Ford F150 Pickup. Manual — part 1326

Fig. 6: Checking Fuel Tank Solenoid Gap
Courtesy of FORD MOTOR CO.

FUEL SYSTEMS

FUEL SYSTEM PRECAUTIONS (CNG)

CAUTION: When battery is disconnected, vehicle computer and memory systems

may lose memory data. Driveability problems may exist until computer
systems have completed a relearn cycle. See COMPUTER RELEARN
PROCEDURES article in GENERAL INFORMATION before disconnecting
battery.

WARNING:

The fuel system operates under high pressure and remains pressurized
after engine shutdown. The fuel system pressure must be relieved before
any fuel-related components are serviced. Failure to relieve the fuel
pressure could result in personal injury or property damage.

WARNING:

The status (stuck open, stuck closed, or good) of each fuel tank solenoid
valve must be identified prior to venting the fuel system or personal injury
or property damage may result.

2003 Ford Pickup F150

2003 ENGINE PERFORMANCE Removal & Installation - F150 Pickup - CNG

FUEL SYSTEM PRESSURE RELEASE

Compressed Natural Gas Fuel Line Venting

Engine Runs

1. Close each manual lock-down valve jackscrew on the fuel tank solenoid valves. See Fig. 7 . Disconnect

the Fuel Rail Pressure (FRP) sensor electrical connector.

2. Start the engine and allow it to idle until it stalls. Once the engine stalls, crank the engine for an

additional 15 seconds.

WARNING:

Do not vent an entire fuel tank by using the fuel line venting procedure, as
damage to the fuel supply manifold Schrader valve will result, with the
possibility of personal injury or property damage.

WARNING:

Do not modify the system configuration or components, or install
components or parts not specially designed for use with natural gas. Ford
Motor Company has specially designed the materials, components and
system configuration for the 5.4L F150 Pickup natural gas vehicles, and
each particular system is precisely calibrated for efficient operation. The
use of different parts or materials can produce an untested configuration
that could result in fire or personal injury, or cause engine damage.

WARNING:

Eye and ear protection are required to be worn during venting or removal
and installation of fuel system components. Failure to follow these
manuals may result in personal injury.

CAUTION: Do not vent any fuel tank unless the fuel tank or the fuel tank solenoid

valve is damaged or inoperative and a new fuel tank solenoid valve or fuel
tank must be installed. Unnecessary venting of good tanks can cause
damage to the fuel tank solenoid valve.

NOTE:

It is recommended that venting be carried out with a vent stack.

WARNING:

Fuel supply lines remain pressurized after engine shutdown. Ensure no
open flame of any type is present. Flammable gases may be present and
ignite, resulting in possible injury. Always release (vent) fuel pressure
before disconnecting any fuel injection-related component downstream of
fuel tank shutoff solenoids. DO NOT vent fuel system indoors.

NOTE:

Running the engine with the FRP sensor electrical connector
disconnected will generate a DTC that will have to be cleared.

2003 Ford Pickup F150

2003 ENGINE PERFORMANCE Removal & Installation - F150 Pickup - CNG

3. Slightly loosen the FRP sensor to release the residual pressure from the fuel rail. Tighten and reconnect

the FRP sensor.

4. Using the scan tool, access the FRP PID. The FRP PID should indicate less than 5 psi. If so, the fuel

system may be opened and serviced. If not, repeat the procedure.

Engine Does Not Run

1. Close each manual lock-down valve jackscrew on the fuel tank solenoid valves. See Fig. 7 .

2. Slightly loosen the low pressure fuel line fitting until the fuel starts to escape. After the fuel is evacuated,

disconnect the fitting, install new "O" rings, lubricate the "O" rings with engine oil, and connect the
fitting.

WARNING:

This step in the procedure will vent a very slight amount of residual
pressure to the atmosphere. Use care to prevent the combustion of
escaping fuel. Smoking, open flames or any kind of arcing must be
avoided. Carry out this operation only in a well-ventilated area.
Failure to follow these manuals may result in personal injury.

NOTE:

If the vehicle is being serviced for an FRP sensor DTC, the FRP PID
reading may not indicate actual pressure in the fuel rail.

WARNING:

This step in the procedure will vent pressure to the atmosphere. Use
care to prevent the combustion of escaping fuel. Smoking, open
flames or any kind of arcing must be avoided. Carry out this
operation only in a well-ventilated area. Failure to follow these
manuals may result in personal injury.

2003 Ford Pickup F150

2003 ENGINE PERFORMANCE Removal & Installation - F150 Pickup - CNG

Fig. 7: Identifying Fuel Tank Solenoid Components
Courtesy of FORD MOTOR CO.

2003 Ford Pickup F150

2003 ENGINE PERFORMANCE Removal & Installation - F150 Pickup - CNG