Fuel Pump Relay - Component Location Correction

89Ford10

FUEL SYSTEM - FUEL PUMP RELAY - ELECTRICAL VACUUM TROUBLESHOOTING MANUAL (EVTM) CORRECTION

Article No. 89-5A-10

FORD: 1988 TEMPO

LINCOLN-MERCURY: 1988 TOPAZ


ISSUE: The component location given for the Fuel Pump Relay in the Component Location listing for the Electronic Engine Control Section, page 43 of the 1988 Tempo/Topaz EVTM is incorrect.

ACTION: The location should read: Behind LH side of I/P, as shown on this TSB. This information should be inserted into your 1988 Tempo/Topaz EVTM.


OTHER APPLICABLE ARTICLES: None
WARRANTY STATUS: "INFORMATION ONLY"
OASIS CODES: 2800

1988 ELECTRONIC ENGINE CONTROL 43

HOW THE CIRCUIT WORKS

The Electronic Engine Control (EEC) System includes an Electronic Control Assembly (ECA) that receives inputs from various sensors. The ECA uses this information to control (1) Fuel Flow, (2) Exhaust Gas Recirculation (EGR), (3) Ignition and (4) Evaporative Emissions. These four systems and the ECA work together to provide improved fuel economy and performance, and lower exhaust emissions.

EEC Power Relay

The EEC Power Relay supplies power to the ECA and ECA System related components. When the Ignition Switch is turned to RUN or START, voltage is applied to the EEC Power Relay coil, and the relay's contacts close.

Fuse Link J applies voltage to the Fuel Pump Relay. It also applies voltage to the Fuel injectors, the ECA, and the EGR Solenoid through the EEC Power Relay contacts.

Fuel Flow

The 2.3L engine is equipped with Electronic Fuel Injection (EFI), which injects fuel into the engine through the Fuel Injectors located above each intake valve.

The duration and timing of the Fuel Injectors are controlled by the ECA. The ECA determines when to operate the Fuel Injectors according to the input it receives from various sensors.

The Electric Fuel Pump supplies fuel under pressure to the Fuel Injectors. When the Ignition Switch is in RUN or START, voltage is applied to the Fuel Pump Relay coil. The coil is grounded by the ECA and the relay contacts close. Voltage is now applied to the Electric Fuel Pump.

The Inertia Switch is a safety device which cuts off voltage to the Electric Fuel Pump in the event of a collision. Once the Inertia Switch opens it must be reset manually.

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COMPONENT LOCATION Figure

Inertia Switch . . . . . . . . . On LH hinge support, in luggage compartment. . . . . . . . . . . . . 48-3
Air Charge Temperature Sensor . . RH side of engine, in intake manifold. . . . . . . . . . . . . . . . 49-1
Canister Purge Solenoid . . . . . LH side of engine, top of transaxle. . . . . . . . . . . . . . . . . 45-1
Diode . . . . . . . . . . . . . . Taped in fuel charge harness, in T/O to idle control solenoid. *
EEC Power Relay . . . . . . . . . Behind RH side of I/P. . . . . . . . . . . . . . . . . . . . . . . . 46-1
EGR Vacuum Regulator (EVR) . . . Mounted on LH strut tower. . . . . . . . . . . . . . . . . . . . . . 48-1
EGR Valve Position Sensor . . . . Center front of dash . . . . . . . . . . . . . . . . . . . . . . . 47-1
Electric Fuel Pump . . . . . . . Top of fuel tank . . . . . . . . . . . . . . . . . . . . . . . . . 49-2
Electronic Control Assembly (ECA)

. . . . . . . . . . . . . . . . Behind LH side of I/P. . . . . . . . . . . . . . . . . . . . . . . 46-1 Engine Coolant Temperature
Sensor . . . . . . . . . . . . LH side of engine, near top. . . . . . . . . . . . . . . . . . . . 45-1
Fuel Injectors . . . . . . . . . Top of each cylinder . . . . . . . . . . . . . . . . . . . . . . . *
Fuel Pump Relay . . . . . . . . . Behind LH side of I/P . . . . . . . . . . . . . . . . . . . . . . 132-1
Fuse Link G . . . . . . . . . . . Front of LH strut tower, near T/O to C410 . . . . . . . . . . . . 48-1
Fuse Link J . . . . . . . . . . . Near starter relay. . . . . . . . . . . . . . . . . . . . . . . . 48-1
Heated Exhaust Gas Oxygen
Sensor (HEGO) . . . . . . . . . Rear of engine, on exhaust manifold . . . . . . . . . . . . . . . 49-1
Idle Control Solenoid . . . . . . Top LH side of engine . . . . . . . . . . . . . . . . . . . . . . 49-1
Ignition Suppressor Resistor. . . In engine harness, LH rear of engine compartment . . . . . . . . 47-1
Ignition Switch . . . . . . . . . Top RH side of steering column . . . . . . . . . . . . . . . . . * Manifold Absolute Pressure
Sensor . . . . . . . . . . . . On RH strut tower . . . . . . . . . . . . . . . . . . . . . . . . 47-1
Power Steering Pressure Switch . Top RH side of engine, in power steering hose . . . . . . . . . . 47-1
Speed Sensor . . . . . . . . . . LH rear side of transmission . . . . . . . . . . . . . . . . . . 45-1
Starter Diode . . . . . . . . . . Taped to harness, in front of LH strut tower . . . . . . . . . . *
Throttle Position Sensor . . . . Top LH side of engine . . . . . . . . . . . . . . . . . . . . . . 49-1
VIP Self-Test Connector . . . . . RH side of dash . . . . . . . . . . . . . . . . . . . . . . . . . 47-1
VIP Self-Test Connector C251. . . RH side of dash . . . . . . . . . . . . . . . . . . . . . . . . . 47-1

* No Figure Available


Refer to Location Index page 133 for Connector, Splice and Ground Descriptions and Locations.

44 ELECTRONIC ENGINE CONTROL 1988
Exhaust Gas Recirculation (EGR)

The ECA controls exhaust gas recirculation by varying the voltage applied to the EGR Valve Position Sensor. This valve regulates the amount of vacuum applied to the EGR valve. The EGR Valve Position Sensor indicates valve position to the ECA by providing a voltage signal proportional to the EGR position. The ECA determines correct EGR position depending on engine operating conditions.

Canister Purge

The carbon canister collects fuel vapors from the fuel tank and other components to be burned later in the engine. The Canister Purge Solenoid is controlled by the ECA. When the ECA grounds the Canister Purge Solenoid the vapors are released to the engine for burning.

Idle Control Solenoid

The Idle Control Solenoid controls engine idle speed by regulating the amount of air allowed to pass around the throttle plates. This permits the ECA to make idle speed corrections to prevent engine stall during cold engine warmups and as engine load changes. The Diode provides voltage spike suppression.

Ignition

The EEC System has a special Distributor and Ignition Module. The EEC Distributor has no vacuum advance mechanism. Instead, all ignition timing is controlled by the ECA.

The ECA receives engine timing information from the Distributor through the TFI Ignition Module. The ECA uses this information to determine spark timing and advance.

Electronic Control Assembly Inputs

The ECA uses information from various sensors to determine engine operating conditions.

Air Charge Temperature Sensor

The Air Charge Temperature Sensor is a thermistor in which resistance decreases as manifold air temperature increases (Negative Temperature Co-efficient or NTC).

The ECA detects the voltage drop across the Air Charge Temperature Sensor and uses this information to help calculate fuel delivery.

Throttle Position Sensor

The Throttle Position Sensor is a potentiometer. The sensor output is a DC voltage that varies with throttle plate angle. By monitoring the Throttle Position Sensor output, the ECA calculates fuel delivery requirements based on driver demand.

Engine Coolant Temperature Sensor

The Engine Coolant Temperature Sensor is a thermistor in which resistance decreases as engine coolant temperature decreases. The ECA detects the voltage drop across the Engine Coolant Temperature Sensor and uses this information to help calculate fuel delivery, spark timing and EGR control.

Manifold Absolute Pressure (MAP) Sensor

The Manifold Absolute Pressure (MAP) Sensor measures the pressure in the intake manifold and provides this information as a variable frequency signal to the ECA. With the Ignition Switch in the Key-On/EngineOff position, the MAP Sensor measures the barometric pressure in the intake manifold. With the Ignition Switch in the Key-On/Engine-Running position, the MAP Sensor measures the varying pressure (vacuum) in the intake manifold.

Heated Exhaust Gas Oxygen (HEGO) Sensor

The Heated Exhaust Gas Oxygen (HEGO) Sensor provides a voltage to the ECA for regulating the air/fuel ratio by sensing the oxygen content of the exhaust gases. Oxygen shows a lean exhaust gas mixture while no oxygen shows a rich mixture.


For further diagnostic information refer to the Engine/Emissions Diagnosis Manual (Volume H).