G 3500 1 Ton Van V8-454 7.4L (1989)
![background image](/gmc/g_3500_1_ton_van/v8-454_7.4l/Page-824006.png)
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If the vehicle is equipped with a fuel module, the module must be disconnected before performing the fuel system pressure test. Refer to
SECTION 4 of the Fuel and Emissions Manual.
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Fuel system is under pressure. To avoid fuel spillage, refer to procedures in SECTION 4 for testing or making repairs requiring disassembly of
fuel lines or fittings.
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On V6 or V8 engines, the fuel pressure drops to almost zero psi after pump shuts "OFF".