Ford F150 Pickup. Instruction - part 1166

Fig. 57: Installing Fuel Fill Line Onto Fuel Fill Valve 
Courtesy of FORD MOTOR CO. 

FUEL SYSTEM LEAK TEST 

Special Tool(s) 

 

2003 Ford Pickup F150 

2003 GENERAL INFORMATION Fuel System - General Information - Natural Gas - F150 Pickup

  

Fig. 58: Identifying Special Tool(s) 
Courtesy of FORD MOTOR CO. 

Fuel Injection Supply Manifold & Fuel Injectors 

1. Remove the fuel pump relay from the power distribution box.  

2. Construct a jumper wire from 152 mm (6 inches) of 18 gauge wire and two spade terminal ends.  

3. Jumper the fuel pump relay circuit from Socket 87 to Socket 30. 

NOTE:

After the vehicle has soaked for several hours, a very slight natural gas 
smell may emanate from within the intake manifold and intake air system. 
This is normal, as the fuel injectors leak down from the fuel injection 
supply manifold to the intake manifold over several hours.

 

2003 Ford Pickup F150 

2003 GENERAL INFORMATION Fuel System - General Information - Natural Gas - F150 Pickup

  

Fig. 59: Jumpering Fuel Pump Relay Circuit 
Courtesy of FORD MOTOR CO. 

4. Remove the jumper wire.  

5. Install the fuel pump relay into the power distribution box.  

6. Check the spring lock coupling and the fuel injection supply manifold to fuel injector connections for 

leaks, using the combustible gas detector.  

7. If a leak is detected, verify the connection is engaged properly, then retest.  

8. If the leak remains, repair as necessary and retest.  

Fuel Tanks, Filter & Lines 

1. Check the fuel tank(s), coalescer/filter and fuel line connections for leaks, using the combustible gas 

detector.  

2. If a leak is detected, verify that the fittings are tightened properly, then retest.  

3. If the leak remains, inspect the O-ring, O-ring land and sealing surfaces for any damage, distortion or 

NOTE:

Verify system pressure is at least 10,343 kPa (1500 psi). If system pressure 
is below 10,343 kPa (1500 psi), refuel the vehicle.

 

2003 Ford Pickup F150 

2003 GENERAL INFORMATION Fuel System - General Information - Natural Gas - F150 Pickup

  

contamination.  

4. Repair as necessary and retest.  

FUEL TANK INSPECTION 

1. Raise and support the vehicle.  

2. Examine the vehicle underbody and chassis in the general area near the fuel tank(s) for any indication of 

collision damage, malfunction, fire or excessive mud/dirt accumulation.  

3. Examine the fuel tank stone/heat shield for any indication of collision damage, malfunction, fire or 

excessive mud/dirt accumulation.  

4. Remove the fuel tank stone/heat shield.  

5. Examine the fuel tank(s) and the stone/heat shield interior for any foreign objects (such as stones or 

gravel) or foreign materials (such as mud, salt, liquids or chemical residue).  

6. Remove any foreign material, using only a clean, dry cloth. Remove all foreign objects. Do not use water 

or any cleaners.  

7. Examine the fuel tank labels for the tank expiration date. Use a light and mirror to access labels hidden 

from normal view. If the expiration date has been exceeded, condemn the tank, using the procedure in 
step 14 .  

8. Inspect the tank sidewall and dome ends, following the general guidelines set forth in the Compressed 

Gas Association Pamphlet C6.2. Inspect the tank(s) for the following: 

z

abrasions  

z

dents  

z

cracking, blistering or peeling of clear coating  

z

corrosion  

z

cracks or gouges in the metal dome  

z

cracks in the fiberglass overwrap  

z

impact damage (cracking) in the fiberglass overwrap  

z

cuts or gouges in the fiberglass overwrap  

z

exposed fibers  

z

delamination (separating) of the fiberglass overwrap  

z

discoloration of the fiberglass overwrap  

z

fire or heat damage, such as charring or discoloration  

9. If any flaws are detected, measure the depth and length of the flaw in accordance with the Compressed 

NOTE:

The following procedure is an in-vehicle, visual inspection for natural gas 
fuel cylinders. A 1-year/19,310-km (12,000-mile) (whichever occurs first) 
inspection interval is assumed.

NOTE:

The Compressed Natural Gas Pamphlet C6.2 can be obtained from the 
Compressed Gas Association, Inc., 1725 Jefferson Davis Highway, 
Arlington, VA 22202-4102.

 

2003 Ford Pickup F150 

2003 GENERAL INFORMATION Fuel System - General Information - Natural Gas - F150 Pickup