Fuel Delivery
An electric fuel pump (located inside fuel tank as an integral part of fuel gauge sending unit) supplies fuel under pressure to throttle body. The ECM actuates fuel pump through fuel pump relay located in relay panel when ignition is turned on or to start position. If engine stalls or is not cranked within 1 second after ignition is turned on, ECM will deactivate fuel pump.
The fuel pressure regulator is an integral part of throttle body. A diaphragm-operated relief valve regulates fuel pressure. `Relief valve is exposed to atmospheric pressure on bottom side and top side senses fuel pressure to maintain constant 10.5 psi pressure across fuel injectors. Fuel in excess of that used to maintain pressure is returned to fuel tank through fuel return line.
During normal running, 2 fuel injectors are actuated alternately by the ECM and they direct metered atomized fuel into the throttle bores above the throttle valves. Both injectors are actuated simultaneously during cranking.