Regal V6-191 3.1L (1991)
Fuel Supply Line: Service and Repair
For fuel and vapor line routing, see COMPONENT LOCATION.
WARNING: Always keep a dry chemical (Class B) type fire extinguisher near the work area. A small amount of fuel may be released when
servicing fuel lines or connections. In order to reduce the chance of fire or personal injury, cover the fuel lines or fittings with a shop towel
before disconnecting, to catch any fuel that may leak out. Place the towel in an approved container when the disconnect is complete. Relieve
the fuel system pressure before attempting any repairs. See MAINTENANCE PROCEDURES/FUEL SYSTEM PRESSURE RELIEF.
When replacing fuel feed and return pipes, always replace them with original equipment or parts that meet GM specifications for those parts. The
replacement pipe must have the same type fittings as the original pipes to ensure the integrity of the connection.
NOTE: Do not use copper or aluminum tubing to replace steel tubing. Only tubing meeting the 124M specification or its equivalent is capable of
meeting all pressure and vibration characteristics necessary to ensure the durability standard required.
Many of the feed and return pipes use screw couplings with O-rings. Any time these fittings are loosened to service or to replace components, ensure
that:
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A back-up wrench is used to loosen and tighten fittings.
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Check all O-rings at these locations (if applicable) for cuts or any damage and replace as necessary.
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Use correct torque when tightening these fittings.
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Inspect all pipes for kinks, leaks or dents.
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Pipes must be properly secured to the frame to prevent chafing. A minimum of 6 mm (1/4 inch) clearance must be maintained around a pipe to
prevent contact or chafing.
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Fuel feed and return pipes are secured to the underbody with clamps and screw assemblies.
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Follow the same routing as the original pipe.
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Fuel pipes must not contact the fuel tank or underbody at any point.
FUEL AND VAPOR PIPE REPAIR:
When it is impractical to replace an entire fuel line to repair localized damage, use the following procedure:
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When rubber hose is used to replace pipe, use only reinforced fuel-resistant hose which is identified with the word "Fluoroelastomer" on the hose.
The inside diameter of the hose must match the outside pipe diameter.
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Do not use rubber hose within 100 mm (4 inches) of any part of the exhaust system, or within 254 mm (10 inches) of the catalytic converter.
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In repairable areas, cut a piece of hose 100 mm (4 inches) longer than the portion of line removed. If more than a 6 inch length of pipe is
removed, use a combination of steel pipe and hose so that hose lengths will not be more than 254 mm (10 inches).
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Follow the same routing as the original pipe.
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Cut the ends of the pipe, remaining on the car, square with a tubing cutter. Using the first step of a double flaring tool, form a bead on the end of
each pipe section. If the pipe is too corroded to withstand the beading operation without damage, the pipe should be replaced. If a new section of
pipe is used, form a bead on both ends of it also.
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Use a screw type hose clamp NO. #2494772, or equivalent. Slide the clamps onto the pipe and push hoses 51 mm (2 inches) onto each portion of
the fuel pipe. Tighten the clamps on each side of the repair.
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Pipes must be properly secured to the frame to prevent chafing.
WARNING: Do not attempt to repair flexible fuel lines due to possible fire and personal injury hazard. Replace only with the same type of
flexible fuel lines and fittings as those removed.
NYLON FUEL LINES:
Use the following guide lines while servicing vehicles with nylon fuel lines.
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The use of nylon fuel lines eliminates the knocking noise that sometimes accompanies engine warm-up when metal lines are used. Quick connect
fittings, designed to snap onto nylon lines, eliminates the need for screw couplings, O-rings, and torque specifications when replacing fuel lines.
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Nylon lines are soft and flexible prior to installation in a vehicle. When filled with gasoline for 72 hours, the lines catalyze and harden. Kinks in
nylon lines do not affect driveability.
QUICK CONNECT FITTINGS:
Joining steel pipes to nylon fuel lines is accomplished through the use of quick connect fittings. These fittings snap onto pipes/lines without the use of
tools. Two different styles are used to secure the lines: One utilizes four metal tabs inside the fitting and one has an internal cylinder.
FUEL LINE SEPARATOR
To disconnect fuel lines, tool J 37008 fuel line separator or equivalent, is inserted into the quick connect fitting. Use of this tool reduces fuel spray when
disconnecting the nylon lines if system pressure isn't fully released before service. J37088 is a set of two fuel line separators. J 37088-1, size 5/16 inch,
and J 37088-2, size 3/8 inch.