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Home >> GMC >> 2003 >> Envoy 4WD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Basic Diagnostic Procedures - 4.2L >> Fuel Systems >> Fuel System Pressure Release
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Fuel System Pressure Release

WARNING: Remove fuel tank cap and release fuel system pressure before servicing any fuel injection related components. After releasing fuel system pressure, a small amount of fuel may be released when servicing fuel lines, fuel pump or fuel connections. Cover fuel system components with a shop towel before disconnection. DO NOT allow fuel to contact engine or electrical components.
CAUTION: Fuel system is under pressure. Pressure must be released prior to servicing fuel system.

Remove fuel pump relay from underhood fuse/relay block. Crank engine. Allow engine to start and stall. Crank engine for an additional 3 seconds to ensure release of any remaining fuel pressure. Disconnect negative battery cable in order to avoid re pressurizing fuel system. Reinstall fuel pump relay. Tighten fuel filler cap.

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