Fuel Pressure Specifications Revised - Manual Update (94-24B-1)

Publication date: 1994-12-01
Reference number: 94-24B-1

FUEL PRESSURE SPECIFICATIONS REVISED - MANUAL UPDATE

TECHNICAL SERVICE BULLETIN

Reference Number(s): 94-24B-1, Date of Issue: December, 1994

FUEL DELIVERY SYSTEMS

APPLICATION

Model: 1994 Ford Crown Victoria, Tempo

1994-95 Ford Escort, Mustang, Probe, Taurus, Thunderbird

1995 Ford Contour

1994 Lincoln-Mercury Continental, Grand Marquis, Topaz, Town Car

1994-95 Lincoln-Mercury Cougar, Mark VIII, Sable, Tracer

1995 Lincoln-Mercury Mystique

1994 Ford Ranger

1994-95 Ford Aeorstar, Bronco, Econoline, Explorer, F-150-350 Series

Bulletin No.: 94-24B-1

Date: December, 1994

REFERENCE:

Powertrain Control/Emissions/Diagnosis Manual (OBD I), 1994 - Pages 9A-23 and 9A-28 - Fuel Delivery Systems - Fuel Pressure Specifications and Diagnostics Revised Powertrain Control/Emissions Diagnosis Manual (OBD I), 1995 - PAGE 9A-24 - Fuel Delivery Systems - Fuel Pressure Specifications Revised

ISSUE

Some fuel pressure specifications and diagnostics are incorrect as shown and require revision. 1994 and 1995 PC/ED Manuals (OBD I) are affected on the pages indicated:

1994: Pages 9A-23 and 9A-28

1995: Page 9A-24

ACTION

Refer to the pages following this QSB article for the revised information.

FUEL DELIVERY SYSTEMS

CAR ENGINES FUEL PRESSURE SPECIFICATIONS INFORMATION

Engine Mode	Engine Application 2.3L HSC SFI	Engine Application 3.0L SHO SFI	Engine Application 3.8L SC SFI	Engine Application All Other Applications
Engine Running	45-60 PSI 310-415 kPa	28-33 PSI 193-227 kPa	28-54 PSI 193-372 kPa	35-45 PSI 240-310 kPa
Key On Engine Off	50-60 PSI 345-415 kPa	30-45 PSI 210-310 kPa	35-45 PSI 240-310 kPa	35-45 PSI 240-310 kPa

TRUCK ENGINES FUEL PRESSURE SPECIFICATIONS INFORMATION

Engine Mode	Engine Application 4.9L MFI	Engine Application All Other Applications
Engine Running	45-60 PSI 310-415 kPa	28-45 PSI 193-310 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.

If fuel lines/systems have been drained or evacuated, it may take up to 15 seconds to obtain the pressure specified.

SYSTEM DIAGNOSIS

NOTE: Grounding the FP lead at the DLC will allow the pump to run continuously with the ignition switch on. See Fig 1 .

Fig 1: Data Link Connector (DLC)

Fig 2: SYSTEM DIAGNOSIS INFORMATION TABLE 1

Fig 3: SYSTEM DIAGNOSIS INFORMATION TABLE 2

Fig 4: SYSTEM DIAGNOSIS INFORMATION TABLE 3

Fig 5: SYSTEM DIAGNOSIS INFORMATION TABLE 4

FUEL PUMP CIRCUIT OPERATION

When the ignition is switched to the ON position, it turns the EEC Power Relay on. The EEC Power Relay provides power to the EEC-IV processor and the control side of the fuel pump relay. Power for the fuel pump is supplied through a fuse link or high current fuse attached to the starter solenoid (battery side). From the fuse link or high current fuse, current flow is through the fuel pump relay and Inertia Fuel Shutoff (IFS) switch to the fuel pump. The IFS switch is a safety device used to shut off the fuel pump in the event of a collision. If the IFS switch is "tripped," it must be reset by depressing the white or red button on the top of the switch. The fuel pump relay is controlled by the Powertrain Control Module (PCM).

When the ignition switch is turned to the ON position, the fuel pump will operate. If the ignition switch is not turned to the START position, the PCM will shut the fuel pump off after approximately one second. The PCM will operate the fuel pump when the ignition is in the START position to provide fuel while cranking.

After the engine starts, the PCM will continue to operate the fuel pump unless the engine stops, engine speed drops below 120 rpm, or the IFS switch is "tripped."

FUEL SYSTEM DESCRIPTION FOR TAURUS FLEX FUEL & 4.6L-4V MARK VIII

The Taurus Flex Fuel and Mark VIII have a DUAL FUEL PUMP VOLTAGE system (Figures 11 and 12 ) to aid in fuel system noise concerns. The fuel pump operates in the high voltage mode (12-14 volts) during crank (for 5 to 60 seconds depending upon engine temperature), after start-up, at engine speeds in excess of 3300 rpm, and during periods of Wide Open Throttle when maximum fuel delivery may be required. The normal operating mode calls for low voltage (7-10 volts) to the fuel pump. This minimizes operating noise. Fuel pump operation is controlled by the PCM. The fuel pump operates in the same manner as all other systems except for the two speed feature. For diagnosing fuel pump noise in the Taurus Flex Fuel, GO to FDS16.

CAR ENGINES FUEL PRESSURE SPECIFICATIONS INFORMATION

Engine Mode	Engine Application 3.0L SHO SFI	Engine Application 3.8L SC SFI	Engine Application All Other Applications
Engine Running	28-33 PSI 193-227 kPa	28-54 PSI 193-372 kPa	35-45 PSI 240-310 kPa
Key On Engine Off	30-45 PSI 210-310 kPa	35-45 PSI 240-310 kPa	35-45 PSI 240-310 kPa

TRUCK ENGINES FUEL PRESSURE SPECIFICATIONS INFORMATION

Engine Mode	Engine Application 4.9L MFI	Engine Application All Other Applications
Engine Running	45-60 PSI 310-415 kPa	28-45 PSI 193-310 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.

If fuel lines/systems have been drained or evacuated, it may take up to 15 seconds to obtain the pressure specified.

WARRANTY STATUS

Information only.

OASIS CODE

690000.

Fuel Pressure Specifications Revised - Manual Update (94-24B-1)