Fuel Pump Discharge Flow Control System - Subaru SVX 1992 Manual

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EMISSION CONTROL SYSTEM AND VACUUM FITTING

10 . Fuel Pump Discharge Flow

Control System

If the fuel pump discharge is always constant, the

injection amount from the jet pump increases at high

engine speeds, and this leads to increased generation

of evaporation gas .

This fuel pump discharge flow control system reduces

the fuel pump discharge and return flow to reduce the

injection quantity from the jet pump, thereby reducing

the generation of evaporation gas at higher engine

Fuel pump modulator

1) At low engine speeds, the source current flows

directly through the fuel pump to the ground, and the

fuel pump sends fuel at the specified discharge rate .

2) As the engine speed increases, the ECU sends a

signal out to the fuel pump modulator to allow the

source current to flow through the fuel pump modulator

and resistor to ground.

3) In this way, the amount of current flowing through

the fuel pump varies with engine speed, thus fuel pump

discharge is controlled .

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