Fuel Injection System - High Pressure Cfi Ford Thunderbird IX

COMPONENT TESTING

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

DESCRIPTION

The High Pressure Central Fuel Injection System is a single point system that is pulse time modulated. 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 DELIVERY

Fuel is supplied from the fuel tank by a high pressure electric fuel pump. Pump is mounted in the fuel tank. The fuel is filtered and sent to the throttle body, where a regulator keeps the fuel delivery pressure at a constant 39 psi (2.7 kg/cm 2 ).

Fuel Charging System. Scheme 2

Two injector nozzles are mounted vertically above the throttle plates and connected in parallel with the fuel pressure regulator. Excess fuel supplied by the pump, but not needed by the engine, is returned to the fuel tank by a steel fuel return line.

The fuel charging assembly consists of 6 individual components which perform the fuel and air metering function to the engine. The throttle body assembly mounts to the conventional carburetor pad of the intake manifold. Throttle body provides for packaging of air control, fuel injector nozzles, fuel pressure regulator, fuel pressure diagnostic valve, cold engine speed control, and throttle position sensor.

Cutaway View of Injector Valve. Scheme 3

AIR CONTROL

Air flow to the engine is controlled by 2 butterfly valves mounted in a 2-piece aluminum throttle body. The butterfly valves are identical in configuration to the throttle plates of a conventional carburetor and are actuated by a similar linkage and pedal cable arrangement.

FUEL INJECTOR NOZZLES

The fuel injector nozzles are mounted vertically above the throttle plates. They are electro-mechanical devices which meter and atomize the fuel delivered to the engine. The injector valve bodies consist of a solenoid actuated pintle and needle valve assembly.

An electrical control signal "pulse width" from the ECA activates the solenoid, causing the pintle to move inward off its seat, thus allowing fuel to flow. The injector flow orifice is fixed and the fuel supply pressure is constant, therefore, fuel flow to the engine is controlled by how long the solenoid is energized.

FUEL PRESSURE REGULATOR

The pressure regulator mounts to the fuel charging main body near the rear of the air horn surface. The regulator is located strategically to avoid the effects of the supply line pressure drops. Its design is such that it is not sensitive to BACK PRESSURE in the return line to the tank.

A second function of the pressure regulator is to maintain fuel supply pressure upon engine and fuel pump shutdown. The regulator functions as a downstream check valve and traps the fuel between itself and the fuel pump.

The maintenance of fuel pressure upon engine shutdown precludes fuel line vapor formation. It also allows for rapid restarts and stable idle operation immediately after restart. It regulates the fuel pressure to the injector nozzles at a constant nominal value of 39 psi (2.7 kg/cm 2 ).

FUEL PRESSURE DIAGNOSTIC VALVE

The diagnostic pressure valve (Schrader type) is located at the top of the fuel charging main body. This valve provides a convenient point for service personnel to monitor fuel pressure, bleed down the system pressure prior to maintenance, and to bleed out air which may have been introduced at assembly plant start up or filter servicing.

5.0L Engine Only

The additional engine speed required during cold idle is accomplished by a throttle stop cam positioner similar to that used on conventional carburetors. The cam is positioned by a bimetal spring and an electric positive temperature heating element.

The electrical source for the heating element is 7.3 volts from the alternator stator which provides voltage only when the engine is running. The heating element is designed to provide the necessary warm-up profile in accordance to the starting temperature (cold engine prior to crank) and the length of time after starting. Multiple positions on the cam profile allow for a decreasing cold engine speed to curb idle speed during warm-up.

A second feature of the cold engine speed control is automatic kickdown from high speed. This is accomplished by the ECA vacuum to the automatic kickdown motor which physically moves the high speed cam a predetermined time after the engine starts.

3.8L Engine Only

The Idle Speed Control Motor (ISC) controls idle speed by modulating the throttle lever. This regulates airflow to maintain the desired engine RPM for both "Warm" engine and the additional engine speed required during "Cold" engine idle.

An Idle Tracking System (ITS), integral to the ISC motor, is utilized to determine when the throttle lever has contacted the actuator. This signals the need to control engine RPM. The ISC motor extends or retracts a linear shaft through a gear reduction system. The motor direction is determined by the polarity of the applied voltage.

THROTTLE POSITION SENSOR

This non-adjustable sensor is mounted to the throttle shaft on the choke side of the fuel charging assembly. It is used to supply a voltage output proportional to the change in the throttle plate position. The sensor is used by the ECA to determine the operational mode (closed throttle, part throttle, and wide open throttle) for selection of the proper fuel mixture, spark and EGR at selected driving ranges.

INERTIA SWITCH

In the event of a collision, the electrical contacts in the inertia switch open and the fuel pump automatically shuts off. The fuel pump will shut off even if the engine does not stop running. The engine, however, will stop a few seconds after the fuel pump stops. It is not possible to restart the engine until the inertia switch is manually reset.

PRELIMINARY CHECKS

Following systems and components must be in good condition and operating properly before beginning diagnosis of fuel injection system

1. All support systems and wiring.
2. Battery connections and specific gravity.
3. Ignition system.
4. Compression pressure.
5. Fuel supply system pressure and flow.
6. All electrical connections and terminals.
7. Vacuum line, fuel hose and pipe connections.
8. Air cleaner and air ducts.
9. Engine coolant level.

TROUBLE SHOOTING

Note. Some vehicles may not include all components listed in this section.

Engine Does Not Crank

Check for hydrostatic lock (liquid in cylinder) and repair as needed. Check for starting and charging system problems.

Engine Cranks But Does Not Start

1. See that fuel tank contains an adequate amount of fuel. DO NOT assume that fuel gauge is correct.
2. Check ignition system for strong secondary current at spark plugs. If none exists or current is weak, repair ignition system problem before continuing with fuel injection diagnosis.
3. Check fuel lines and fittings for leaks. If no leaks are found, check fuel delivery system for proper operation, pressure and volume.
4. Reset inertia switch if necessary.

Hard to Start - Cold

1. Cold enrichment system may not be functioning correctly. Check TPS and ISC motor for proper operation and adjustment. Adjust or replace as required.
2. Choke thermostat housing may be incorrectly adjusted. Adjust choke thermostat setting if needed. If it is a tamper-proof type, check for incorrect assembly.
3. Intake manifold or fuel charging assembly gaskets may be leaking. Replace leaking gaskets as needed.

Rough Idle - Cold

1. Cold enrichment system may not be functioning correctly. Check fast idle system for proper operation and adjustment. Adjust or replace as required.
2. Fast idle adjustments may be improper. Perform fast idle adjustments.
3. Air cleaner duct vacuum motor may be damaged or stuck open. Replace or service as required.
4. Check for possible vacuum leak.

Stall, Stumble, Hesitation - Hot or Cold

1. Cold enrichment system may not be functioning correctly. Check for proper operation and adjustment. Adjust or replace as required.
2. Fuel pump output may be low. Service or replace as required.
3. Fuel filter may be clogged. Clean or replace as required. Determine cause.
4. Air cleaner vacuum motor may be damaged. Service or replace as required.

Hard Start - Hot

1. Cold enrichment system may not be functioning correctly. Check for proper operation and adjustment. Adjust or replace as required. Fuel pressure may be incorrect. Check fuel pressure regulator.
2. Choke thermostat housing may be incorrectly adjusted. Adjust choke thermostat setting if needed. If it is a tamper-proof type, check for incorrect assembly.
3. Intake manifold or fuel charging assembly gaskets may be leaking. Replace leaking gaskets as needed.

Rough Idle - Hot

Ignition system could be malfunctioning. Check for possible intake vacuum leaks.

Stalls on Deceleration or Quick Stop

Throttle positioner may be functioning improperly. Service as required. Intake manifold or fuel charging assembly gaskets may be leaking. Replace leaking gaskets as needed.

Lack of Power

Fuel filter may be clogged. Check fuel delivery and repair as needed.

Reduced Top Speed/Power

1. Throttle linkage may be binding. Clean and service as required.
2. Fuel pump volume may be low. Test fuel delivery system.
3. Fuel filter may be clogged. Replace as required. Determine cause.
4. Injectors may be plugged. Repair or replace as needed.
5. Pressure regulator may be damaged. Repair or replace as needed.

Surge at Cruise

1. Fuel filter may be clogged. Replace filter. Determine cause.
2. Fuel pump pressure or volume may be low. Test fuel delivery system.
3. Fuel may be contaminated. Drain fuel and clean system as needed.

1. The inertia switch is located in the luggage compartment on the left hinge support on Cougar, Crown Victoria, Grand Marquis (sedan only), Town Car, Thunderbird and Mustang and Capri 2-door models.
2. The Mustang/Capri switch is located near the left hand tail lamp area on 3-door models. The inertia switch is located in the left side storage compartment on Crown Victoria and Grand Marquis station wagons. To reset the inertia switch, depress button on the switch.

Fuel Pump Wiring Diagrams (Lincoln Mark VII & Continental). Scheme 4

Fuel Pump Wiring Diagrams (Crown Victoria, Grand Marquis & Lincoln Town Car). Scheme 5

Fuel Pump Wiring Diagram (All Except Crown Victoria, Grand Marquis & Lincoln Models). Scheme 6

FUEL DELIVERY SYSTEM

1. Check fuel tank for adequate fuel supply. Check for fuel leakage at all fittings and lines.
2. Check for electrical continuity to the fuel pump(s). On a single pump system, disconnect electrical connector just forward of the fuel pump inlet. On dual pumps, disconnect electrical connector to fuel pumps at high pressure pump module. Connect voltmeter to body wiring harness connector. Turn ignition key to "ON" position while watching the voltmeter.
3. Voltage should rise to battery voltage and then return to zero voltage after approximately one second. If voltage is not as specified, check inertia switch and electrical system. Connect ohmmeter to pump wiring harness connector. If no continuity is present, check continuity directly at pump terminals. If no continuity is at pump terminals, replace pump(s). If continuity is present at pump terminals, service and replace wiring harness.
4. For dual pump systems only, connect the ohmmeter across the body wiring harness connector. If continuity is present (about 5 ohms), low pressure pump circuit is electrically okay.
5. For dual pump systems only, if no continuity is present in step 4), it is necessary to remove fuel tank and check for continuity at fuel pump/pump sender flange terminals. If no continuity at pump flange terminals is present, replace the assembly. If continuity is present at pump but not in step 4), service or replace the wiring harness in the low pressure pump.
6. Check operation of fuel pump(s). Disconnect return line at fuel rail. Use care to avoid spillage. Connect hose from fuel rail fitting to a calibrated container of at least one quart. Connect pressure gauge to fuel diagnostic valve on fuel rail. Disconnect the electrical connector to the electric fuel pump(s) located just forward of the pump outlet.
7. Connect auxiliary wiring harness to the electrical connector to the fuel pump. Energize the fuel pump(s) for 10 seconds by connecting the auxiliary wiring harness to a fully charged 12-volt battery. Observe pressure while energized. If no pressure, check polarity of wiring harness and also check terminal connections at fuel pump(s).
8. Allow fuel to drain from hose into container and observe the volume. The fuel pump(s) are operating properly if: fuel pressure reaches 35-45 psi (2.5-3.2 kg/cm 2 ), fuel flow is a minimum of 7.5 oz. (220 cc) for a single pump system; 9.5 oz. (280 cc) for a dual pump system, in 10 seconds, and fuel pressure remains at a minimum of 30 psi (2.1 kg/cm 2 ) immediately after de-energizing.
9. If all 3 conditions are met, the fuel pump is operating normally. If pressure condition is met but flow is not, check for blocked filter(s) and fuel supply lines. After correcting any blockage, recheck using step 8). If flow conditions are still not met, replace fuel pump.
10. If both pressure and flow conditions are met but pressure will not maintain after de-energizing, check for leakage at the regulator or injectors. If both check okay, then replace fuel pump.
11. If no flow or pressure is seen, the fuel system should be checked as in step 9). If no trouble is found, replace the fuel pump. Drop the fuel tank and replace the fuel filter on the filler neck tube or on the low pressure pump, depending on application.
12. On a system with 2 fuel pumps, if hot fuel problems exist or system is noisy, check the low pressure in-tank pump as follows. Remove inlet push connect fitting and line from high pressure pump assembly. CAUTION: Raise end of fitting above level of fluid in tank to prevent a siphon action.
13. Connect hose from fuel tank to a calibrated container of at least one quart. Place ignition key in the "RUN" position until fuel pump times out (approximately one second). Check container for presence of fuel (if necessary, lift container to prevent siphon action). The amount of fuel should be a minimum of 1.5 oz. (50 cc) for one second of operation.
14. If no fuel is present, recycle ignition key. If no fuel is present, check for a pinched line between the fuel tank and fitting, and then proceed to drop the fuel tank.
15. Connect a voltmeter to the chassis electrical connector from the fuel pump and turn ignition key to "ON" position. Voltage should rise to battery voltage for one second and then return to zero volts. If voltage is as specified and electrical connector was okay at pump, replace fuel pump assembly and repeat low pressure fuel pump test. If no voltage is present, service electrical circuit in vehicle.

Removal

1. Remove air cleaner. Release pressure from the fuel system at the diagnostic valve on the fuel charging assembly using diagnostic tool (T80L-9974-A). Disconnect the throttle cable and transmission throttle valve lever.
2. Disconnect fuel, vacuum and electrical connections. Remove fuel charging assembly retaining nuts. Remove fuel charging assembly. Remove mounting gasket from intake manifold.

Installation

1. Clean gasket mounting surface. Place spacer between 2 new gaskets and place spacer and gaskets on the intake manifold. Position the charging assembly on the spacer and gasket. Secure the fuel charging assembly with attaching nuts.
2. Snug the nuts, and then tighten alternately and evenly to prevent leakage or distortion. Connect the fuel line, electrical connectors, throttle cable and all emission lines. Start the engine and check for leaks.

Fuel Charging Assembly

1. Place the fuel charging assembly on a work stand or use bolts as legs. Four 5/16 x 2-1/2" bolts can be used as legs with nuts installed above and below throttle body.
2. Remove the air cleaner stud. Turn the fuel charging assembly over and remove the 4 retaining screws attaching the throttle body to the main body. Separate the throttle body from main body and set aside.
3. Remove and discard the gasket. Remove the 3 fuel pressure regulator retaining screws. Remove pressure regulator. Inspect the condition of gasket and "O" ring. Disconnect the electrical connectors at each injector.
4. Pull the connectors outward, being careful to pull on connector, not wire. Make sure to index mark the connectors for reassembly reference. Loosen but do not remove the wiring harness retaining screw with multi-connector.
5. Loosen 2 retaining screws to the 10-pin connector. Push in on tabs on harness to remove upper body. Remove the fuel injector retainer screw and injector retainer. Pull out injectors from upper body, one at a time.
6. Identify each injector as choke or throttle side. If "O" ring does not come out with injector, carefully pick it out of cavity in throttle body. Remove fuel diagnostic valve assembly.

Exploded View of Throttle Body and Fuel Charging Assembly. Scheme 7

Throttle Body Assembly

1. Note the position of index mark on choke cap housing. Remove 3 retaining ring screws. Remove choke cap retaining ring, choke cap and gasket. Remove thermostat lever screw and lever (if equipped). Carefully remove cover, spring and pull-down control diaphragm (if equipped).
2. Remove fast idle retaining nut (if equipped). Remove fast idle cam adjuster lever, fast idle lever, spring and "E" clip (if equipped). Remove the throttle position sensor connector bracket retaining screw.
3. Remove throttle position sensor retaining screws. Slide throttle position sensor off the throttle shaft. If CFI assembly is equipped with a throttle positioner, remove throttle positioner retaining screw, and remove positioner. If the CFI assembly is equipped with an ISC DC motor, remove the motor.

Upper Body

1. Install fuel pressure diagnostic valve and cap and tighten. Lubricate new "O" rings with a light grade oil and install on each injector. Identify injectors and install them in their appropriate locations (choke or throttle side). Use a light twisting motion to install injectors.
2. With injectors installed, install injector retainer into position and tighten screws. Install injector wiring harness in upper body. Snap harness into position. Tighten harness retaining screw (2 screws if equipped with a 10-pin connector).
3. Snap electrical connector into position on injectors. Lubricate new fuel pressure regulator "O" ring with light oil. Install "O" ring and new gasket on regulator. Install pressure regulator in upper body.

Throttle Body

1. Install either throttle positioner or the ISC DC motor. Hold throttle position sensor wire face up. Slide throttle position sensor on throttle shaft. Rotate throttle position sensor clockwise until aligned with screw holes on throttle body.
2. Install retaining screws and tighten. Install "E" clip, fast idle lever and spring. Install fast idle adjustment lever and fast idle retaining nut (if equipped). Tighten fast idle retaining nut.
3. Install pull-down control diaphragm, control modulator spring and cover (if equipped). Hold cover in place and install 2 retaining screws. Install fast idle control rod positions (if equipped). Install fast idle cam (if equipped).
4. Install thermostat lever and retaining screws (if equipped). Install choke cap gasket, choke cap and retaining ring (if equipped). Be sure that the choke cap bimetal spring is properly inserted between fingers of thermostat lever and that choke cap index mark is properly aligned.
5. Install choke cap retaining screws. Install fuel charging gasket on upper body. Be sure gasket is positioned over bosses. Place throttle body in position on upper body. Install 4 screws retaining upper throttle body to upper body. Install air cleaner stud.

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

3.8L and 5.0L High Pressure CFI System Wiring Diagram. Scheme 8