Chrysler New Yorker. Manual — part 257

FUEL DELIVERY SYSTEM

DESCRIPTION AND OPERATION

FUEL DELIVERY SYSTEM

The front wheel drive car uses a plastic fuel tank

located rear center of the vehicle.

The Fuel Delivery System consists of: the electric

fuel pump module, fuel filter, tubes/lines/hoses, fuel
rail, and fuel injectors.

The in-tank fuel pump module contains the fuel

pump. The pump is serviced as part of the fuel pump
module. Refer to Fuel Pump Module.

The fuel filter is replaceable, it is a combination

fuel pressure regulator/filter on the fuel pump mod-
ule. Refer to the Maintenance Schedules in the Intro-
duction section of this manual for recommended fuel
filter replacement intervals.

FUEL PUMP MODULE—ALL

The fuel pump module contains the fuel pump, fuel

reservoir, level sensor, inlet strainer, and fuel pres-
sure regulator/filter (Fig. 1). The inlet strainer, level
sensor and fuel pressure regulator/filter are the only
serviceable items. If the fuel pump requires service,
replace the fuel pump module.

ELECTRIC FUEL PUMP

The fuel system uses a positive displacement, gero-

tor gear, immersible pump with a permanent magnet
electric motor. The pump draws fuel through a
strainer and pushes it through the motor to the out-
let. Check Valve Operation: The pump outlet contains
a one-way check valve to prevent fuel flow back into
the tank and to maintain fuel supply line pressure
(engine warm) when pump is not operational. It is
also used to keep the fuel supply line full of gasoline
when pump is not operational. After the vehicle has
cooled down, fuel pressure may drop to 0 psi (cold
fluid contracts), but liquid gasoline will remain in
fuel supply line between the check valve and fuel
injectors. The fuel pump relay provides voltage to
operate the fuel pump.

FUEL LEVEL SENSOR

This procedure tests the resistance of the level sen-

sor itself. It does not test the level sensor circuit.
Refer to Group 8W - Wiring Diagrams for circuit
identification.

The level sensor is a variable resistor. Its resis-

tance changes with the amount of fuel in the tank.
The float arm attached to the sensor moves as the
fuel level changes.

FUEL TANK

The fuel tanks of all Chrysler Motors built vehicles

are equipped with fuel and vapor controls that allow
the vehicle to pass a full 360° rollover without fuel
leakage.

Front Wheel Drive fuel delivery systems contain a

fuel tank rollover valve. The valve is mounted on top
of the fuel tank. The valve functions as a tank pres-
sure control valve while the vehicle is upright, but
contains a check valve that prevents fuel from escap-
ing from the fuel tank when the vehicle is turned
over.

The fuel filler cap acts as a pressure/vacuum relief

valve. When air pressure inside the fuel tank gets too
high or too low, the fuel filler cap opens to relieve the
difference in pressure.

Fig. 1 Fuel Pump Module—Typical

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FUEL SYSTEM

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An evaporation control system restricts fuel evapo-

ration into the atmosphere and reduces unburned
hydrocarbons. Vapors from the fuel tank are collected
in a charcoal filled canister. The vapors are held in
the canister until the engine is operating. When the
engine is running, the vapors are drawn through the
intake manifold into the combustion chambers.

FUEL INJECTORS

The fuel injectors are 12 ohm electrical solenoids

(Fig. 2). The injector contains a pintle that closes off
an orifice at the nozzle end. When electric current is
supplied to the injector, the armature and needle
move a short distance against a spring, allowing fuel
to flow out the orifice. Because the fuel is under high
pressure, a fine spray is developed in the shape of 2
streams. The spraying action atomizes the fuel, add-
ing it to the air entering the combustion chamber.
The injectors are positioned in the cylinder heads.
Fuel

injectors

are

not

interchangeable

between

engines.

The injectors are positioned in the cylinder heads

with the nozzle ends directly above the intake valve
port (Fig. 3).

FUEL FILTER/FUEL PRESSURE REGULATOR

A combination fuel filter and fuel pressure regula-

tor is used on all gas powered engines. It is located
on the top of the fuel pump module. A separate frame
mounted fuel filter is not used.

Fuel Pressure Regulator Operation: The pres-

sure regulator is a mechanical device that is cali-
brated to maintain fuel system operating pressure of
approximately 338 kPa (49 psi) at the fuel injectors.

It contains a diaphragm, calibrated springs and a

fuel return valve. The internal fuel filter (Fig. 4) is
also part of the assembly.

Fuel is supplied to the filter/regulator by the elec-

tric fuel pump through an opening tube at the bot-
tom of filter/regulator.

The fuel pump module contains a check valve to

maintain some fuel pressure when the engine is not
operating. This will help to start the engine.

If fuel pressure at the pressure regulator exceeds

approximately 49 psi, an internal diaphragm closes
and excess fuel pressure is routed back into the tank
through the pressure regulator. A separate fuel
return line is not used with any gas powered engine.

Fig. 2 Fuel Injector

Fig. 3 Fuel Injector Location—Typical

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FUEL SYSTEM

300M

DESCRIPTION AND OPERATION (Continued)

PRESSURE-VACUUM FILLER CAP

The fuel filler cap incorporates a two-way relief

valve that is closed to atmosphere during normal
operating conditions. The relief valve is calibrated to
open when a pressure of 10 kPa (1.5 psi) or vacuum
of 6 kPa (1.8 in. Hg) occurs in the fuel tank. When
the pressure or vacuum is relieved, the valve returns
to the normally closed position.

CAUTION:

Remove the fuel filler cap to release

fuel tank pressure before disconnecting any fuel
system component.

QUICK-CONNECT FITTINGS

Different types of quick-connect fittings are used to

attach various fuel system components. These are: a
single-tab type, a two-tab type or a plastic retainer
ring type. Some are equipped with safety latch clips.
Refer to the Removal/Installation section for more
information.

CAUTION:

The interior components (o-rings, spac-

ers) of quick-connect fitting are not serviced sepa-
rately. Do not attempt to repair damaged fittings or
fuel lines/tubes. If repair is necessary, replace the
complete fuel tube assembly.

Fuel tubes connect fuel system components with

plastic quick-connect fuel fittings. The fitting con-
tains non-serviceable O-ring seals (Fig. 5).

CAUTION:

Quick-connect fittings are not serviced

separately. Do not attempt to repair damaged quick-
connect fittings or fuel tubes. Replace the complete
fuel tube/quick-connect fitting assembly.

The quick-connect fitting consists of the O-rings,

retainer and casing (Fig. 5). When the fuel tube
enters the fitting, the retainer locks the shoulder of
the nipple in place and the O-rings seal the tube.

ROLLOVER VALVE

The LH fuel tank has fuel and vapor controls that

allow the vehicle to pass a full 360° rollover without
fuel leakage. Refer to Group 25, Emission Controls
System for information.

Fig. 4 Side View—Filter/Regulator

Fig. 5 Plastic Quick-Connect Fittings

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FUEL SYSTEM

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DESCRIPTION AND OPERATION (Continued)

DIAGNOSIS AND TESTING

FUEL LEVEL SENSOR

This procedure tests the resistance of the level sen-

sor itself. It does not test the level sensor circuit.
Refer to Group 8W - Wiring Diagrams for circuit
identification.

The level sensor is a variable resistor. Its resis-

tance changes with the amount of fuel in the tank.
The float arm attached to the sensor moves as the
fuel level changes. To test the level sensor, connect
an ohmmeter across the sensor signal and sensor
ground terminals of the fuel pump module connector
(Fig. 6). Move the float lever to the positions shown
in the resistance chart (Fig. 6). Record the resistance
at each point. Replace the level sensor if the resis-
tance is not within specifications.

FUEL INJECTORS

For fuel injector diagnosis, refer to the Fuel Injec-

tor Diagnosis charts.

Fig. 6 Level Sensor Diagnosis

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FUEL SYSTEM

300M