Ford F150 Pickup. Manual — part 1341

heavier than air. The heavier gas can displace or push fresh air out of an area. In large quantities, propane can
displace enough oxygen to make the surrounding air unfit to breathe and possibly cause illness. If a person
breathes propane gas or air that lacks oxygen due to presence of propane gas, headache, dizziness, and
weakness in the extremities can occur. In severe cases, prolonged breathing of propane-fouled air can cause
suffocation. In the event of illness from inhaling propane gas, move victim immediately to fresh air and contact
a physician or medical emergency personnel for artificial respiration or other required treatment.

DO NOT needlessly vent propane fuel during service, and do not open the 80 percent stop-fill valve while a
vehicle is inside a building. When servicing fuel system, follow recommended procedures to shut off fuel tanks
and run engine out of fuel before disconnecting fuel system components. See FUEL SYSTEM PRESSURE
RELEASE under FUEL SYSTEMS in REMOVAL & INSTALLATION - F150 PICKUP - BI-FUEL -
GASOLINE/LPG article. If fuel tank(s) are being serviced, have fuel evacuated by trained personnel at a local
propane fuel station. LPG fuel vaporizes at normal barometric pressure at temperatures above -44°F (-42°C),
and expands to 270 times its volume as a liquid. Unnecessary venting of LPG fuel can create fire and health
hazards which could cause personal injury or death. Be alert for situations that may cause LPG fuel system to
vent fuel. These include extremely hot days, parking near a space heater, or hoisting a vehicle up near a ceiling
heater. Release of LPG fuel in a confined area through pressure relief valve could occur. Release of LPG fuel in
a confined area could result in an accumulation of flammable vapors. If fuel is vented near a heat source, a fire
or explosion could occur.

DO NOT use paint drying ovens for LPG fueled vehicles. Heat from paint drying ovens will increase pressure
in fuel tanks and could cause venting of LPG fuel vapor into oven and result in a fire from heat or sparks in
electrical equipment. If fuel is confined inside an oven, an explosion may occur. If a confined area, such as a
lubrication pit, has been subjected to LPG gas, the area should be inspected for adequate oxygen levels by a
local health department before being entered, or personal injury or death may occur. LPG fuel system pressure
must be relieved before any component can be removed. Fuel tanks must be evacuated prior to tank removal.
Removal of components without pressure relief or tank evacuation can cause LPG fuel to escape and cause
injury or death.

Inertia Fuel Shutoff Switch Reset Procedure

Turn ignition off. Check for fuel leaks in engine compartment. If no leak is present, reset IFS switch by pushing
reset button on top of switch. Turn ignition switch to ON or START position for a few seconds, then to OFF
position again. Again, check for leaking fuel.

NOTE:

Fuel system is designed to vent excess fuel vapor pressure in high ambient
temperatures, such as those experienced in desert locations. Pressure relief
valve will vent fuel and automatically reset itself. Observe all warnings when
performing LPG leak test. See LEAK TEST - ALL BI-FUEL VEHICLES under
FUEL SYSTEMS.

WARNING:

If you see or smell gasoline at any time other than during fueling, DO NOT
reset Inertia Fuel Shutoff (IFS) switch.

NOTE:

With IFS in CLOSED position, reset button can be depressed an additional 1/16"
against the spring.

2003 Ford Pickup F150

2003 ENGINE PERFORMANCE System & Component Testing - Bi-Fuel - Gasoline/LPG

FUEL SYSTEMS

FUEL SYSTEM PRESSURE RELEASE

LPG fuel pressure must be released prior to any fuel system service. To release LPG fuel pressure, see FUEL
SYSTEM PRESSURE RELEASE under FUEL SYSTEMS in REMOVAL & INSTALLATION - F150
PICKUP - BI-FUEL - GASOLINE/LPG article. Failure to follow these manuals may result in personal
injury.

LEAK TEST - ALL BI-FUEL VEHICLES

Ensure fuel tank is filled to half of maximum pressure. Pressurize the entire fuel system. Beginning with the fill
valve, follow the entire system applying a quantity of mild soapy water to each fitting or component seam
through to fuel injectors. Leaks in the system will exhibit soapy bubbles. If any leaks are discovered, evacuate
fuel system. See FUEL SYSTEM PRESSURE RELEASE under FUEL SYSTEMS in REMOVAL &
INSTALLATION - F150 PICKUP - BI-FUEL - GASOLINE/LPG article. Repair any leaks detected. Fill the
fuel tank to full pressure. Repeat soapy water application and repair any leaks discovered.

FUEL RAIL TUNING ADJUSTMENT

WARNING:

Before performing any tests or diagnostics on LPG components or
systems, read all cautions and warnings in CNG/LPG SAFETY
PRECAUTIONS article in GENERAL INFORMATION.

WARNING:

LPG bi-fuel systems are kept up to 3000 psi (211 kg/cm

2

) upstream of fuel

pressure regulator. Use care when servicing LPG fuel systems.

WARNING:

Bi-fuel system pressure must be relieved prior to any leak repair or
personal injury may occur.

NOTE:

DO NOT use Rotunda Combustible Gas Detector on bi-fuel vehicles. Follow all
safety precautions. See FUEL SYSTEM SAFETY PRECAUTIONS and/or
CNG/LPG SAFETY PRECAUTIONS article in GENERAL INFORMATION.

WARNING:

Certain steps in this procedure require the vehicle to be running, in gear
and the engine accelerated. Be sure that the parking brake is fully set and
the wheels are correctly chocked. Take all necessary precautions to avoid
injury and property or equipment damage.

WARNING:

The alternative fuel (CNG or LPG) lines and components are pressurized.
Use care when servicing the system and take all necessary precautions to
avoid personal injury. Always follow all applicable procedures concerning
fuel leak testing and fuel system inspection.

2003 Ford Pickup F150

2003 ENGINE PERFORMANCE System & Component Testing - Bi-Fuel - Gasoline/LPG

1. Place the vehicle in an appropriate service bay, set the parking brake, and correctly place wheel chocks

both in front of and behind the front wheels. Connect the exhaust to a vacuum exhaust system and
provide adequate ventilation.

2. Select the OFF position of the ignition switch, and the ALT position of the ALT fuel selection switch.

3. Connect the vacuum/pressure tester to an appropriate source of intake manifold vacuum.

4. Connect the New Generation STAR (NGS) Tester to the vehicle diagnostic Data Link Connector (DLC).

Turn the ignition switch to the ON position. Select, monitor, and record Powertrain Control Module
(PCM) data PIDs ECT, O2S11, and O2S21.

5. Start and run the engine while monitoring the PCM PID ECT. Allow the engine to warm up until the

PCM PID ECT indicates 190°F.

6. Select, monitor, and record the Alternative Fuel Control Module (AFCM) PID MAP and vacuum. Place

the transmission gear in reverse while applying the brake pedal then slowly apply pressure to the
accelerator pedal. Continue to accelerate until the AFCM PID MAP indicates 7.3-7.4 psi and record the
vacuum. This vacuum value point will be used in the remaining procedure steps as the "tuning point".

7. Allow the accelerator to return to the idle position and place the transmission gear in the park position.

8. Locate the two adjustment screw holes on the top of the tuning tee assembly, remove any sealant and

access the adjustment screws. See Fig. 3 .

WARNING:

This step requires the vehicle to be running, in gear and the engine
accelerated. Be sure that the parking brake is fully set and the
wheels are correctly chocked. Take all necessary precautions to
avoid injury and property or equipment damage.

2003 Ford Pickup F150

2003 ENGINE PERFORMANCE System & Component Testing - Bi-Fuel - Gasoline/LPG

Fig. 3: Locating Tuning Tee Assembly Adjustment Screws
Courtesy of FORD MOTOR CO.

9. Position both tuning tee adjustment screws to their "neutral" state by turning them counterclockwise with

a slotted screwdriver until the screw head tops are flush with the top of the tuning tee and then turning
them clockwise two complete turns.

10. With the engine at idle speed and the transmission gear in the park position, select the NGS GRAPH

option. Record ten seconds of data from PCM PIDs O2S11 and O2S21 (1 and 2). Retrieve the recorded
data and identify which of the OS2 signals displays the longest high state time (1). See Fig. 4 .

WARNING:

Never remove the tuning tee adjustment screws while the low
pressure fuel lines are pressurized. Use caution when setting the
adjustment screws. If the adjustment screws become dislodged
from the tuning tee serious personal injury may result.

2003 Ford Pickup F150

2003 ENGINE PERFORMANCE System & Component Testing - Bi-Fuel - Gasoline/LPG