Chrysler Concorde 1993, Руководство по обслуживанию, Страница: 500 / 820

INSTALLATION
(1) Install the rubber grommet in the fuel pump
module.
(2) Lubricate the grommet with a light coating of
Power Steering Fluid. Push the valve downward
into the grommet. Twist valve until the ports are
properly positioned (Fig. 17).
(3) Install fuel pump module. Refer to Fuel Pump
Module Installation in this section.
FUEL PRESSURE REGULATOR
The fuel system uses a vacuum balanced, non-
adjustable fuel pressure regulator. The powertrain
control module (PCM) does not operate the regulator.
On 3.3L engines, the pressure regulator sits in the fuel
rail (Fig. 18). On 3.5L engines the regulator attaches to
the fuel return tube at the rear of the engine below the
intake manifold plenum (Fig. 19).
On 3.3L engines, the regulator maintains fuel system
pressure at approximately 317 kPa (46 psi) with mani-
fold vacuum applied to it and the engine idling.
Without vacuum applied, the 3.3L regulator maintains
pressure at approximately 379 kPa (55 psi).
On 3.5L engines, the regulator maintains fuel system
pressure at approximately 317 kPa (39 psi) with mani-
fold vacuum applied to it and the engine idling. With-
out vacuum applied, the 3.5L regulator maintains
pressure at approximately 379 kPa (48 psi).
A leaking vacuum supply hose can change fuel sys-
tem pressure. To determine if the regulator operates
correctly, check fuel system without vacuum applied to
the regulator.
The pressure regulator contains a diaphragm, cali-
brated spring and a fuel return valve (Fig. 20). The
spring pushes down on the diaphragm and closes off
the fuel return port. Manifold vacuum applied to the
top of the diaphragm acts against the spring pressure
while fuel pressure pushes on the bottom of the dia-
phragm. The combination of fuel pressure and intake
manifold open the return port. The more intake mani-
fold vacuum applied to the regulator, the less fuel
pressure required to open the return port. System fuel
pressure reflects the amount of fuel pressure required
to open the return port. System pressure varies with
different amounts of intake manifold vacuum.
With low vacuum, such as during wide open throttle
conditions, minimal vacuum assistance is available
and full spring pressure is exerted to seal the fuel
outlet causing. This causes system pressure to in-
crease. With high vacuum, such as during idle, fuel
pressure on the bottom of the diaphragm is balanced by
intake manifold pressure on the spring side. This
results in lower system fuel pressure.
For fuel pressure regulator service, refer to the
Service Procedures section in this group.
Fig. 19 Fuel Pressure Regulator—3.5L Engine Fig. 17 Pressure Relief/Rollover Valve
Fig. 18 Fuel Pressure Regulator—3.3L Engine
FUEL SYSTEMS 14 - 7