Section 10-01: Fuel Tank, Filter and Electric Fuel Pump
1994 Mustang Workshop Manual
DESCRIPTION AND OPERATION
Fuel Tank and Fuel Tank Filler Pipe
All vehicles are equipped with a restricted fuel filler opening which
functions as follows:
An opening in the fuel tank filler pipe (9034) allows only non-leaded fuel
nozzles to be inserted. The restrictor is a narrow opening in the filler
covered by a spring steel trap door.
The smaller non-leaded fuel nozzle will fit through the narrow opening
and push the trap door aside, allowing normal filling. Leaded fuel nozzles will
not fit through the opening.
A closed trap door causes fuel to back up and the automatic nozzle to
shut off.
The fuel tank filler pipe is manufactured as an assembly and must be
serviced by removing and replacing with a new fuel tank filler pipe. Do not
modify in any way.
Fill limiting is accomplished through fill pipe configuration and/or
internal vent lines within the fuel tank filler pipe and fuel tank (9002)
.
The fill limiting system is designed to permit an air space when the fuel tank
is filled to capacity of approximately 10-12 percent.
This space provides for thermal expansion of fuel and necessary for proper
functioning on the in-tank vapor vent system.