Fuel Pressure Regulator; Description; Operation; Fuel Pump Description - Chrysler 2004 Concorde Service Manual

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FUEL DELIVERY

FUEL LINES (Continued)
cracked, scuffed, or swelled hoses. Replace hoses that
rub against other vehicle components or show sign of
wear.
Fuel injected vehicles use specially constructed
hoses. When replacing hoses, only use hoses marked
EFM/EFI.
When installing hoses, ensure that they are routed
away from contact with other vehicle components
that could rub against them and cause failure. Avoid
contact with clamps or other components that cause
abrasions or scuffing. Ensure that rubber hoses are
properly routed and avoid heat sources.
The hose clamps have rolled edges to prevent the
clamp from cutting into the hose. Only use clamps
that are original equipment or equivalent. Other
types of clamps may cut into the hoses and cause
high pressure fuel leaks. Tighten hose clamps to 1
N·m (9 in. lbs.) torque.
Inspect all hose connections such as clamps, cou-
plings and fittings to make sure they are secure and
leaks are not present. The component should be
replaced immediately if there is any evidence of deg-
radation that could result in failure.
Never attempt to repair a plastic fuel line/tube.
Replace as necessary.
Avoid contact of any fuel tubes/hoses with other
vehicle components that could cause abrasions or
scuffing. Be sure that the plastic fuel lines/tubes are
properly routed to prevent pinching and to avoid heat
sources.

FUEL PRESSURE REGULATOR

DESCRIPTION

A combination fuel filter and fuel pressure regula-
tor is used on all gas powered engines. It is located
on the side of the fuel pump module (Fig. 8) in the
fuel tank.
It contains a diaphragm, calibrated springs and a
fuel return valve.

OPERATION

Fuel Pressure Regulator Operation: The pres-
sure regulator is a mechanical device that is cali-
brated to maintain fuel system operating pressure of
approximately 400 kPa (58 psi) at the fuel injectors.
Fuel is supplied to the regulator by the electric fuel
pump through an opening tube at the bottom of reg-
ulator.
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 (Fig. 8).
If fuel pressure at the pressure regulator exceeds
approximately 58 psi, an internal diaphragm closes
and excess fuel pressure is routed back into the tank
Fig. 8 PRESSURE REGULATOR
through the pressure regulator. A separate fuel
return line is not used with any gas powered engine.
FUEL PUMP
DESCRIPTION
The electric fuel pump is located in and is part of
the fuel pump module. It is a positive displacement,
gerotor type, immersible pump with a permanent
magnet electric motor. The fuel pump module is sus-
pended in fuel in the fuel tank.
OPERATION
The pump draws fuel through a strainer and
pushes it through the motor to the outlet. The pump
contains a check valve. The valve, in the pump out-
let, maintains pump pressure during engine off con-
ditions, for a short while. It is normal for fuel
pressure to drop to zero after cooldown. The fuel
pump relay provides voltage to the fuel pump. The
fuel pump has a maximum deadheaded pressure out-
put of approximately 880 kPa (130 psi). The regula-
tor adjusts fuel system pressure to approximately
400 kpa ±34 kpa (58 psi ± 5 psi).
NOTE: Checkvalve maintains volume of fuel in the
rail and lines, not pressure.
LH