Ford F150 Pickup. Instruction - 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 instruction 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 
instructions 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 instruction 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 instructions 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 
instructions 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