Fuel Control

1994 PCED OBDI-A

SECTION 6A: EEC-IV Pinpoint Test
Procedures

H: Fuel Control
Introduction

Note

You should enter this Pinpoint Test only when you have been directed here from Diagnostic Routines, Section 2A, or Pinpoint Test S.

Remember

To prevent the replacement of good components, be aware that the following non-EEC areas may be at fault:

Ignition System
Evaporative Emission (EVAP) System
Positive Crankcase Ventilation System
Secondary Air Injection System
Exhaust Gas Recirculation System
Air Intake System/Filter
Fuel and Engine Oil Contamination
Electrical System
Fuel System (i.e. Fuel Filter Pump Pressure)
Intake Manifold, Supercharger, Charge Air Cooler Leaks
Exhaust Manifold System Leak/Plugged
Engine Cooling System
Base Engine (i.e. cam timing, compression)

This Pinpoint Test is intended to diagnose only the following:

HO2S/Heater
HO2S Connection
Vacuum Systems
Fuel Injector
Powertrain Control Module (PCM)
Harness Circuits: HO2S GND, HO2S, INJ. 1-8, VPWR and SIG RTN

Description

The Heated Oxygen Sensor (HO2S) reacts with the oxygen in the exhaust gases and generates a voltage based on this reaction. A low voltage indicates too much oxygen or a lean condition. A high voltage indicates not enough oxygen or a rich condition. The fuel injector is a typical on/off device. The amount of fuel delivered is determined by how long the injector is held open.

Pinpoint Test Schematics

SFI: 1.9L Escort/Tracer

SFI: 2.0L Probe (M5, 49 States)

SFI: 2.0L Probe (California, M/T and CD4E)

SFI: 2.3L HSC Tempo/Topaz

SFI: 3.0L and 3.2L Taurus SHO

3.2L Taurus SHO

SFI: 3.0L Taurus/Sable and Aerostar and 3.8L Taurus/Sable, Thunderbird/Cougar, Continental

Test Pin 44 — HO2S
Application	Wire Color
Taurus/Sable	DB/LG
All Others	GY/LB

Test Pin 43 — HO2S
Application	Wire Color
All Others	R/BK

Aerostar

SFI: 4.6L Crown Victoria/Grand Marquis, Mark VIII, Town Car

Test Pin 44—HO2S
Application	Wire Color
4.6L	GY/LB

Test Pin 43—HO2S
Application	Wire Color
4.6L	R/BK

SFI: 5.0L Mustang

Test Pin 29—HO2S
Application	Wire Color
Mustang	GY/LB

Test Pin 43—HO2S
Application	Wire Color
Mustang	R/BK

MFI: 2.3L OHC Ranger

SFI: 2.3L OHC Ranger (Calif. Only)

MFI: 4.0L Aerostar

SFI: 3.0L Aerostar and Ranger/4.0L Explorer/4.0L Ranger (Calif. Only)

MFI: 4.0L Ranger (49 State)

MFI: 4.9L E/F Series and Bronco

SFI: 5.0L F Series and Bronco

MFI: 5.0L, 5.8L and 7.5L E/F Series and Bronco

MFI: 7.0L F-Series

WARNING: THE FUEL SYSTEM WILL REMAIN PRESSURIZED WHEN THE ENGINE IS NOT RUNNING. TO PREVENT INJURY OR FIRE USE CAUTION WHEN WORKING ON THE FUEL SYSTEM.

FUEL PRESSURE SPECIFICATION TABLES

Car Engines
ENGINE MODE	ENGINE APPLICATION			All Other Applications
ENGINE MODE	2.3L HSC MFI	3.0L SHO SFI	3.8L SC SFI	All Other Applications
ENGINE RUNNING	45-60 PSI 310-415 kPa	28-33 PSI 193-227 kPa	30-40 PSI 210-280 kPa	30-45 PSI 210-310 kPa
KEY ON ENGINE OFF	50-60 PSI 345-415 kPa	30-45 PSI 210-310 kPa	35-40 PSI 240-280 kPa	35-40 PSI 240-280 kPa

Truck Engines
ENGINE MODE	ENGINE APPLICATION
ENGINE MODE	4.9L MFI	All Other Applications
ENGINE RUNNING	45-60 PSI 310-415 kPa	30-45 PSI 210-310 kPa
KEY ON ENGINE OFF	50-60 PSI 345-415 kPa	35-45 PSI 240-310 kPa

Note: Maximum fuel pressure is obtainable at WOT or the vacuum hose removed from the fuel pressure regulator.

Injector Bank Resistance
Specification Table 1 (Not For SFI)

All Engines
Values Are In Ohms
2.3L	3.0L 4.0L/4.9L	5.0L/5.8L 7.0L/7.5L
6.0 - 8.5	4.0 - 5.5	3.0 - 4.0

Single Injector Resistance
Specification Table 2

All Engines
Values Are In Ohms
ALL ENGINES
11.0 - 18.0

H: Pinpoint Tests