Beretta V6-191 3.1L (1990)
Fuel Supply Line: Description and Operation
FUEL TANK
The fuel tank is used to store fuel for the vehicle. The tank is molded from high density polyethylene, and is located in front of the rear wheels. It is held
in place by two metal straps attached to the underbody. The tank shape includes a sump to maintain a constant supply of fuel around the fuel pump filter
during low fuel conditions and aggressive vehicle maneuvers.
When working on the fuel tank, be sure to observe the important information molded on the bottom of the fuel tank.
FUEL FILLER NECK
To prevent refueling with leaded fuel, the fuel filler neck has a built in restrictor and deflector.
FUEL FILLER CAP
The fuel tank filler neck is equipped with a threaded type cap. The threaded part of the cap requires several turns counter clockwise to remove. A built
in 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 needs replacement, use only a cap with the same features. Failure to use the correct cap can result is serious malfunction of
the system.
FUEL FEED AND RETURN LINES AND PIPES
The fuel feed and return pipes and lines carry fuel from the fuel tank to the fuel rail and back to the tank. For vehicles equipped with the 2.3L or 3.1L
engine, an accumulator is attached to the engine fuel feed pipe to absorb pulsations generated by the injectors cycling.
NYLON FUEL LINES
Nylon fuel lines are designed to perform the same job as steel or rubber fuel lines they replace. Nylon lines are constructed to withstand maximum fuel
system pressure, exposure to additives and changes in temperature. There are two sizes used: 3/8 inch ID for the fuel feed, and 5/16 inch ID for the fuel
return.
Sections of the line that are exposed to chafing, high temperature or vibration are protected with heat resistant rubber hose and/or corrugated plastic
conduit.
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 the fuel flow. Also, once exposed to fuel, nylon lines may become stiffer and more likely to kink if bent to far. Special care should be
taken when working on a vehicle with nylon fuel lines.
WARNING: To reduce the risk of fire and personal injury:
^ Always cover a nylon fuel lines 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.
^ Take care not to nick or scratch the nylon fuel lines. If damaged, they must be replaced.
QUICK-CONNECT FITTINGS
Quick-connect type fittings provide a simplified means of installing or connecting fuel system components. Depending on the vehicle model, there are
two types of quick connect fittings, each used at different locations in the fuel system. Each type consists of a unique female socket and a compatible
male connector. O-rings located inside the female socket, provide the fuel seal. Integral locking tabs or fingers hold the fittings together.
FUEL VAPOR PIPE, LINE AND HOSES
The fuel vapor line is made up of a nylon line and rubber connecting hoses, steel pipe, and a rubber connecting hose. The vapor pipe, line and hoses
carry fuel vapors from the fuel tank to the charcoal cannister.
