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Ford F150 Pickup. Instruction - part 1603

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.

SPARK KNOCK

Check cooling system for overheating. If cooling system is overheating, repair as necessary. See
appropriate ELECTRIC COOLING FANS article in ENGINE COOLING.

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

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

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

Check Knock Sensor (KS). See TEST DG: KNOCK SENSOR under SYSTEM TESTS in SELF-
DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article.

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

Visually inspect engine oil quality. Replace if necessary.

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.

POOR FUEL ECONOMY

Connect scan tool to Data Link Connector (DLC). Turn ignition on. Using scan tool, access PCM and
select DPFEGR (if equipped), LONGFT1, LONGFT2 and VPWR PIDs from PID/DATA MONITOR &
RECORD menu. See appropriate PIN VOLTAGE/PID VALUE CHARTS article. DPFEGR PID value
should be within .15 volt of Key On Engine Off (KOEO) value. If DPFEGR PID value is not as specified,
check EGR. See TEST HE: EGR SYSTEM , step 100) under SYSTEM TESTS in SELF-
DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article. If LONGFT1 or LONGFT2 PID value is
low (-20 percent), concentrate checks in areas that would cause engine to run rich. If LONGFT1 or
LONGFT2 PID value is high (+20 percent), concentrate checks in areas that would cause engine to run
lean. If VPWR PID voltage is not 10.5-17.0 volts, check charging system. See appropriate
GENERATORS & REGULATORS article in ELECTRICAL. If VPWR PID voltage is 10.5-17.0 volts
but not within .5 volt of battery voltage, check battery supply to PCM power relay. Check VPWR circuit
between PCM and PCM power relay, and PWR GND circuits to PCM. See ENGINE PERFORMANCE

NOTE:

If the following tests fail to correct spark knock concern, it is recommended that
owner changes source of fuel. Ensure proper grade of CNG fuel is being used.

NOTE:

Fuel consumption can be increased during stop-and-go driving, trailer towing,
short-run operation, extended winter warm-up periods, improper tire inflation,
high speed driving, improper axle ratio and aftermarket add-ons. Determine if
these factors are the cause of poor fuel mileage before proceeding with
diagnostic procedure.

2003 Ford Pickup F150

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

in SYSTEM WIRING DIAGRAMS article in ELECTRICAL.

Check A/T Torque Converter Clutch (TCC) and/or TCC solenoid for proper operation. See appropriate
DIAGNOSIS article in AUTOMATIC TRANSMISSIONS.

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

Check for correct PCM Vehicle Identification (VID) block information. See FLASH ELECTRICALLY
ERASEABLE PROGRAMMABLE READ ONLY MEMORY (FLASH EEPROM) under
PROGRAMMING PCM in SELF-DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article. Check
for dragging brakes and repair as necessary. See appropriate DISC & DRUM article in BRAKES.
Visually inspect Mass Air Flow (MAF) sensor for contamination.

Check cooling system for overheating. If cooling system is overheating, repair as necessary. See
appropriate ELECTRIC COOLING FANS article in ENGINE COOLING.

Check transmission fluid level. Repair as necessary.

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

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

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

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

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

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.

VEHICLE FAILS EMISSIONS/EMISSIONS COMPLIANCE

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

Check emission related systems. See TEST HX: EVAPORATIVE EMISSION MONITOR &
SYSTEM under SYSTEM TESTS in SELF-DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE
article, or VEHICLE FAILS EMISSIONS/EMISSIONS COMPLIANCE under SYMPTOMS in
TROUBLE SHOOTING - NO CODES - CNG, FLEX-FUEL & GASOLINE article.

ALTERNATE FUEL SWITCH/INDICATOR OPERATION

Check alternate fuel switch/indicator. See TEST NB: ALT FUEL INDICATOR under SYSTEM
TESTS in SELF-DIAGNOSTICS - BI-FUEL - GASOLINE/CNG article.

INTERMITTENTS

2003 Ford Pickup F150

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

INTERMITTENT PROBLEM DIAGNOSIS

Intermittent diagnostic techniques help find and isolate root causes of intermittent faults associated with EEC
system. The material is organized to help find fault and perform repair. The process of finding and isolating an
intermittent fault, starts with recreating fault symptom, accumulating and comparing data to typical values and
analyzing the results. Before proceeding, ensure the following:

Customary mechanical system tests and inspections DO NOT reveal a problem. Mechanical component
problems can make an alternative fuel system react abnormally.

Technical Service Bulletins (TSBs) have been reviewed.

QUICK TEST and associated SYSTEM TESTS have been completed without finding a fault, and
symptom is still occurring.

TEST PROCEDURES

Recreating Fault

Recreating fault is the first step in isolating cause of an intermittent symptom. Conditions to recreate fault are:
engine temperature, ambient temperature, engine RPM, moisture conditions, engine load, engine idle,
acceleration, deceleration and road conditions (smooth or bumpy).

Accumulating Alternative Fuel Data

Alternative Fuel data can be accumulated in a number of ways. Gather as much data as possible when fault is
occurring to prevent misdiagnosis. Data should be accumulated during different operating conditions, and based
on customer description of intermittent fault. This will require recording Parameter Identification (PID) data in
4 conditions for comparison: KOEO, HOT IDLE, 30 MPH and 55 MPH. See appropriate PIN VOLTAGE/PID
VALUE CHARTS article.

Selecting & Viewing PIDs

Turn ignition off. Ensure test equipment is properly attached. Program scan tool using the following steps:

Turn ignition on or start engine and allow to idle.

Select VEHICLE & ENGINE SELECTION menu.

Select NEW VEHICLE, YEAR & MODEL.

Select DIAGNOSTIC DATA LINK.

Select AFCM-ALTERNATE FUEL CTRL MODULE (AFCM supports similar DTCs and PIDs as PCM,
but may have an entirely different meaning).

Select PID/DATA MONITOR AND RECORD.

Select PIDs and press trigger on NGS tester.

Press START to begin monitoring. If PID value is not as specified, perform appropriate SYSTEM TEST.

NOTE:

Always view PCM PIDs before AFCM PIDs.

2003 Ford Pickup F150

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

See SYSTEM TESTS in SELF-DIAGNOSTICS - BI-FUEL - GASOLINE/CNG article.

Peripheral Inputs

Some signals may require certain peripherals or auxiliary tools to aid in diagnostics. In some cases, these
devices can be inserted into the measurement jacks of the scan tool or DVOM. Scan tool is capable of recording
value from measurement jacks on scan tool while storing value from other PIDs. For example, connecting an
electronic fuel pressure gauge to monitor and record fuel pressure voltage reading, and capturing data, would
help find the fault.

Analyzing Alternative Fuel Data

Once fault area is identified, circuit(s) must be checked to determine if wiring or component is at fault. When
making circuit and component measurements, ensure all accessories, dome, trunk and hood lights are off. Use
the following methods to diagnose a suspected alternative fuel wire circuit or device. Some methods are specific
to a certain type of alternative fuel device. Such as; coil resistance (solenoids and relays) or harness opens or
shorts.

Change Input & Verify Output Response

The purpose is to verify how AFCM circuits respond to a sensor input. Access AFCM, select, monitor and
record appropriate sensor PID(s). Create a condition to cause an input condition to change and observe PID or
actuator signal circuit change, with use of a scan tool.

2003 Ford Pickup F150

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

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