CTS-V V8-6.0L VIN U (2006)
Fuel Supply Line: Description and Operation
FUEL FEED AND RETURN PIPES
The engine compartment connecting fuel pipe connects the chassis fuel pipe to the fuel rail assembly. The engine compartment fuel pipe is constructed of
Teflon(R) with a braided stainless steel covering.
The chassis fuel pipe is located under the vehicle on the left side of the tunnel. The chassis fuel pipe connects the rear fuel feed pipe from the left fuel
sender assembly to the engine compartment connecting fuel pipe. The chassis fuel pipe is constructed of aluminum with a plastic coating.
The rear fuel feed pipe connects the left fuel sender fuel pipe to the chassis fuel pipe. The rear fuel feed pipe is constructed of nylon with a covering of
heat resistant rubber hose.
The auxiliary fuel feed pipes and the auxiliary fuel return pipes are located inside of the fuel crossover hose and inside of each fuel tank. The fuel pump
supplies fuel through the auxiliary fuel feed pipe to the siphon jet pump inside the right fuel tank. The siphon jet pump transfers fuel from the right fuel
tank to the left fuel tank through the auxiliary fuel return pipe. The return pipe feeds returning fuel from the right fuel tank directly into the left fuel
sender reservoir. The auxiliary fuel feed and return pipes are constructed of nylon.
NYLON FUEL PIPES
CAUTION: In order to reduce the risk of fire and personal injury observe the following items:
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Replace all nylon fuel pipes that are nicked, scratched or damaged during installation, do not attempt to repair the sections of the nylon
fuel pipes
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Do not hammer directly on the fuel harness body clips when installing new fuel pipes. Damage to the nylon pipes may result in a fuel leak.
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Always cover nylon vapor pipes with a wet towel before using a torch near them. Also, never expose the vehicle to temperatures higher
than 115°C (239°F) for more than one hour, or more than 90°C (194°F) for any extended period.
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Apply a few drops of clean engine oil to the male pipe ends before connecting fuel pipe fittings. This will ensure proper reconnection and
prevent a possible fuel leak. (During normal operation, the O-rings located in the female connector will swell and may prevent proper
reconnection if not lubricated.)
Nylon pipes are constructed to withstand maximum fuel system pressure, exposure to fuel additives, and changes in temperature. There are 2 sizes of
nylon fuel pipes used. A 9.53 mm (3/8 in) ID pipe is used for the fuel feed pipe and the auxiliary fuel return pipe. A 7.94 mm (5/16 in) ID pipe is used
for the auxiliary fuel feed pipe. Heat resistant rubber hose protects the section of the rear fuel feed pipe that is exposed to chafing, high temperature or
vibration.
Nylon fuel pipes are somewhat flexible and can be formed around gradual turns under the vehicle. However, if nylon fuel pipes are forced into sharp
bends, the pipes will kink and restrict the fuel flow. Also, once exposed to the fuel, nylon pipes may become stiffer and are more likely to kink if bent too
far. Take special care when working on a vehicle with nylon fuel pipes.
