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Home >> GMC >> 1990 >> Forward Control 6.2 J, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Basic Testing >> Chart A-6, Fuel System Pressure Test >> Engine Controls - Basic Testing >> Circuit Description
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Circuit Description

When the fuel pump is running, fuel is delivered to the injector(s) and then to the regulator where the system pressure is controlled to about 9-13 psi. Excess fuel is then returned to the fuel tank.

NOTE: Numbers below refer to circled numbers on diagnostic chart.