Fuel Pump: Description and Operation

The main fuel pump receives its fuel from the priming pump (located inside the fuel tank) and in turn delivers it to the fuel distributor under a pressure of approx. 5.5 bars. The main fuel pump as well as the priming pump operates as soon as the ignition is energized, for about 1 second, to build pressure for starting, then remains energized as long as the engine rotates. The electric current to the pumps is controlled by a relay which is in turn controlled by the electrical impulses supplied by the ignition distributor's pulse generator. Thus, with the engine stopped, the pumps are not energized.