Dodge Nitro. Manual — part 676

Fig. 81: Fuel Pressure Solenoid Operation
Courtesy of CHRYSLER LLC

High pressure which is present in the fuel rail flows to the ball seat (1) of the pressure solenoid. The specified
pressure required by the system is built up in the rail by the fuel pressure solenoid building up a magnetic force
which corresponds to this specific pressure by means of a control current from the Electronic Control Module
(ECM). This magnetic force equals a certain outlet cross section at the ball seat of the valve. The rail pressure is
altered as a result of the quantity of fuel which flows off. The current fuel pressure is signaled by the fuel rail
pressure sensor to the engine control module (ECM). The controlled fuel flows back along the return fuel line,
into the tank.

In a de-energized state, the fuel pressure solenoid is closed as the spring force (2) presses the ball into the ball
seat. When driving, the fuel pressure solenoid is constantly open. When engine is started, the fuel pressure
solenoid is held closed by magnetic force. When driving, the pressure of the fluid counteracts the magnetic
force of the coil and the slight spring force.

REMOVAL

FUEL PRESSURE SOLENOID

Review the high pressure fuel system warning before beginning repair. See WARNING.

1 - BALL SEAT
2 - SPRING FORCE
3 - MAGNETIC FORCE
4 - COIL
5 - FUEL PRESSURE SOLENOID
6 - HIGH PRESSURE SUPPLY

2007 Dodge Nitro R/T

2007 ENGINE Fuel System - Nitro

Fig. 82: Exploded View Of Fuel Rail - 2.8L Diesel
Courtesy of CHRYSLER LLC

1. Disconnect negative battery cable.

2. Clean the area around the fuel pressure solenoid with Mopar® Throttle Body Cleaner P/N 04897156AA

or equivalent degreasing solvent and compressed air.

3. Disconnect the fuel pressure solenoid harness connector.

WARNING:

High pressure fuel spray can cause severe cuts, and is extremely
flammable. Before opening any part of the high pressure fuel system, wait
for a minimum of 30 seconds after turning off the engine to allow
pressure to bleed down from the high pressure side of the fuel system.
Otherwise severe personal injury can result when the high pressure fuel
system is opened.

WARNING:

No sparks, open flames or smoking. Risk of poisoning from inhaling and
swallowing fuel. Risk of injury to eyes and skin from contact with fuel.
Pour fuels only into suitable and appropriately marked containers. Wear
protective clothing.

NOTE:

Do allow cleaning solvent or debris to enter the fuel pressure solenoid
harness connector.

2007 Dodge Nitro R/T

2007 ENGINE Fuel System - Nitro

4. Remove fuel rail. See REMOVAL.

5. Clamp fuel rail (2) securely in vise with protective jaws.

6. Counterhold the fuel rail and unscrew the fuel pressure solenoid (3).

7. Use a clean plug to close off the fuel rail pressure solenoid opening if the fuel pressure solenoid will not

be immediately re-installed.

INSTALLATION

FUEL PRESSURE SOLENOID

Review the high pressure fuel system warning before beginning repair. See WARNING.

WARNING:

When working with parts on the high side of the fuel injection
system such as the fuel rail and high pressure injector lines, slowly
loosen the part to allow any residual pressure to bleed down from
the high pressure side of the system.

CAUTION: Once removed, the solenoid must always be replaced. Do not re-use

a fuel pressure solenoid that has been installed in the fuel rail.

NOTE:

Do not allow dirt or debris to enter the fuel rail and fuel rail solenoid
threads after the fuel pressure solenoid has been removed from the fuel
rail.

2007 Dodge Nitro R/T

2007 ENGINE Fuel System - Nitro

Fig. 83: Exploded View Of Fuel Rail - 2.8L Diesel
Courtesy of CHRYSLER LLC

1. Position the fuel rail (2) into a soft jawed vise.

2. Inspect the sealing surfaces of the fuel pressure solenoid opening in the fuel rail. If any cuts or gouges are

present in the fuel rail pressure solenoid opening, replace the fuel rail.

3. Lubricate the fuel pressure solenoid sealing rings with clean diesel fuel. Do not allow dirt or debris to

come in contact with the fuel rail solenoid or the threads in the fuel rail.

WARNING:

Before working on an open fuel system, eliminate any source of sparks or
open flames near the work area, and do not smoke. Wash diesel fuel off
skin as soon as possible to avoid the risk of poisoning from inhaling and
swallowing fuel. Do not allow diesel fuel to come in contact with eyes,
otherwise, severe injury can result from contact with fuel. Pour fuels only
into suitable and appropriately marked containers. Wear protective
clothing whenever possible to avoid injury.

CAUTION: There is a special tightening procedure for the fuel rail solenoid that must

be followed along with the proper use of a torque wrench. Therefore the
fuel rail must be removed before installing the fuel pressure solenoid.

CAUTION: Do not reuse an existing fuel pressure solenoid. A new fuel pressure

solenoid must be installed any time the existing solenoid has been
removed from the fuel rail.

2007 Dodge Nitro R/T

2007 ENGINE Fuel System - Nitro