Ford F150 Pickup. Instruction - part 1218

BASE IGNITION TIMING 

FUEL SYSTEMS 

FUEL INJECTORS 

FUEL INJECTOR RESISTANCE 

FUEL PUMP 

FUEL PRESSURE SPECIFICATIONS 

IDLE SPEED & MIXTURE 

NOTE:

On all models with distributorless electronic ignition, manufacturer does not 
recommend checking ignition timing, as faulty readings are common and timing 
is not adjustable.

Application

Degrees BTDC

All

10

Application

(1)

 Resistance - Ohms

4.2L

11.4-12.6

4.6L

13.8-15.2

5.4L

13.8-15.2

5.4L CNG

4-6

6.8L

11-18

(1)

Resistance values are for a single injector.

NOTE:

Fuel pump performance is a measurement of fuel pressure and volume 
availability, not regulated fuel pressure.

Application

(1)

 psi (kPa)

CNG Engines

80-120 (276-827)

Diesel Engine

6.0L

45-55 (310-379)

7.3L

45-80 (310-552)

Gasoline Engines

4.2L, 4.6L & 6.8L

30-45 (207-310)

5.4L

30-55 (207-379)

(1)

With key on and engine off and fuel pump running.

NOTE:

Idle speed and mixture are not adjustable. For additional information, see 
appropriate THEORY & OPERATION article.

 

2003 Ford Pickup F150 

2003 ENGINE PERFORMANCE Service & Adjustment Specifications - Excursion & Pickup

  

THROTTLE POSITION SENSOR 

TP SENSOR OUTPUT 

NOTE:

Throttle Position (TP) sensor is not serviceable. TP sensor may also be referred 
to as Accelerator Pedal (AP) sensor. If TP sensor service is required, perform 
TP sensor related system test. See appropriate SELF-DIAGNOSTICS article.

Throttle Angle Degrees

(1)

 Volts

Clockwise

20

1.00

40

2.00

60

3.00

80

3.80

100

4.65

Counterclockwise

0

1.00

-20

2.00

-40

3.00

-60

3.80

-80

4.65

(1)

Throttle position may vary by 6 percent.

 

2003 Ford Pickup F150 

2003 ENGINE PERFORMANCE Service & Adjustment Specifications - Excursion & Pickup

  

2003 ENGINE PERFORMANCE

Basic Diagnostic Procedures - Trucks - Except Diesel 

INTRODUCTION 

The following diagnostic steps will help prevent overlooking a simple problem. The first step in diagnosing any 
driveability problem is verifying the symptom(s) with a test drive under the conditions the problem reportedly 
occurred. 

Before proceeding with diagnostics, check for applicable Technical Service Bulletins (TSBs). If there are no 
applicable TSBs, perform QUICK TEST under SELF-DIAGNOSTICS - EEC-V - CNG, FLEX-FUEL & 
GASOLINE to identify Diagnostic Trouble Codes (DTCs). If no DTCs are present or only pass codes are found 
during self-diagnostics and symptom is present, proceed to TROUBLE SHOOTING - NO CODES - EEC-V -
CNG, FLEX-FUEL & GASOLINE article for diagnosis by symptom. 

PRELIMINARY INSPECTION & ADJUSTMENTS 

VISUAL INSPECTION 

Visually inspect all electrical wiring, looking for chafed, stretched, cut or pinched wiring. Ensure electrical 
connectors fit tightly and are not corroded. Ensure vacuum hoses are properly routed and are not pinched or cut. 
Inspect air induction system for possible vacuum leaks. 

MECHANICAL INSPECTION 

Compression 

Check engine compression with engine at normal operating temperature, all spark plugs removed (on dual 
plugs, remove exhaust side only), and throttle wide open. Ensure crankcase is full and oil is of correct viscosity. 
With compression gauge installed, use remote starter switch to crank engine. Crank engine at least 5 
revolutions, and record highest reading. Repeat procedure for all cylinders, using approximately same number 
of revolutions. Lowest compression reading should not be less than 75 percent of highest compression reading. 
No cylinder compression reading should be less than 100 psi (7 kg/cm

2

 ). 

Exhaust System Backpressure 

NOTE:

References to Econoline include Cutaway and RV Cutaway. References to F250-
550 include Cab & Chassis.

WARNING:

Because fuel injectors on many models are triggered by the ignition 
switch, DO NOT use ignition switch during compression tests on fuel 
injected vehicles. Use a remote starter to crank engine to prevent fire 
hazard or engine oiling system contamination.

 

2003 Ford Pickup F150 

2003 ENGINE PERFORMANCE Basic Diagnostic Procedures - Trucks - Except Diesel

  

 

2003 Ford Pickup F150 

2003 ENGINE PERFORMANCE Basic Diagnostic Procedures - Trucks - Except Diesel

  

Using a vacuum or pressure gauge, check exhaust system. Remove Heated Oxygen Sensor (HO2S) or air 
injection check valve (if equipped). Connect a 0-5 psi pressure gauge. Backpressure should be less than 3 psi at 
idle and less than 8 psi at wide open throttle. If exhaust system backpressure is greater than specified, exhaust 
system or catalytic converter is plugged. 

If using a vacuum gauge, connect vacuum gauge hose to intake manifold vacuum port, and start engine. 
Observe vacuum gauge. Open throttle part way and hold steady. If vacuum gauge reading slowly drops after 
stabilizing, check exhaust system for restrictions. 

FUEL SYSTEMS 

PRELIMINARY CHECKS 

Ensure following systems and components are in good condition and operating properly before diagnosing 
problems in fuel injection system:  

z

Check battery and charging system condition.  

z

Check all wiring and vacuum connections.  

z

Check air cleaner and ducting.  

z

Check state of tune.  

z

Check fuel delivery system.  

z

Check cooling system.  

z

Check inertia fuel shutoff switch.  

z

Check for blown head gasket (liquid in cylinder).  

z

Check fuel tank contents and fuel gauge accuracy.  

z

Check for dirt, water or other contamination in fuel.  

z

Check fuel lines and fittings for leaks.  

z

Check fuel delivery system for proper pressure and volume.  

z

Check for inoperative fuel injectors.  

z

Check for improperly installed electronic equipment such as anti-theft system, CB radio, cellular 
telephone or stereo.  

FUEL SYSTEM PRESSURE RELEASE 

NOTE:

For fuel system diagnosis on Natural Gas Vehicles (NGV), see TEST HA: 
NATURAL GAS FUEL CONTROL and TEST HB: NATURAL GAS FUEL DELIVERY 
SYSTEM in SELF-DIAGNOSTICS - EEC-V - CNG, FLEX-FUEL & GASOLINE 
article or TEST H: FUEL CONTROL in SELF-DIAGNOSTICS - EEC-V - BI-FUEL 
article.

WARNING:

Always relieve fuel pressure before disconnecting any component under 
fuel pressure. DO NOT allow fuel to contact engine or electrical 

 

2003 Ford Pickup F150 

2003 ENGINE PERFORMANCE Basic Diagnostic Procedures - Trucks - Except Diesel