Riviera V6-231 3.8L VIN L SFI (1991)
Fuel Supply Line: Description and Operation
FUEL TANK
The fuel tank is located under the rear of the vehicle and is the fuel reservoir. The tank has a vertical baffle installed to support the filler tube and to
serve as a slosh baffle. The fuel pump and fuel level sending unit assembly are mounted in the fuel tank as one assembly. The fuel tank assembly also
consists of the fuel filler neck and filler cap.
FUEL FILLER NECK
To help prevent refueling with leaded fuel, the fuel filler neck has a built-in restrictor and deflector. The opening of the restrictor will accept only the
smaller unleaded gasoline nozzle which must be fully inserted to bypass the deflector. Attempted refueling with a leaded fuel nozzle will result in fuel
splashing back out of the filler neck.
FUEL TANK FILLER CAP
The fuel tank filler neck is equipped with a screw type cap. The threaded part of the cap requires several turns counterclockwise to remove. The long
threaded area was designed to allow any remaining fuel tank pressure to escape during the cap removal operation. A ratchet type torque limiting device
prevents over-tightening. To install, turn the cap clockwise until a clicking noise is heard. This signals that the correct torque has been reached and the
cap is fully seated.
NOTE: If a fuel filler cap requires replacement, only a cap with the same features should be used. Failure to use the correct cap can result in a serious
malfunction of the system.
FUEL AND VAPOR PIPES
The fuel feed and return pipes extend from the fuel pump/gauge sending unit to the engine compartment. The pipes are secured to the underbody with
clip and screw assemblies. Both fuel feed pipes and return pipe must be properly routed and retained, and should be inspected occasionally for leaks,
kinks, or dents. If evidence of dirt is found in the fuel rail/injector assembly or fuel filter during disassembly, the pipes should be disconnected and
blown out. Check the fuel strainer on the fuel pump/fuel gauge assembly for damage or omission.
The vapor pipe extends from the fuel pump/gauge assembly to the canister. However, it does not follow the same route as the fuel feed pipe.
Due to the fact that the fuel pipes/hoses are under high pressure on fuel injected systems these systems require special consideration for service.
FUEL LINE "O" RINGS
The fuel line "O" rings used are made of Viton. They are brown in color. Viton is less affected than rubber by the additives used in many fuels.
Therefore, rubber should not be used.
NYLON FUEL LINES
Nylon fuel lines are designed to perform the same function as the steel or rubber fuel lines they replace. Nylon lines are constructed to withstand
maximum fuel pressure, exposure to fuel additives, and changes in temperature.
The fuel feed, return, and vapor lines are assembled as a harness. Retaining clips hold the lines together and provide a means for attaching the lines to
the vehicle. Quick connect type fittings are used at the ends of the fuel feed/return lines and at the in-line filter.
Nylon fuel lines are somewhat flexible and can be formed around gradual turns under the vehicle. However, if forced into sharp bends, nylon lines will
kink and restrict fuel flow. Also, once exposed to fuel, nylon lines may be stiffer and are more likely to kink if bent too far. Some care should be taken
when working on a vehicle with nylon fuel lines:
WARNING: To reduce the risk of fire and personal injury when working on nylon fuel lines:
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Always cover nylon fuel lines with a wet towel before using a torch near it. Also, never expose the vehicle to temperatures higher than
239°F for more than one hour, or more than 194°F for any extended time.
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Take care not to nick or scratch the nylon fuel lines. If damaged, they must be replaced.
