5.3 Fuel System
Thread Starter
Teching In
Joined: Jan 2025
Posts: 3
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5.3 Fuel System I have an 04 Silverado 1500 with a 5.3 flex fuel in it. It’s got an aftermarket intake manifold so I can’t check the fuel pressure. The engine has upgrades internally with a bigger cam than stock. Every once in awhile I’ll get a lean code then it’ll go away. All injectors are new and upgrades from stock. I’m planning on putting a new fuel pump in but not sure if I need a regulator or not. Im using the stock fuel system which doesn’t have a return line and didn’t have a regulator in the first place.
I’ve read on another forum that the 04 5.3 stock fuel system has a pressure regulator back at the tank. I plan on just swapping the pump itself and keeping the original assembly will this work?
I’ve read on another forum that the 04 5.3 stock fuel system has a pressure regulator back at the tank. I plan on just swapping the pump itself and keeping the original assembly will this work?
TECH Regular
Joined: Dec 2022
Posts: 444
Likes: 158
An 04 does have a regulator in the pump assembly
From manual:
Fuel System Description (Pick-up and Utility)Fuel System OverviewThe Fuel System is a returnless on-demand design. The fuel pressure regulator is a part of the fuel sender assembly, eliminating the need for a return pipe from the engine. A returnless fuel system reduces the internal temperature of the fuel tank by not returning hot fuel from the engine to the fuel tank. Reducing the internal temperature of the fuel tank results in lower evaporative emissions. An electric turbine style fuel pump attaches to the fuel sender assembly inside the fuel tank. The fuel pump supplies high pressure fuel through the fuel filter and the fuel feed pipe to the fuel injection system. The fuel pump provides fuel at a higher rate of flow than is needed by the fuel injection system. The fuel pump also supplies fuel to a venturi pump located on the bottom of the fuel sender assembly. The function of the venturi pump is to fill the fuel sender assembly reservoir. The fuel pressure regulator, a part of the fuel sender assembly, maintains the correct fuel pressure to the fuel injection system. The fuel pump and sender assembly contains a reverse flow check valve. The check valve and the fuel pressure regulator maintain fuel pressure in the fuel feed pipe and the fuel rail in order to prevent long cranking times
From manual:
Fuel System Description (Pick-up and Utility)Fuel System OverviewThe Fuel System is a returnless on-demand design. The fuel pressure regulator is a part of the fuel sender assembly, eliminating the need for a return pipe from the engine. A returnless fuel system reduces the internal temperature of the fuel tank by not returning hot fuel from the engine to the fuel tank. Reducing the internal temperature of the fuel tank results in lower evaporative emissions. An electric turbine style fuel pump attaches to the fuel sender assembly inside the fuel tank. The fuel pump supplies high pressure fuel through the fuel filter and the fuel feed pipe to the fuel injection system. The fuel pump provides fuel at a higher rate of flow than is needed by the fuel injection system. The fuel pump also supplies fuel to a venturi pump located on the bottom of the fuel sender assembly. The function of the venturi pump is to fill the fuel sender assembly reservoir. The fuel pressure regulator, a part of the fuel sender assembly, maintains the correct fuel pressure to the fuel injection system. The fuel pump and sender assembly contains a reverse flow check valve. The check valve and the fuel pressure regulator maintain fuel pressure in the fuel feed pipe and the fuel rail in order to prevent long cranking times
