Ford F150 Pickup. Instruction - part 1151

Fig. 56: Locating Adjustment Screw Holes On Top Of Tuning Tee Assembly 
Courtesy of FORD MOTOR CO. 

15. Turn the tuning tee adjustment screw identified in step 13 one complete turn clockwise and repeat steps 

10 through 12.  

16. Retrieve and compare the current graphed PCM PIDs O2S11 and O2S21 data with the previous data. If 

the determined PCM O2S PID from the previous graphed data continues to have the longer high state 
time, repeat steps 15 and 16.  

17. If the determined PCM O2S PID from the previous graphed data now has a shorter high state time, turn 

the corresponding tuning tee adjustment screw counterclockwise 1/2 turn and repeat steps 10 through 12. 

18. Retrieve and compare the current recorded graphed PCM PIDs O2S11 and O2S21 data. If necessary, 

continue to turn the same adjustment screw by 1/4 and 1/8 turn increments clockwise or counterclockwise 
as described in step 14 repeating steps 10 through 12 with each adjustment until both O2S PIDs display 
equal high state time. 

 

2003 Ford Pickup F150 

2003 GENERAL INFORMATION Fuel System-General Information-Bi-Fuel - F150 Pickup

  

Fig. 57: O2S PIDs Display 
Courtesy of FORD MOTOR CO. 

19. When the retrieved PCM PIDs O2S11 and O2S21 data display equal high state time, the alternate fuel 

system is correctly tuned and no further adjustment is required. Document the following information: 
VIN, date, lead technician, assistant, O2S bank number adjusted, required number of turns to adjustment 
screw (to nearest 1/8th turn).  

20. Turn the ignition switch to the OFF position and remove the vacuum gauge and restore the intake vacuum 

system.  

21. Paint mark the tuning tee adjustment screw positions and seal the access hole with a manufacturers sensor 

safe sealant. Cover and label the adjustment screw cavities indicating that the alternative fuel system 
tuning procedure has been performed. Update all necessary vehicle inspection labels and placards. 

 

2003 Ford Pickup F150 

2003 GENERAL INFORMATION Fuel System-General Information-Bi-Fuel - F150 Pickup

  

2003 GENERAL INFORMATION

Fuel System - General Information - Natural Gas - F150 Pickup 

SPECIFICATIONS 

TORQUE SPECIFICATIONS 

Fig. 1: Fuel System - Natural Gas Torque Specifications (1 Of 2) 
Courtesy of FORD MOTOR CO. 

Fig. 2: Fuel System - Natural Gas Torque Specifications (2 Of 2) 
Courtesy of FORD MOTOR CO. 

DESCRIPTION & OPERATION 

FUEL SYSTEM 

 

2003 Ford Pickup F150 

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

  

 

2003 Ford Pickup F150 

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

  

When repairing the fuel system, observe the following information:  

z

All 5.4L CNG engines use a closed-type Positive Crankcase Ventilation (PCV) system and an exhaust 
emission system to control engine emissions within government specifications.  

z

To maintain the required exhaust emission levels, the fuel system must be kept in proper operating 
condition.  

z

The Natural Gas fuel system must be adjusted to specifications. Refer to SERVICE & ADJUSTMENT 
SPECIFICATIONS .  

z

Additional engine performance checks are required to keep the exhaust emissions at the specified 
minimum pollutant level.  

This article covers general procedures related directly to the fuel system. 

Always refer to an appropriate Master Parts Catalog for parts usage and interchangeability before replacing any 
component of the fuel system. 

Coalescer/Filter 

Natural gas vehicles are equipped with a coalescer/filter assembly. The coalescer/filter assembly separates, 
filters and stores any contamination and moisture found in the fuel system, preventing moisture from entering 
the engine. 

WARNING:

Do not modify the system configuration or components, or replace 
components with 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 F-250 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:

It is important that your natural gas vehicle be properly maintained by 
ford natural gas trained personnel. If a problem occurs, it is important 
that properly trained personnel diagnose the cause. If the problem relates 
to the fuel system, proper part replacement is imperative to keep your 
vehicle operating at normal performance. Natural gas components and 
gasoline fuel components are not interchangeable. If your vehicle is not 
serviced in accordance with natural gas-fueled vehicle procedures, 
damage can occur and your warranty may be invalidated.

NOTE:

All standard production components and systems receive routine repair under 
base warranty procedures.

 

2003 Ford Pickup F150 

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