Pontiac FIREBIRD 1972 Service Manual page 1124

8-4 1972 PONTIAC SERVICE MANUAL
NOTE: F SERIES USES
UU T
UNDERBODY
~ n c c
I
REINF. (REF.)
UNDERBnn"
SADDLE
\ n c r . l
I
VlEW A
(FRONT STRAP MOUNT)
VlEW C
(REAR STRAP MOUNT)
A 1-118" LONG
SPACER O N
REAR STRAP
BOLTS.
GAGE
FUEL
TANK
(REF.)
VlEW B
Fig. 8-4 Installation of Fuel Tank (Except Station Wagon)
rately. The filter is designed not to rattle on the bottom of
the tank.
Because of the difference in construction and location of
the fuel tanks, different fuel tank gage units are required
for standard and station wagon models. All A, G and F
Series V-8 engine cars with 4-barrel carburetors and B
Series with air conditioning use a fuel tank gage unit
which has an additional pipe attached to it for fuel vapor
return from the fuel pump to the tank.
The fuel gage tank unit consists of a float with linkage
connecting the float to a variable resistor. As the float
raises or lowers according to the fuel level, the resistor
varies the resistance for electrical current to flow through
the tank unit and the amount of current flowing through
the dash unit (see Sedtion 12 for operation of the dash
unit). When the fuel tank is empty, the float is positioned
so the resistor has almost zero resistance. This causes the
dash unit to register empty. As the fuel level increases, the
float moves up and the resistance in the resistor increases
to approximately 90 ohms. This causes the indicator on
the dash unit to move toward the full mark.
FUEL PIPES, HOSES AND CLAMPS
The ECS vapor pipe is routed with the brake pipe along
the left side frame rail of all B, F and X Series. On A Series
with V-8 engines and all G Series the fuel pipe and brake
pipe are routed alongside each other on the left side frame
rail. There are no fuel system pipes routed on the left side
frame rail of A Series models with 6-cylinder engines.
A fuel pipe and fuel vapor return pipe are routed on the
right side frame rail of all B Series and F Series. The ECS
vapor pipe and fuel vapor return pipe are routed on the
right side frame rail of A Series with V-8 engines and all