Fuel Injection System - Cfi Lincoln Continental VII

COMPONENT TESTING

Note. Specific component testing information not available. Refer to any tests performed during REMOVAL & INSTALLATION or OVERHAUL procedures

DESCRIPTION

The Ford Central Fuel Injection System (CFI) is used on 3.8L and 5.0L engines. It is a single point, pulse time modulated injection system. Fuel is metered into the air intake stream according to engine demands by 2 solenoid injection valves, mounted in a throttle body on the intake manifold.

The system basically consists of 4 sub-assemblies: fuel delivery, air induction, engine sensors and the Electronic Control Assembly (ECA) of the Electronic Engine Control (EEC-IV) system. The fuel delivery system includes a high pressure fuel pump, a primary fuel filter, a secondary fuel filter, fuel supply and return lines, fuel injectors and fuel pressure regulator.

The air induction system includes the throttle body, intake manifold, Cold Engine Speed Control (5.0L only), and Idle Speed Control motor (3.8L only).

Engine sensors are as follows: Throttle Position Sensor (TPS), Manifold Absolute Pressure (MAP) sensor, Engine Coolant Temperature (ECT) sensor, Air Charge Temperature (ACT) sensor, EGR Valve Position (EVP) sensor, Exhaust Gas Oxygen (EGO) sensor, and Profile Ignition Pick-Up (PIP).

Ford EEC-IV/CFI System Components Illustration applies to V8 only; V6 is similar. Scheme 1

Fuel Pump

The Crown Victoria, Grand Marquis, and Town Car models use a high pressure electric fuel pump located inside the fuel tank. The pump receives power through starter relay, fuel pump relay, and EEC power relay. Fuel pump incorporates an internal relief valve.

The fuel pump relay is located on the left center fender apron on the Crown Victoria and Grand Marquis models. On the Town Car, relay is located on the right rear fender apron.

When ignition switch is in the "ON" position, the EEC power relay is activated. Power is provided to fuel pump relay and to a timer within the ECA. The fuel pump runs at a reduced voltage through a resistance wire and pump relay.

If the ignition switch is not turned to the "START" position within 1 second, the ECA timing device will deactivate the fuel pump relay which in turn de-energizes the fuel pump. This circuitry provides pre-pressurization of the fuel system.

When the ignition switch is turned to the "START" position, the starter relay provides power to the fuel pump, by-passing the fuel pump relay. Full system voltage is provided to fuel pump during cranking modes.

With ignition switch in the "ON" position and the engine running, power to fuel pump is again supplied through fuel pump relay and resistance wire. The ECA senses engine RPM and deactivates the fuel pump relay when engine stops or engine speed falls below 120 RPM.

All models except Crown Victoria, Grand Marquis, and Town Car use a low pressure in-tank electric fuel pump and an externally mounted high pressure in-line electric fuel pump. The high pressure pump is located on the right frame rail under the rear seat. The low pressure fuel pump provides pressurized fuel to the inlet side of the high pressure pump. The low pressure pump operates on 11V.

The dual fuel pump electrical circuit is similar to the single pump circuit except during cranking mode. Fuel pump relay is activated through the ECA and full battery voltage is not supplied to the fuel pump.

Fuel pump relay is located under driver's seat on Mustang/Capri models. On Thunderbird/Cougar models it is located above right rear wheel well.

Fuel Pressure Regulator

The fuel pressure regulator controls fuel pressure to 39 psi (2.74 kg/cm 2 ) across the fuel injectors. Excess fuel is returned to the tank through a return line. The pressure regulator is mounted on the charging main body so as to nullify the effects of the supply line pressure drops. It is not sensitive to back pressure in the return line to the tank.

The pressure regulator also maintains fuel supply pressure upon engine and fuel pump shut down. Maintaining fuel pressure prevents fuel line vapor formation which allows for rapid restarts and stable idle operation.

Fuel Injectors

The fuel injector valve bodies consist of solenoid actuated pintle and needle valve assembly. Since injector orifice is fixed and fuel pressure is constant, fuel flow is controlled by injector "ON" time. Injectors are actuated by the ECA at twice the crankshaft speed.

Cutaway View of Injector Valve. Scheme 2

Inertia Switch

The inertia switch is designed to open the fuel pump power circuit in the event of a collision. It is reset by pushing a button on switch assembly. The switch should not be reset until fuel system has been inspected for damage or leaks.

Inertia Switch Location Applies to all models except Mustang/Capri 3-door sedans (switch located in spare tire well). Scheme 3

Fuel Charging Operation. Scheme 4

AIR INDUCTION

Air enters the engine through the throttle body at a rate controlled by the throttle valves, which are connected to the accelerator linkage.

Cold Engine Speed Control (5.0L Only)

Fast idle speed position of the throttle valves is controlled by a fast idle cam connected to and positioned by a bimetal spring and electric positive heating element. A voltage of 7.3V is supplied to the heating element from the alternator stator only when the engine is running.

As bimetal is heated by electric heating element during engine warm-up, fast idle is reduced to curb idle. A vacuum actuated automatic kickdown motor is also used. Vacuum signal is controlled by the ECA.

Idle Speed Control (ISC) Motor (3.8L Only)

The ISC motor, mounted on the throttle body assembly, controls idle speed during both cold and warm engine operation. ISC motor is controlled by the ECA.

An Idle Tracking Switch (ITS), integral with the ISC motor, is used to signal the ECA when the throttle lever has contacted the motor actuator. The ECA will in turn begin idle control.

Throttle Position Sensor (TPS)

The TPS is mounted on the throttle body and is directly connected to throttle shaft. The TPS senses throttle movement and position and transmits appropriate electrical signal to ECA. These signals are used by the ECA to determine proper air/fuel mixture, spark and EGR operation. TPS is NOT adjustable.

Manifold Absolute Pressure (MAP) Sensors

The MAP sensor assembly is located on the right fender apron (5.0L models, left fender apron on 3.8L models) in the engine compartment. The MAP sensor monitors and signals ECA of changes in intake manifold pressure which result from engine load, speed, and atmospheric pressure changes.

Engine Coolant Temperature (ECT) Sensor

The ECT, threaded into intake manifold water jacket directly above water pump by-pass hose, monitors and signals ECA of water temperature. The ECA uses these signals for mixture enrichment during cold operation, ignition timing, and EGR operation.

Air Charge Temperature (ACT) Sensor

The ACT monitors and signals ECA of air/fuel charge temperatures. It is either threaded into intake manifold air runner below accelerator linkage or mounted on air cleaner. ACT sensor input is used by ECA as density corrector for air flow calculations and to proportion the cold enrichment fuel flow.

EGR Valve Position (EVP) Sensor

The EVP, mounted on the EGR valve, signals ECA of EGR valve opening so ECA can subtract EGR flow from total flow into manifold. This excludes EGR flow from being computed into mixture requirements.

Exhaust Gas Oxygen (EGO) Sensor

The EGO monitors oxygen content of exhaust gases and sends a constantly changing voltage signal to ECA. The ECA analyzes signal and changes air/fuel mixture accordingly.

Profile Ignition Pick-Up (PIP)

Located in the distributor, a "Hall Effect" Vane Switch sensor furnishes crankshaft position information to the ECA.

ELECTRONIC CONTROL ASSEMBLY (ECA)

The ECA is a solid state micro-computer consisting of a processor assembly and a calibration assembly. The ECA is located in the passenger compartment under the instrument panel except for Mustang/Capri where it is under the passenger seat. The ECA is the "brain" of the EEC-IV/CFI system.

Processor Assembly

The processor contains circuits designed to continuously sample input signals from sensors, calculate and send out proper control signals to adjust air/fuel ratio, spark timing and emission system operation. The processor also provides a continuous operating reference voltage of 5 volts between the ECA and its sensors.

Calibration Assembly

The calibration assembly contains the "memory" and programming used to provide the processor assembly with operating information for a particular vehicle. It recalls information from its memory when required.

Note. Different calibration information is used in different vehicle applications, such as Federal and California.

TESTING & DIAGNOSIS

Note. Due to the complexity of the EEC-IV system, full testing cannot be done unless a special tester is used. Instructions for testing come with the tester, which is available from Owatonna Tool Co. However, some checks can be made using standard shop equipment. These checks are outlined in the following procedures

1. No repairs or adjustments can be made to the ECA. If diagnosis shows ECA is not functioning properly, it must be replaced.
2. Shorting the wiring harness across a solenoid valve can burn out circuitry in the ECA that controls the solenoid valve actuator.
3. The EEC-IV system contains transistors which CANNOT tolerate excessive voltage surges or transient voltage. Never try to jump-start the vehicle with 24 volts.
4. Fuel supply lines will remain pressurized for long periods of time after key is turned off. This pressure must be relieved before servicing fuel system. Removing air cleaner and cautiously depress pin in Schrader valve on fuel charging main body. This will expel fuel into throttle body.

PRELIMINARY CHECKS

1. Perform basic ignition system and fuel system checks to ensure there is fuel and spark.
2. Remove air cleaner assembly and inspect all vacuum and pressure hoses for proper connection to fittings, or any broken, cracked or pinched conditions.
3. Inspect CFI sub-system wiring harnesses for proper connections to the EGR solenoid valves. Red wire to both, Yellow wire to EGR control solenoid, and Dark Green wire to EGR vent solenoid.
4. Check for loose or detached connectors, broken or detached wires. Ensure all terminals are seated firmly and are not corroded. Check for partially broken or frayed wires or any shorting between wires.
5. Inspect sensors for physical damage. Inspect vehicle electrical system. Check battery for full charge and battery cable connections for tightness.
6. Inside passenger compartment, check to make sure the ECA power relay is securely attached and has a good ground connection.

Electrical Continuity (Crown Victoria, Grand Marquis & Town Car)

1. Unplug electrical connector just forward of fuel tank. Connect voltmeter to body wiring harness connector. Turn ignition switch "ON" while watching voltmeter.
2. Voltage should rise to battery voltage, then return to zero volts after about 1 second. Momentarily turn key to "START" position. Voltage should rise to about 8 volts while cranking. If voltage is not as specified, check electrical system. (Scheme 5)

Fuel Pump Wiring Diagram Crown Victoria, Grand Marquis & Town Car only. Scheme 5

Electrical Continuity (All Others)

1. Unplug electrical connector to fuel pumps at high pressure fuel pump. Connect voltmeter to body wiring harness connector. Turn ignition switch "ON" while watching voltmeter.
2. Voltage should rise to battery voltage, then return to zero volts after about 1 second. If voltage is not as specified, check inertia switch and electrical system.
3. Using ohmmeter, check continuity directly at high pressure fuel pump terminals. If no continuity, replace high pressure fuel pump.
4. Connect the ohmmeter across body wiring harness connector. If continuity is present (about 5 ohms), low pressure pump circuit is OK.
5. If no continuity is present in previous step, remove fuel tank and check continuity at fuel pump/pump sender flange terminals. If no continuity is present at pump flange terminals, replace the assembly. (Scheme 6)

Fuel Pump Wiring Diagram All except Crown Victoria, Grand Marquis, and Town Car. Scheme 6

Fuel Pump Operation (All Models)

1. Disconnect fuel return line at fuel charging main body and connect hose to a calibrated container (at least 1 quart capacity). Connect pressure gauge to fuel pressure test fitting.
2. Unplug electrical connector to fuel pump located ahead of fuel tank. Connect jumper wire to connector of fuel pump. Energize pump for 10 seconds by connecting wire to fully charged 12 volt battery.
3. Observe fuel pressure while pump is energized. Allow fuel to drain into container and observe volume of fuel discharged. De-energize pump and note pressure.
4. Fuel pump is operating properly if fuel pressure reaches 35-45 psi (2.46-3.16 kg/cm 2 ), fuel flow is 9.5 oz. (280 ml) in 10 seconds (minimum), and fuel pressure maintains minimum 30 psi (.2 kg/cm 2 ) immediately after de-energization.
5. If pressure condition is met, but fuel flow is not met, check for blocked filter(s) and fuel supply lines. After correcting problem, repeat test procedure. If fuel flow still does not meet specifications, replace fuel pump.
6. If flow specification is met, but pressure is not met, check for worn or damaged pressure regulator valve on throttle body.
7. If both pressure and fuel flow specifications are met, but pressure will not maintain after de-energization, check for leaking injector valve(s) and/or pressure regulator valve. If injector valve(s) and pressure regulator valve are okay, replace fuel pump.

Fuel Pump Operation (All Models Except Crown Victoria, Grand Marquis, & Town Car)

If hot fuel problems exist or system is noisy, check the low pressure in-tank fuel pump as follows

1. Remove inlet fuel line from high pressure fuel pump. Raise end of fuel line above level of fuel tank to prevent siphon action.
2. Place hose from fuel tank to a calibrated container of at least 1 quart capacity. Turn ignition switch to "ON" position until fuel runs out (about 1 second).
3. There should be a minimum of 1.5 oz. (45 ml) for 1 second of operation. If no fuel is present, turn ignition on and off 2 or 3 times.
4. If there is still no fuel is present, check for pinched line between fuel tank and fitting. To check electrical circuit, drop fuel tank.
5. Attach a voltmeter to chassis electrical connector from low pressure fuel pump and turn ignition on. Voltage should rise above battery voltage for 1 second and then return to 0 volts.
6. If voltage is as specified, replace fuel pump assembly and repeat test of low pressure pump. If no voltage is present, repair electrical circuit.

Exploded View of Throttle Body & Fuel Charging Assembly Illustration applies to 5.0L engine only; 3.8L is similar. Scheme 7

FUEL PRESSURE REGULATOR TEST

Connect fuel pressure gauge to pressure test fitting on fuel charging main body. Start engine and run at idle. Pressure reading should be 35-45 psi (2.46-3.16 kg/cm 2 ). If not to specification, check fuel lines for kinks and perform fuel pump tests.

Visual Leak Test

1. Remove air cleaner. Pressurize fuel system by turning key on and off 5 times with 1 second periods on before switching off. Visually observe injectors for any sign of leakage.
2. If no leakage is observed or leakage is less than 1 drop of fuel per minute, injectors are OK. If injectors discharge or leak more than 1 drop of fuel per minute, turn key off.
3. Unplug electrical connectors from both injectors. Pressure fuel system as in step 1). Observe injector for leaks again.
4. If no leaks are observed, or leakage is less than 1 drop of fuel in 1 minute, then injectors are OK. Check for improper electrical signal to injector. CAUTION: DO NOT apply voltage directly to injectors.
5. If leakage is still greater than 1 drop per minute, replace leaking injectors.

Leak Down Test

1. Connect fuel pressure gauge to pressure test fitting on fuel charging main body. Engine must be at normal operating temperature. Fuel pressure must be 35-45 psi (2.46-3.16 kg/cm 2 ) with engine running.
2. Observe pressure after 2 minutes. If pressure drops more than 4 psi (.28 kg/cm 2 ), replace injector. If pressure is within specification, go to step 3).
3. Turn ignition off. Unplug left injector. Ensure fuel system is pressurized. Disable fuel pump by disconnecting inertia switch or fuel pump relay. Crank engine for 2 seconds. Turn ignition off.
4. Wait 5 seconds, observe pressure drop. Pressure drop must be between 2 to 14 psi (.14-.98 kg/cm 2 ). Replace injector if pressure drop is greater than specified.
5. Connect left injector. Repeat steps 3) and 4) for right injector.

Injector Balance Test

1. Disconnect and plug vacuum hose to EGR valve. Start and run engine at 2000 RPM. Unplug left injector electrical connector. Note RPM drop after engine stabilizes. Reconnect left injector and stabilize RPM at 2000 RPM.
2. Perform same procedure for right injector. On 3.8L engine, RPM drop must be at least 150 RPM for each injector. On 5.0L engine, there must at least a 100 RPM drop. Replace any defective injectors.

Note. Refer to FORD MOTOR CO. EEC-IV ENGINE CONTROL SYSTEM in the COMPUTERIZED ENGINE CONTROLS section for test of oxygen sensor and ISC motor.

SENSOR/SOLENOID TESTS

If system difficulties imply sensor or solenoid problems, suspected components should be checked for resistance value. Component must be disconnected from the circuit before testing. Replace component if resistance is incorrect.

EFI SYSTEM COMPONENT RESISTANCE VALUES

REMOVAL & INSTALLATION

Removal

Remove air cleaner assembly. Relieve fuel pressure at Schrader valve on fuel charging main body. Remove all throttle control linkage, vacuum lines, fuel lines, and electrical connections. Remove throttle body retaining nuts and throttle body.

Installation

Install throttle body assembly in reverse order of removal, using new gasket between throttle body and intake manifold. Adjust idle speed if necessary. Check T.V. cable adjustment after replacement of throttle body assembly.

FUEL INJECTORS & FUEL PRESSURE REGULATOR

Note. Metric fasteners are painted Blue.

1. Remove throttle body assembly. Place on stand in inverted position. Remove 4 screws from base of throttle body and air cleaner stud. Remove throttle body from upper fuel charging main body.
2. Remove 3 fuel pressure regulator retaining screws and remove regulator. Remove nut holding injector retaining bracket to upper body and remove retaining bracket. Disconnect wiring harness from injectors and remove injectors from upper body, noting location of each.

1. Lubricate injector "O" rings with light oil and install on injectors. Push injectors into their original location. Install retainer bracket and nut.
2. Replace pressure regulator "O" ring and gasket. Lubricate "O" ring with light oil. Install pressure regulator and 3 screws. Install connectors on injectors.
3. Assemble throttle body to upper fuel charging main body using new gasket. Install throttle body on manifold.

1. Note position of index mark on choke cap housing. Drill rivet heads from bimetal cover retaining ring with a .128" (No. 30) drill. Drive remaining portion of rivet body from housing. Remove bimetal cover retaining ring and cover.
2. Remove thermostat lever screw and lever. Remove fast idle cam assembly. Remove fast idle control rod positioner. Hold pulldown diaphragm cover tightly in position. Remove 2 screws and fast idle pulldown cover. Remove spring, spring retainer and pulldown diaphragm.

1. Install pulldown diaphragm with vacuum passage in diaphragm toward top of housing. Holding spring and spring retainer on diaphragm, carefully install pulldown cover and screws.
2. Install fast idle control bimetal to original position. Position cap retainer on cap, making sure all holes line up. Install new retaining rivets (1/8" diameter by 1/2" long by 1/4" head).

Removal (In-Tank Pump)

Relieve fuel system pressure. Remove fuel tank. Disconnect supply and return lines and electrical connector. Turn fuel pump lock ring counterclockwise and remove. Remove fuel pump assembly and seal. Discard seal.

Note. Whenever the fuel pump is removed from the tank, the rubber hoses, clamps and mounting gasket must be replaced. If not replaced, hoses could become brittle and deteriorate.

Install new seal and hold in place with heavy grease. Install gasket, pump unit and locking ring. Ensure seal does not move and locating keys are in keyways. Connect fuel lines and electrical connector. Install fuel tank.

Removal (High Pressure In-Line Pump)

Relieve fuel system pressure. Unplug electrical connector from body harness. Remove inlet and outlet lines from fuel pump. Remove fuel pump from assembly by bending tab out and sliding pump out of the ring.

1. Ensure fittings on pump have new gaskets in place and are tightened properly. Wiring harness terminals must be pushed onto pump terminals far enough to seal.
2. Wrap isolator around pump, locating slot in isolator so it faces bracket base. Push pump and isolator into bracket.
3. Tab of isolator must contact tab of bracket, and bracket tabs must not contact pump case. Bend rear tab to secure pump. Connect fuel lines and electrical harness.

1. On 5.0L engines, remove retaining nut from fast idle side of throttle shaft. Remove fast idle cam adjuster lever, fast idle actuating lever and "E" clip from throttle shaft.
2. On 5.0L and 3.8L engines, scribe a locating mark on TPS and throttle body, remove TPS retaining screws and TPS.

Align TPS and throttle body scribe marks. Hold firmly against throttle body and install screws. Install "E" clip, fast idle levers (if equipped) and retaining nut.

ELECTRONIC CONTROL ASSEMBLY (ECA) & SENSORS

Note. No removal and installation procedures available from manufacturer. If engine sensors are removed, install using sealing compound on threads.

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

Ford 3.8L V6 EFI (EEC IV) System Wiring Diagram. Scheme 8

Ford 5.0L V8 EFI (EEC IV) System Wiring Diagram. Scheme 9