Ford F150 Pickup. Instruction — part 1606

z

Check transmission fluid level. Repair as necessary.

z

Check secondary ignition system. See TEST JB: SECONDARY IGNITION under SYSTEM TESTS in
SELF-DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE 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 fuel delivery system. See TEST HC: FUEL DELIVERY SYSTEM under SYSTEM TESTS in
SELF-DIAGNOSTICS - BI-FUEL - GASOLINE/LPG 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.

z

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 - GASOLINE & CNG, FLEX-FUEL & GASOLINE article.

VEHICLE FAILS EMISSIONS/EMISSIONS COMPLIANCE

z

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

z

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.

INTERMITTENTS

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:

z

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

z

Technical Service Bulletins (TSBs) have been reviewed.

z

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

TEST PROCEDURES

Recreating Fault

2003 Ford Pickup F150

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

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 PIN VOLTAGE CHARTS -
GASOLINE/LPG article.

Selecting & Viewing PIDs

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

z

Turn ignition on or start engine and allow to idle.

z

Select VEHICLE & ENGINE SELECTION menu.

z

Select NEW VEHICLE, YEAR & MODEL.

z

Select DIAGNOSTIC DATA LINK.

z

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

z

Select PID/DATA MONITOR AND RECORD.

z

Select PIDs and press trigger on NGS tester.

z

Press START to begin monitoring. If PID value is not as specified, perform appropriate SYSTEM TEST.
See SYSTEM TESTS in SELF-DIAGNOSTICS - BI-FUEL - GASOLINE/LPG 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.

NOTE:

Always view PCM PIDs before AFCM PIDs.

2003 Ford Pickup F150

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

Change Input and Verify Output Response

The purpose is to verify how compuvalve and actuator circuit 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/LPG

2003 ENGINE PERFORMANCE

Trouble Shooting - No Codes - CNG, Flex-Fuel & Gasoline

INTRODUCTION

Before proceeding with diagnostics, check for applicable Technical Service Bulletins (TSBs). If there are no
applicable TSBs, perform QUICK TEST in SELF-DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE
article. Use this article to diagnose driveability problems existing when a Diagnostic Trouble Code (DTC) is not
present.

Symptom checks can direct the technician to malfunctioning component(s) for further diagnosis. A symptom
should lead to a specific component or system test and/or adjustment.

SYMPTOMS

SYMPTOM DIAGNOSIS

Symptom checks cannot be used properly unless problem occurs while vehicle is being tested. To reduce
diagnostic time, ensure steps in BASIC DIAGNOSTIC PROCEDURES - TRUCKS - EXCEPT DIESEL
article and SELF-DIAGNOSTICS - CNG, FLEX-FUEL & GASOLINE article were performed before
diagnosing a symptom. Symptom checks are listed in order of probability, ease of accomplishment, and
accessibility. Symptoms available for diagnosis are as follows:

z

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

z

HARD START/LONG CRANK OR ERRATIC START/CRANK

z

NO START/NORMAL CRANK

z

SLOW RETURN TO IDLE

z

FAST IDLE OR DIESELS/RUNS ON

z

LOW IDLE (STALLS ON DECELERATION)

z

BACKFIRES

NOTE:

This article covers gasoline, flex-fuel and CNG vehicles only. For Bi-Fuel
(gasoline/LPG or gasoline/CNG) vehicles, go to appropriate TROUBLE
SHOOTING - NO CODES - BI-FUEL article.

NOTE:

For specifications, see appropriate ON-VEHICLE ADJUSTMENTS or SERVICE &
ADJUSTMENT SPECIFICATIONS article.

CAUTION: When battery is disconnected, vehicle computer and memory systems

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 - CNG, Flex-Fuel & Gasoline

2003 Ford Pickup F150

2003 ENGINE PERFORMANCE Trouble Shooting - No Codes - CNG, Flex-Fuel & Gasoline