Fuel System
Fuel under pressure from electric fuel pump, flows through a pulsation damper (some models) to a pressure regulator. The pressure regulator consists of a sealed, spring loaded diaphragm with a connection for intake manifold vacuum. Fuel pressure differential is maintained at approximately 36 psi (2.5 kg/cm2 ) between fuel pressure and intake manifold vacuum to ensure amount of fuel injected is solely dependent upon injector "open" time. Fuel in excess of fuel differential is returned to the fuel tank. To aid in cold engine starting, a cold start valve (injector) is activated by a thermo-time switch (except Datsun 200SX) to increase quantity of fuel to combustion chambers.