each injection line. As injection occurs in each line, a small amount of fuel enters the line. This creates a pressure wave that pushes a similar amount of fuel into the nozzle at the other end of the line.