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Home >> GMC >> 2003 >> Jimmy 2D Utility, Part Time, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Basic Diagnostic Procedures - 4.3L >> Fuel Systems >> Fuel System Pressure Test >> System Description
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System Description

The control module enables fuel pump relay when ignition switch is turned on. The control module will disable fuel pump relay within 2 seconds unless control module detects ignition reference pulses. The control module continues to enable fuel pump relay as long as ignition reference pulses are detected. The control module disables fuel pump relay within 2 seconds if ignition reference pulses cease to be detected and ignition remains on.

The fuel tank stores fuel supply. The fuel pump supplies fuel through an in line fuel filter to fuel injection system. The pump provides fuel at a higher rate of flow than is needed by fuel injection system. The fuel pressure regulator maintains correct fuel pressure to fuel injection system. A separate pipe returns unused fuel to fuel tank.