Mitsubishi 1993 3000GT, Technical Information Manual

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Power supply control to the injector, air flow sensor, ISC
servo, etc. is the same as in the conventional 6G72
engine. Fuel pump control for controlling power supply to the
fuel pump is also the same as in the conventional 6G72
engine.
FUEL PUMP DISCHARGE
VOLUME CONTROL
Fuel pump discharge volume is controlled in two steps
according to the amount of intake air (engine load) in 1
cylinder in 1 cycle for improved reliability of the fuel
pump. When the amount of intake air in this 1 cylinder 1
cycle is small (engine load is low), the engine control
unit turns on the power transistor so current flows in the
coil of fuel pump relay No.2. As a result, the relay switch
changes form A to B (refer to the figure on the left.), and
current flows via the resistor to the fuel pump motor. The
supply voltage to the fuel pump is reduced since the
voltage is lowered by the resistor, pump speed falls and
the amount of fuel discharged from the fuel pump is
reduced.
When the amount of intake air in this 1 cylinder 1 cycle
is large (engine load is high), the engine control unit
turns off the power transistor and changes the relay
switch from B to A (refer to the figure on the left.). As a
result, voltage drop due to the resistor increases, pump
speed rises and the amount of fuel discharged from the
fuel pump increases.
ENGINE - Control System
POWER SUPPLY AND FUEL PUMP CONTROL