Ford F150 Pickup. Manual — part 1604

2003 ENGINE PERFORMANCE

Trouble Shooting - No Codes - Bi-Fuel - Gasoline/LPG

INTRODUCTION

This article contains bi-fuel system trouble shooting tests only. For gasoline or flex-fuel vehicles with EEC-V
systems, see TROUBLE SHOOTING - NO CODES - CNG, FLEX-FUEL & GASOLINE article. Always
retrieve Powertrain Control Module (PCM) DTCs before Alternate Fuel Control Module (AFCM) DTCs. If any
network "U" type DTCs are present, repair prior to PCM DTCs. If PCM DTCs are retrieved, go to
DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - CNG, FLEX-FUEL &
GASOLINE article and service DTCs as necessary. If AFCM DTCs are retrieved, go to DIAGNOSTIC
TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - BI-FUEL - GASOLINE/LPG article. If no
DTCs are present, perform SYMPTOM DIAGNOSIS under SYMPTOMS to diagnose driveability problems
existing when a hard fault code is not present. If all symptom tests check okay, perform INTERMITTENT
PROBLEM DIAGNOSIS under INTERMITTENTS.

For specific system or component testing procedures, see SYSTEM & COMPONENT TESTING - BI-FUEL
- GASOLINE/LPG article. For specifications, seeON-VEHICLE ADJUSTMENTS - TRUCKS article or
appropriate SERVICE & ADJUSTMENT SPECIFICATIONS article.

PRELIMINARY CHECKS

Check for vacuum leaks. Check air intake duct and air filter. Check ignition wiring. Check alternate fuel tank(s)
for adequate LPG level. Check wiring harness connector for poor connections. Check PCM, compuvalve,
sensors and actuators for damage. Check engine coolant for proper level and mixture. Check A/T fluid for
proper level and quality. Make all repairs before performing SYMPTOM DIAGNOSIS .

SYMPTOMS

NOTE:

Some driveability problems may have been corrected by manufacturer with a
revised computer calibration chip or computer control unit. Check with
manufacturer for latest chip or computer application.

NOTE:

Bi-fuel systems operating in Alternate (ALT) fuel mode (LPG) are gaseous-type
fuel systems that require a higher spark plug firing voltage to ignite fuel and
puts a higher load on vehicle ignition system. A secondary ignition system may
not operate well or may exhibit problems when running on alternate fuel; such
as backfiring or stalling, even though no problems exist while running on
gasoline.

CAUTION: When battery is disconnected, vehicle computer may lose memory data.

Driveability problems may exist until computer systems have completed a
relearn cycle. Before disconnecting battery, see COMPUTER RELEARN
PROCEDURES article in GENERAL INFORMATION.

2003 Ford Pickup F150

2003 ENGINE PERFORMANCE Trouble Shooting - No Codes - Bi-Fuel - Gasoline/LPG

2003 Ford Pickup F150

2003 ENGINE PERFORMANCE Trouble Shooting - No Codes - Bi-Fuel - Gasoline/LPG

SYMPTOM DIAGNOSIS

Symptom checks cannot be used properly unless problem occurs while vehicle is being tested. To reduce
diagnostic time, retrieve Powertrain Control Module (PCM) and Alternate Fuel Control Module (AFCM)
DTCs. Ensure QUICK TEST in SELF-DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article or
QUICK TEST in SELF-DIAGNOSTICS - BI-FUEL - GASOLINE/LPG article is performed before
diagnosing a symptom. The following symptoms are available for diagnosis:

z

ROUGH OR ROLLING IDLE, STALLS, MISSES, HESITATION OR SURGE

z

HARD START OR LONG CRANK

z

NO START/NORMAL CRANK - ALT FUEL MODE

z

NO START/NORMAL CRANK - GASOLINE MODE

z

SLOW RETURN TO IDLE

z

FAST IDLE (DIESELS/RUNS ON)

z

LOW IDLE (STALLS ON DECELERATION)

z

BACKFIRES

z

LACK/LOSS OF POWER

z

SPARK KNOCK

z

POOR FUEL ECONOMY

z

VEHICLE FAILS EMISSIONS/EMISSIONS COMPLIANCE

ROUGH OR ROLLING IDLE, STALLS, MISSES, HESITATION OR SURGE

z

Check fuel delivery system. See TEST HC: FUEL DELIVERY SYSTEM under SYSTEM TESTS in
SELF-DIAGNOSTICS - BI-FUEL - GASOLINE/LPG article.

z

Check secondary ignition system. See TEST JB: SECONDARY IGNITION under SYSTEM TESTS in
SELF-DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article.

z

Check exhaust system for restriction. See TEST HF: CATALYST EFFICIENCY MONITOR &
EXHAUST SYSTEMS under SYSTEM TESTS in SELF-DIAGNOSTICS - CNG, FLEX-FUEL &
GASOLINE article.

z

Check PCV system. See TEST HG: PCV SYSTEM under SYSTEM TESTS in SELF-DIAGNOSTICS -
CNG, FLEX-FUEL & GASOLINE article.

NOTE:

Check vehicle for any driveability symptoms in gasoline mode. Repair any
driveability symptoms in gasoline mode before diagnosing ALT fuel system. Go
to SYMPTOM DIAGNOSIS under SYMPTOMS in TROUBLE SHOOTING - NO
CODES - CNG, FLEX-FUEL & GASOLINE article.

NOTE:

If engine stalls after start up and base gasoline engine system has sufficient
fuel, diagnose for a no-start. Go to TEST AC: NO START - ALT FUEL SWITCH
INDICATOR IS ON, THEN OFF under SYSTEM TESTS in SELF-DIAGNOSTICS -
BI-FUEL - GASOLINE/LPG article.

2003 Ford Pickup F150

2003 ENGINE PERFORMANCE Trouble Shooting - No Codes - Bi-Fuel - Gasoline/LPG

z

Check automatic transmission operation. See appropriate DIAGNOSIS article in AUTOMATIC
TRANSMISSIONS.

z

Check EVAP emission system for blockages (engine stalls) or leaks (excessive fuel odor). See SYSTEM
TESTS (EVAPORATIVE EMISSION) in SELF-DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE
article.

z

Check engine mechanical condition. Check compression, camshaft, valve train components, etc. Repair
as necessary. See appropriate article in ENGINES.

z

Check air intake system. See TEST HU: AIR INTAKE SYSTEM under SYSTEM TESTS in SELF-
DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article.

z

Check Mass Air Flow (MAF) sensor and related circuits. See TEST DC: MASS AIRFLOW SENSOR
under SYSTEM TESTS in SELF-DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article.

z

Additional Checks

Check for correct PCM Vehicle Identification (VID) block information. See FLASH VEHICLE
IDENTIFICATION BLOCK PROCEDURE under PROGRAMMING PCM in SELF-DIAGNOSTICS
- CNG, FLEX-FUEL & GASOLINE article. Check drivelines. Check charging system. See appropriate
GENERATORS & REGULATORS article in ELECTRICAL. Check traction control system (if
equipped). See appropriate ANTI-LOCK article in BRAKES. Check A/C system for surge with A/C on,
and check A/C compressor diode, if equipped, for rolling idle. See appropriate AUTOMATIC or
MANUAL A/C-HEATER SYSTEMS article in AIR CONDITIONING & HEATING. Check speed
control system for surge with speed control on. See appropriate CRUISE CONTROL SYSTEMS article
in ACCESSORIES & EQUIPMENT. Ensure engine RPM/speed limiting functions of PCM are operating
properly. Check for incorrect high vehicle speed signal. If no problems are indicated, return to
SYMPTOM DIAGNOSIS to identify any additional symptoms or check for intermittent faults. See
TEST Z: INTERMITTENT under SYSTEM TESTS in SELF-DIAGNOSTICS - CNG, FLEX-FUEL &
GASOLINE article.

HARD START OR LONG CRANK

z

Check battery condition and amperage draw. See appropriate GENERATORS & REGULATORS article
in ELECTRICAL.

z

Check secondary ignition system. See TEST JB: SECONDARY IGNITION under SYSTEM TESTS in
SELF-DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article.

z

Check fuel delivery system. See TEST HC: FUEL DELIVERY SYSTEM under SYSTEM TESTS in
SELF-DIAGNOSTICS - BI-FUEL - GASOLINE/LPG article.

z

Check air intake system. See TEST HU: AIR INTAKE SYSTEM under SYSTEM TESTS in SELF-
DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article.

z

Check exhaust system for restriction. See TEST HF: CATALYST EFFICIENCY MONITOR &
EXHAUST SYSTEMS under SYSTEM TESTS in SELF-DIAGNOSTICS - CNG, FLEX-FUEL &

NOTE:

Alternate fuel engine cranking time is normally longer than gasoline engine
cranking time. Check vehicle for add-on anti-theft devices that may disable
starting system. If equipped, disable system before continuing.

2003 Ford Pickup F150

2003 ENGINE PERFORMANCE Trouble Shooting - No Codes - Bi-Fuel - Gasoline/LPG

GASOLINE article.

z

Check EVAP emission system for blockages (engine stalls) or leaks (excessive fuel odor). See SYSTEM
TESTS (EVAPORATIVE EMISSION) in SELF-DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE
article.

z

Check PCV system. See TEST HG: PCV SYSTEM under SYSTEM TESTS in SELF-DIAGNOSTICS -
CNG, FLEX-FUEL & GASOLINE article.

z

Check starting system. See appropriate STARTERS article in ENGINES.

z

Visually inspect Mass Air Flow (MAF) sensor for contamination.

z

If no concern is found, check for intermittent faults. See TEST Z: INTERMITTENT under SYSTEM
TESTS in SELF-DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article.

NO START/NORMAL CRANK - ALT FUEL MODE

z

If ALT fuel switch indicator is always off, see TEST AB: NO START - ALT FUEL SWITCH
INDICATOR OFF under SYSTEM TESTS in SELF-DIAGNOSTICS - BI-FUEL - GASOLINE/LPG
article.

z

If ALT fuel switch indicator is on then goes off, see TEST AC: NO START - ALT FUEL SWITCH
INDICATOR IS ON, THEN OFF under SYSTEM TESTS in SELF-DIAGNOSTICS - BI-FUEL -
GASOLINE/LPG article.

z

If ALT fuel switch indicator is always on, see TEST AD: NO START - ALT FUEL SWITCH
INDICATOR IS ON STEADY under SYSTEM TESTS in SELF-DIAGNOSTICS - BI-FUEL -
GASOLINE/LPG article.

z

If ALT fuel switch indicator is flashing, see TEST UC: SIGNAL LINK FAULT under SYSTEM
TESTS in SELF-DIAGNOSTICS - BI-FUEL - GASOLINE/LPG article.

z

If engine is still a no-start after completing previous tests, see TEST KE: IDLE AIR CONTROL
VALVE under SYSTEM TESTS in SELF-DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article.

z

Check exhaust system for restriction. See TEST HF: CATALYST EFFICIENCY MONITOR &
EXHAUST SYSTEMS under SYSTEM TESTS in SELF-DIAGNOSTICS - CNG, FLEX-FUEL &
GASOLINE article.

z

Check engine mechanical condition. Check compression, camshaft, valve train components, etc. and
repair as necessary. See appropriate article in ENGINES. If no concern is found, check for intermittent
faults. See TEST Z: INTERMITTENT under SYSTEM TESTS in SELF-DIAGNOSTICS - CNG,
FLEX-FUEL & GASOLINE article.

NO START/NORMAL CRANK - GASOLINE MODE

CAUTION: Extended cranking due to a no-start condition, can load exhaust system

with raw fuel, which may ruin catalytic converter after engine is started.

NOTE:

If ALT fuel switch indicator illuminates and then goes off, vehicle may switch
automatically to gasoline mode. Check vehicle for add-on anti-theft devices that
may disable ignition system. If equipped, disable system before continuing.

2003 Ford Pickup F150

2003 ENGINE PERFORMANCE Trouble Shooting - No Codes - Bi-Fuel - Gasoline/LPG