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51 FUEL SYSTEM & EXHAUST
INSTALLATION
Install in reverse order of removal. Make sure
the flange gasket, mounting stud insulator bush-
ings and washers are installed properly.
FUEL LEVER INDICATOR
The fuel level indicator is of the constant
voltage type. It consists of a voltage regulator,
panel indicator and a tank level unit connected by
a single wire system between the units. Figure 15.
FIGURE 15
VOLTAGE REGULATOR
Its function is to regulate the variable (input)
voltage available from the car storage battery, or
the charging system, to produce a constant 5.0
volt output to the gauges. This regulator is a
simple device, operating with a heater bimetal in
conjunction with a pair of contacts.
FUEL LEVEL GAUGE
With the tank empty, the float holds the slide
rheostat (variable resistance) at maximum resis-
tance causing the gauge to read empty.
With the tank full, the slide rheostat is moved
to the minimum resistance point causing the
gauge to read "Full" with the ignition switch on.
The use of the bimetal in the fuel indicator pro-
vides stability of reading and eliminates pointer
fluctuation incidental to
surging in the tank and the float bobbing on
the surface of the fuel.
GAUGE TROUBLE DIAGNOSIS
GAUGE TESTING EQUIPMENT
One new OK tank level unit (constant voltage
type), one new OK panel fuel indicator gauge and
three ten-foot lengths of No. 16 insulated wire
equipped with clip terminals at each end of wire.
VOLTAGE REGULATOR
The constant voltage regulator is common to
both fuel and temperature system, that is, one
regulator is used to operate both systems
.
METHOD OF CHECKING
1. If both gauges read considerably too high- for
example, if the gas gauge reads up the scale
with an empty gas tank and the temperature
gauge reads up scale with a cold engine, the
constant voltage regulator is not working prop-
erly and should be replaced: (Check ground
connections of the voltage regulator as ground-
ing is essential to the proper functioning of the
regulator).
2. If both gauges read too low, either the input
voltage to the C.V. regulator is below 5.0 volts
or the voltage regulator is inoperative and
should be replaced. Check battery voltage out-
put before replacing regulator.
PANEL INDICATOR CHECK
1. Disconnect lead wire at gas tank gauge unit.
2. Hook in a new tank unit.• Ground tank unit.
Place float in empty position. Turn on ignition
switch. Panel gauge should read at (E) on dial.
3. Move float to full position, panel gauge should
read full (F).
NOTE: If check 2 and 3 are OK, both panel
gauge and lead wire are OK. If checks 2 and 3
are not OK, hook up a new tank unit to proper
terminal of panel gauge and eliminate the lead
wire from the panel indicator to the unit from
the regulator circuit. Repeat empty and full
check. If now operating OK, correct or replace
bad wire between tank unit and panel gauge.
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