Fuel Injection System - Multi-Point Ford Bronco II I

COMPONENT TESTING

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

DESCRIPTION

The Electronic Fuel injection (EFI) system is a pulsed time, speed density, fuel injection system. Fuel is metered into intake air stream, according to engine demand, through injectors mounted on a tuned intake manifold.

An on-board Electronic Engine Control (EEC-IV) module accepts inputs from various engine sensors to compute required fuel flow necessary to maintain correct air/fuel ratio throughout engine RPM range.

The EEC-IV module sends a command to injectors to meter approximate quantity of fuel. System will automatically sense and compensate for changes in altitude and will permit push-starting vehicle (manual transmissions only).

FUEL DELIVERY

The fuel delivery sub-system consists of a low pressure, in-tank fuel pump, a fuel filter/reservoir, and a high pressure electric fuel pump. Pump delivers fuel from fuel tank through a 20-micron fuel filter to a fuel charging manifold assembly. The fuel charging manifold assembly incorporates electrically actuated injectors directly above each engine intake port.

When energized, injectors spray a metered quantity of fuel into intake air stream. The length of time that injectors are energized (injector "on time" or "pulse width") is controlled by EEC-IV module. A constant fuel pressure is maintained across injector nozzles by a fuel pressure regulator.

FUEL PRESSURE REGULATOR

The fuel pressure regulator is positioned downstream from injectors. Excess fuel not required by engine passes through regulator and returns to fuel tank through a fuel return line.

The regulator is a diaphragm operated relief valve. One side of diaphragm senses fuel pressure and other side senses intake manifold vacuum. Nominal fuel pressure is established by an applied spring preload on diaphragm. Balancing one side of diaphragm with manifold pressure maintains a constant fuel pressure across injectors.

AIR THROTTLE BODY ASSEMBLY

The air throttle body assembly controls air flow to engine through a single or a double butterfly valve. Throttle position is controlled by multiple-link, progressive opening throttle linkage, or a conventional cable/cam throttle linkage.

A by-pass channel on air throttle body assembly controls both cold and warm engine idle as regulated by an air by-pass valve assembly mounted to air cleaner (2.3L engine), upper intake manifold (2.9L engine), or throttle body (3.0L, 4.9L and 5.0L engines). The by-pass valve assembly is an electro-mechanical device controlled by EEC-IV module.

The air throttle body assembly incorporates a linear actuator which positions a variable area metering valve. It also features a preset stop to locate W.O.T. position, a throttle position sensor, canister purge ports for evaporative emission control (2.9L and 5.0L engines).

In addition, the air throttle valve assembly incorporates an adjustment screw to set throttle plate at minimum idle (2.3L and 3.0L engines), crankcase ventilation pressure tube (2.9L engine), closed throttle stop-set screw (2.9L engine), provision for EGR valve and sensor mounting (3.0L engine), a built in torsional return spring (3.0L engine), and individual ported vacuum taps for PCV and EVAP control signals (3.0L engine).

On the 4.9L engine, the air throttle valve assembly idle speed screw engages the secondary throttle lever (AOD transmission) and it engages the primary throttle lever for the C6 automatic transmission and all manual transmissions.

FUEL SUPPLY MANIFOLD ASSEMBLY

The fuel supply manifold assembly delivers fuel at high pressure from vehicle fuel supply line to injectors. Assembly consists of 2 banks of stamped fuel rails connected by a crossover connection (5.0L engine), or 2 preformed tubes or stampings, one for fuel supply and one for fuel return (2.3L and 2.9L engines). On 3.0L and 4.9L engines, the assembly consists of a single preformed tube with one connector for each injector.

Fuel pressure manifold assembly has injector connectors and a mounting flange to fuel pressure regulator. It also has mounting attachments which locate fuel manifold assembly and provide injector retention. On 2.3L, 2.9L and 3.0L engines, a fuel pressure relief valve is installed on fuel supply manifold assembly to release fuel system pressure.

FUEL INJECTORS

The injector nozzles meter and atomize fuel delivered to engine. Injectors are mounted in lower intake manifold and direct fuel just ahead of engine intake valves.

Injector body consists of a solenoid actuated pintle and needle valve assembly. An electrical control signal from EEC-IV module activates injector solenoid, causing pintle to move upward off seat, allowing fuel to flow.

Since injector flow orifice diameter is fixed and fuel pressure drop across injector tip is constant, fuel flow to engine is regulated by length of time solenoid remains energized. Atomization is obtained by contouring pintle at point where fuel separates.

INTAKE MANIFOLD

The intake manifold is a 2-piece (upper and lower) aluminum casting. Runner lengths are tuned to optimize engine torque and power output. Manifold provides mounting flanges for throttle body assembly, fuel supply manifold, accelerator control brackets, EGR valve and supply tube.

Vacuum taps are provided to support various engine accessories. Pockets for injectors are machined to prevent air and fuel leakage. Pockets in which injectors are mounted are placed to direct injector fuel spray immediately in front of each intake valve.

TROUBLE SHOOTING

Refer to appropriate article in COMPUTERIZED ENGINE CONTROLS section for specific testing procedures.

Verify all basic systems are operating properly before testing computerized components. Check cooling system, charging system, battery, all vacuum hoses and electrical connections, spark plugs and spark plug wires, etc.

Check fuel pump for pressure and volume. See ELECTRIC FUEL PUMPS article in this section.

Removal & Installation (2.3L Engine)

1. Remove fuel tank and pressure relief valve caps. Install EFI Pressure Gauge (T80L-9974-A) at pressure relief valve to depressurize fuel system. Relief valve is located in upper right hand corner of engine compartment.
2. Disconnect wiring harness from injectors. Remove fuel supply manifold retaining bolts. Carefully disengage manifold and fuel injectors from engine. Remove manifold and injectors.
3. To install, lubricate new "O" rings with a light oil and install 2 on each injector (one per injector if injectors were not removed from fuel supply manifold). DO NOT use silicone grease.
4. Install fuel injector supply manifold and injectors in intake manifold, ensuring injectors are seated. Secure fuel manifold assembly with retaining bolts. Connect injector wiring harness. (Scheme 1)

2.3L Engine Multi-Point Fuel Injection System. Scheme 1

Removal & Installation (2.9L Engine)

1. Open hood and install protective covers. Disconnect negative battery cable. Remove air inlet tube from air cleaner to throttle body. Remove fuel cap to relieve tank pressure.
2. Disconnect vacuum hose from fuel pressure regulator. Using a hand vacuum pump, apply about 25 in. Hg pressure to pressure regulator. Fuel system pressure will be released through fuel return hose.
3. Remove upper intake manifold and throttle body assembly. See «UPPER INTAKE MANIFOLD & THROTTLE BODY ASSEMBLY R & I»(/ford/bronco-ii/i-1984-1990/remont/testing-diagnostics/#fuel-injection-system-multi-point) in this article. Disconnect crossover fuel hose, fuel supply, and fuel return line from fuel supply manifold. See «PUSH-CONNECT FITTINGS R & I»(/ford/bronco-ii/i-1984-1990/remont/testing-diagnostics/#fuel-injection-system-multi-point) in this article.
4. Remove fuel supply manifold retaining bolts. Carefully remove fuel supply manifold from lower intake manifold. The fuel injectors are retained in fuel supply manifold with clips.
5. Remove retainer clips and inspect for corrosion and damage. Remove injector(s) from fuel supply manifold and wipe cup with clean dry cloth.
6. To install, ensure injector caps and injector recesses are clean and free of contamination. Lightly grease recesses. Install 3 injectors on right side recess of intake manifold, and then 3 on left.
7. Position and press down firmly until attachment holes line up and install fasteners. To complete installation, reverse removal procedure. (Scheme 2)

2.9L Engine Multi-Point Fuel Injection System. Scheme 2

Removal & Installation (3.0L Engine)

1. Remove air intake throttle body. See «AIR INTAKE THROTTLE BODY R & I»(/ford/bronco-ii/i-1984-1990/remont/testing-diagnostics/#fuel-injection-system-multi-point) in this article. Disconnect fuel supply and return lines. See «PUSH-CONNECT FITTINGS R & I»(/ford/bronco-ii/i-1984-1990/remont/testing-diagnostics/#fuel-injection-system-multi-point) in this article. Disconnect wiring harness at fuel injectors.
2. Disconnect vacuum hose from fuel pressure regulator. Remove fuel assembly manifold bolts (2 on each side). Carefully disengage fuel supply manifold from fuel injectors by lifting and gently rocking rail.
3. Remove injectors from fuel supply manifold by using a slight twisting/pulling motion. (Scheme 3) Place removed components in a clean container to avoid dirt or other contamination.
4. Lubricate new injector "O" rings with a light oil. DO NOT use silicone grease. Carefully install fuel supply manifold and injectors into lower manifold, one side at a time. To complete installation, reverse removal procedure.

3.0L Engine Multi-Point Fuel Injection System. Scheme 3

Removal & Installation (4.9L Engine)

1. Remove upper intake manifold assembly. See «UPPER INTAKE MANIFOLD & THROTTLE BODY ASSEMBLY R & I»(/ford/bronco-ii/i-1984-1990/remont/testing-diagnostics/#fuel-injection-system-multi-point) in this article. Disconnect fuel supply and fuel return lines. See «PUSH-CONNECT FITTINGS R & I»(/ford/bronco-ii/i-1984-1990/remont/testing-diagnostics/#fuel-injection-system-multi-point) in this article.
2. Remove injector cooling manifold from engine lifting eye attachment. Remove injector cooling manifold attaching nut from fuel rail stud. Remove injector cooling manifold.
3. Disconnect electrical lead from fuel manifold temperature switch. Disconnect vacuum hose from fuel pressure regulator. Remove strap surrounding fuel supply manifold, injector electrical harness, and main vacuum harness.
4. Remove 3 fuel supply manifold retaining studs. Carefully disengage fuel supply manifold from fuel injectors and remove manifold. To install, reverse removal procedure.

Removal & Installation (5.0L Engine)

1. Open hood and install protective covers. Remove fuel tank cap. Locate and disconnect electrical lead at fuel pump relay, inertia switch, or in-line high pressure fuel pump.
2. Crank engine for 10 seconds. If engine starts, crank engine an additional 5 seconds after engine stalls. Reconnect electrical lead that was disconnected in step 1). Disconnect negative battery cable.
3. Remove upper intake manifold and throttle body assembly. Disconnect fuel supply and return line connections at fuel supply manifold. See «PUSH-CONNECT FITTINGS R & I»(/ford/bronco-ii/i-1984-1990/remont/testing-diagnostics/#fuel-injection-system-multi-point) in this article.
4. Remove fuel supply manifold retaining bolts. Carefully disengage fuel supply manifold from lower intake manifold. To install, reverse removal procedure.

5.0L Engine Multi-Point Fuel Injection System. Scheme 4

Removal (2.3L Engine)

1. Disconnect electrical leads at throttle position sensor and knock sensor. Disconnect vacuum hoses at upper intake manifold vacuum tee, EGR valve, and fuel pressure regulator.
2. Remove throttle linkage shield. Disconnect throttle linkage and cruise control cables. Unbolt accelerator cable from bracket and move cable aside. Disconnect air intake, air by-pass, and crankcase vent hoses.
3. Disconnect PCV hose from fitting on underside of upper intake manifold. Disconnect EGR tube from EGR valve by turning flange nut. Remove 4 upper intake manifold retaining bolts. Remove upper intake manifold and throttle body assembly.

Installation (2.3L Engine)

Clean gasket surfaces, but do not allow gasket material to fall into intake manifold. To install, reverse removal procedure.

Removal (2.9L Engine)

1. Disconnect electrical connectors at air by-pass valve, throttle position sensor, EGR sensor and Air Charge Temperature (ACT) sensor. Remove air inlet tube from air cleaner to throttle body.
2. Remove snow/ice shield to expose throttle linkage. Disconnect throttle cable from ball stud. Disconnect upper intake manifold vacuum connectors, both front and rear fittings including EGR valve, and vacuum line to fuel pressure regulator.
3. Disconnect PCV closure tube from under throttle body and disconnect PCV vacuum tube from under manifold. Remove canister purge line from fitting near power steering pump. Disconnect EGR tube from EGR valve by removing flange nut.
4. Loosen bolt retaining A/C line at upper rear of upper manifold and disengage retainer. Remove 6 upper intake manifold retaining bolts. Remove upper intake manifold and throttle body as an assembly.

Installation (2.9L Engine)

1. Clean and inspect mounting faces of lower and upper intake manifolds. Position new gasket on lower intake mounting face. Use of alignment studs may be helpful.
2. Install upper intake manifold and throttle body assembly to lower manifold making sure gasket remains in place. Align EGR tube in valve. Install 6 upper intake manifold retaining bolts and tighten.
3. Engage A/C line retainer cup and tighten bolt. Tighten EGR tube, flare fitting, and lower retainer nut at exhaust manifold. Install canister purge line to fitting.
4. Connect PCV vacuum hose to bottom of upper manifold and PCV closure hose to throttle body. Connect vacuum lines to vacuum tree, EGR valve, and fuel pressure regulator.
5. Connect throttle cable to throttle body and install snow/ice shield. Connect electrical connector at air by-pass valve, throttle position sensor, EGR sensor, and ACT sensor.

Note. If lower intake manifold was removed, fill and bleed cooling system.

Removal (3.0L Engine)

1. Open hood and install protective covers. Ensure ignition switch is in the "OFF" position. Disconnect negative battery cable and secure out of way. Remove fuel cap to relieve fuel tank pressure.
2. Remove pressure relief valve cap. Using EFI Pressure Gauge (T80L-9974-A), relieve fuel system pressure at fuel pressure relief valve (on fuel rail assembly).
3. Disconnect fuel supply and return lines. See «PUSH-CONNECT FITTINGS R & I»(/ford/bronco-ii/i-1984-1990/remont/testing-diagnostics/#fuel-injection-system-multi-point) in this article. Disconnect wiring harness at fuel injectors. Disconnect wiring harness at throttle position sensor, air by-pass valve, and Air Charge Temperature (ACT) sensor.
4. Loosen clamps and remove engine air outlet tube between air cleaner and air throttle body. If fuel supply manifold or if fuel injectors are being removed, remove snow shield by removing retaining nut on top of shield and 2 bolts on side.
5. Disconnect vacuum hoses at vacuum fittings on intake manifold. Disconnect and remove accelerator and cruise control cables from accelerator mounting bracket and throttle lever.
6. Remove 4 retaining bolts and 2 stud bolts. Lift air intake throttle body assembly from guide pins on lower intake assembly. Remove and discard gasket from lower intake manifold assembly.

Installation (3.0L Engine)

Clean and oil manifold bolt threads. Install new manifold gasket. If injectors were removed, lubricate new injector "O" rings with a light oil. DO NOT use silicone grease. To complete installation, reverse removal procedure. (Scheme 5)

3.0L Engine Upper Intake Manifold Tightening Sequence. Scheme 5

Removal (4.9L Engine)

1. Disconnect electrical leads at EGR valve position sensor, throttle position sensor, and air by-pass valve. Disconnect vacuum hoses at EGR valve, intake manifold vacuum tree, and fuel evaporative lines at throttle body.
2. Disconnect PCV hose from fitting located on side of intake manifold. (Scheme 6) Remove throttle linkage shield. Disconnect throttle linkage and cruise control cables. Disconnect accelerator cable from bracket and position cable away from engine.
3. Disconnect air inlet hoses from throttle body. Disconnect EGR tube from EGR valve and exhaust manifold. Remove EGR tube from engine. Remove thermactor (air injection) tube assembly from lower intake manifold.
4. Remove nut attaching thermactor by-pass valve bracket to lower intake manifold. On Vans, remove nut attaching transmission filler tube. Remove tube bracket from intake manifold stud.
5. On all models, remove 5 studs and 2 screws retaining upper intake manifold. Remove screw and washer attaching upper intake manifold support brakect to intake manifold. Remove upper intake manifold an throttle body as an assembly.

Installation (4.9L Engine)

To install, reverse removal procedure. Use new gasket between upper and lower intake manifolds.

4.9L Engine Upper Intake Manifold Assembly. Scheme 6

Removal (5.0L Engine)

1. Disconnect electrical leads at air by-pass valve, throttle position sensor, and EGR position sensor. Disconnect throttle linkage at pivot ball and AOD transmission linkage from throttle body.
2. Remove bolts securing bracket to intake manifold and position bracket with cables out of way. Remove vacuum hoses at upper intake manifold vacuum tee, EGR valve, and fuel pressure regulator.
3. Disconnect PCV system by removing hose from fitting on rear of upper intake manifold. Remove 2 canister purge lines from fitting on throttle body. Disconnect heater hoses from throttle body.
4. Disconnect EGR tube from EGR valve by turning flange nut. Remove upper intake manifold support bracket. Remove 6 manifold retaining bolts. Remove upper intake manifold and throttle body as an assembly.

Installation (5.0L Engine)

To install, reverse removal procedure. Use new gasket between upper and lower intake manifolds.

1. Open hood and install protective covers. Ensure ignition switch is in the "OFF" position. Drain engine coolant. Disconnect negative battery cable and position out of way. Remove fuel cap to relieve fuel tank pressure.
2. Remove pressure relief valve cap. Using EFI Pressure Gauge (T80L-9974-A), relieve fuel system pressure at fuel pressure relief valve (on fuel rail assembly).
3. Disconnect electrical leads at throttle position sensor, injector wiring harness, knock sensor, Air Charge Temperature (ACT) sensor, and engine coolant temperature sensor.
4. Disconnect upper intake manifold fitting connections by removing vacuum hoses from upper intake manifold vacuum tee, EGR valve, and fuel pressure regulator. Remove throttle linkage shield. Disconnect throttle linkage and cruise control cables.
5. Unbolt accelerator cable, and move cable aside. Disconnect air intake, air by-pass, and crankcase vent hoses. Disconnect PCV hose from fitting on underside of upper intake manifold.
6. Disconnect coolant by-pass hose at lower intake manifold. Disconnect EGR tube from EGR valve by removing flange nut. Remove 4 upper intake manifold retaining nuts. Remove upper intake manifold and air throttle body assembly.
7. Remove oil dipstick bracket retaining bolt. Disconnect fittings from fuel supply manifold and fuel return lines. Refer to «PUSH-CONNECT FITTINGS R & I»(/ford/bronco-ii/i-1984-1990/remont/testing-diagnostics/#fuel-injection-system-multi-point) in this article.
8. Disconnect electrical leads from all fuel injectors, and set wiring harness aside. Remove 2 fuel supply manifold retaining bolts. Carefully remove fuel supply manifold and injectors.
9. Remove injectors from fuel supply manifold by using a slight twisting/pulling motion. Remove 4 bottom retaining bolts from lower manifold. Remove 4 upper retaining bolts from lower manifold. Remove manifold.

Clean and oil manifold bolt threads. Install new lower manifold gasket and tighten manifold bolts in sequence. see scheme 7 Lubricate new injector "O" rings with a light oil. DO NOT use silicone grease. To complete installation, reverse removal procedure.

1. Disconnect negative battery cable. Remove air cleaner and intake duct from throttle body. Disconnect throttle cable and bracket. Disconnect EGR tube from EGR valve. Disconnect all vacuum hoses from upper intake manifold.
2. Disconnect electrical leads at throttle body, EGR pressure sensor, intake manifolds, and distributor. Disconnect fuel injector wiring harness. Remove upper intake manifold assembly.
3. Drain engine coolant. Disconnect and remove hose from outlet to radiator and heater supply. Remove distributor cap and spark plug wires as an assembly. Mark location of distributor rotor. Remove distributor hold-down clamp and remove distributor.
4. Remove rocker arm covers. Remove intake manifold attaching bolts and nuts and note their length during removal. Tap manifold lightly with a plastic mallet to break gasket seal. Lift off manifold and remove all old gasket material and sealing compound.

Scheme 7

1. Apply sealing compound to joining surfaces. Place intake manifold gasket into position. Ensure that tab on right bank cylinder head gasket fits into cut-out of manifold gasket. Apply sealing compound to attaching bolt bosses on intake manifold. Install intake manifold and tighten bolts in sequence. (Scheme 7)
2. Install distributor so rotor and housing are in same position as marked during removal. Install distributor hold-down clamp and attaching bolt. Install rocker arm covers.
3. Install distributor cap. Coat inside of each spark plug wire connector with silicone grease with a small screwdriver, and install wires. Connect distributor wiring harness. (Scheme 7): 2.9L Engine Lower Intake Manifold Tightening Sequence
4. Install upper intake manifold assembly. Connect vacuum hoses and electrical leads disconnected during removal. Install and adjust throttle linkage.
5. Connect hoses to radiator and by-pass hose from thermostat housing rear cover to intake manifold. Refill and bleed cooling system. Connect negative battery cable. Check ignition timing and engine idle speed. Check engine for leaks.

1. Drain engine coolant. Disconnect negative battery cable. Remove air throttle body. See «AIR INTAKE THROTTLE BODY R & I»(/ford/bronco-ii/i-1984-1990/remont/testing-diagnostics/#fuel-injection-system-multi-point) in this article. Remove fuel cap to relieve fuel tank pressure.
2. Remove pressure relief valve cap. Using EFI Pressure Gauge (T80L-9974-A), relieve fuel system pressure at fuel pressure relief valve (on fuel rail assembly).
3. Disconnect fuel supply and return lines. See «PUSH-CONNECT FITTINGS R & I»(/ford/bronco-ii/i-1984-1990/remont/testing-diagnostics/#fuel-injection-system-multi-point) in this article. Remove fuel injector wiring harness from engine. Disconnect upper radiator hose. Disconnect heater hose from engine.
4. Mark and remove distributor assembly. Remove rocker arm covers. Remove intake manifold attaching bolts and studs. Remove intake manifold with fuel rails and injectors in place. Remove side gaskets and end seals.

Scheme 8

1. Ensure intake manifold, cylinder head, and engine block mating surfaces are clean. Apply Silicone Sealer (D6AZ-19562-A) to intersection of engine block and head assembly at each of the 4 corners.
2. Install intake manifold end seals and secure in place. Position intake manifold side gaskets in place and insert locking tabs over tabs on cylinder head gaskets.
3. Apply Silicone Sealer (D6AZ-19562-A) over gasket in same places as in step 1. Carefully lower intake manifold into position to prevent smearing silicone sealer. Tighten intake manifold bolts in sequence. (Scheme 8)
4. Install thermostat housing and new gasket. Connect PCV line at PCV valve and exhaust manifold. Connect electrical leads and vacuum hoses. Apply silicone sealer to split between head and intake manifold (4 places).
5. Install rocker arm covers. Connect heater tube hose to heater elbow. Connect coolant by-pass hose. Connect radiator upper hose. Connect fuel lines at fuel charging assembly.
6. Install air cleaner outlet tube. Fill and bleed cooling system. Connect negative battery cable. Start engine and check for leaks. Check and adjust engine idle speed, transmission throttle linkage (overdrive transmission only) and cruise control. (Scheme 8): 3.0L Engine Lower Intake Manifold Tightening Sequence

1. Disconnect inlet air hose at crankcase filter cap. Remove throttle body inlet hoses. Remove upper intake manifold and throttle body assembly. See «UPPER INTAKE MANIFOLD & THROTTLE BODY ASSEMBLY R & I»(/ford/bronco-ii/i-1984-1990/remont/testing-diagnostics/#fuel-injection-system-multi-point) in this article.
2. Disconnect all vacuum hoses. Disconnect inlet pipe from exhaust manifolds. Disconnect power brake unit vacuum hose (if equipped). Remove bolts attaching manifolds to cylinder head. Remove manifolds and discard gaskets.

Clean and inspect manifold mounting surfaces. Position new gaskets and install manifolds. Tighten manifold bolts in sequence. (Scheme 9) To complete installation, reverse removal procedure.

4.9L Engine Lower Intake Manifold Tightening Sequence. Scheme 9

1. Remove air cleaner. Remove upper intake manifold and throttle body assembly. See «UPPER INTAKE MANIFOLD & THROTTLE BODY ASSEMBLY R & I»(/ford/bronco-ii/i-1984-1990/remont/testing-diagnostics/#fuel-injection-system-multi-point) in this article. Drain cooling system. Index mark position of distributor. Remove distributor, cap and wires.
2. Disconnect electrical leads at Engine Coolant Temperature (ECT) sensor, temperature sending unit, Air Charge Temperature (ACT) sensor, knock sensor, Electrical Vacuum Regulator (EVR), and thermactor air injection solenoids.
3. Disconnect injector wiring harness from main engine harness. Remove Exhaust Gas Oxygen (EGO) sensor ground wire from intake manifold. Remove fuel tank cap. Locate and disconnect electrical lead at fuel pump relay, inertia switch, or in-line high pressure fuel pump.
4. Crank engine for 10 seconds. If engine starts, crank engine an additional 5 seconds after engine stalls. Reconnect electrical lead that was disconnected in step 3. Disconnect negative battery cable.
5. Disconnect fuel supply and fuel return lines from fuel rails. See «PUSH-CONNECT FITTINGS R & I»(/ford/bronco-ii/i-1984-1990/remont/testing-diagnostics/#fuel-injection-system-multi-point) in this article. Remove upper radiator hose from thermostat housing.
6. Remove coolant by-pass hose. Remove heater outlet hose at intake manifold. Remove air cleaner bracket. Remove coil bracket nut and move bracket aside. Remove lower intake manifold assembly.

1. Clean and inspect manifold mounting surfaces. Apply Silicone Sealer (D6AZ-19562-A) to end seal joints. (Scheme 10) Position new gaskets, and install locator pins in opposite corners of manifold.
2. Lower manifold into position. Tighten intake manifold studs and bolts, in sequence. (Scheme 10) After 10 minutes, retighten bolts and studs. To complete installation, reverse removal procedure.
3. Check for damaged crossover fuel hose garter spring and "O" rings. Replacement garter spring and "O" rings are available in Coupler Rebuild Kit (E35Y-1D690-A). Wipe end of crossover lines with clean cloth. Install new "O" rings onto tube.
4. Lubricate ends of lines with clean refrigerant oil. To complete assembly, push fitting together with a slight twisting motion. Ensure garter spring is over flared end of female fitting. To complete installation, reverse removal procedure.

5.0L Eng Gasket Sealant App & Intake Manifold Tightening Seq. Scheme 10

Removal & Installation (1/4" Straight Fittings)

1. Inspect visible internal portion of fitting for dirt accumulation. If dirty, fitting must be cleaned prior to removal. Slowly twist fitting on tube and then push and pull fitting until it moves freely on tube.
2. Align jaws of 6-inch channel lock pliers with openings in side of fitting case, and compress portion of clip that retains fitting in case. (Scheme 11) Pull fitting from tube. If clip has been properly disengaged, fitting can be pulled from tube with little effort.
3. Inspect fitting and tube for parts that may have been disconnected from fitting during removal. Install new replacement clip into fitting body by inserting one serrated edge in first, then push other edges inward, into place. A "click" will be heard when clip is properly installed.
4. Wipe end of tube with clean cloth. Push fitting straight onto tube end. When fitting is properly engaged, a "click" will be heard. Pull on tube to ensure that fitting is fully engaged.

Removal & Installation (3/8" Straight & 5/16" Elbow Fittings)

1. Inspect visible internal portion of fitting for dirt accumulation. If dirty, fitting must be cleaned prior to removal. Slowly twist fitting on tube and then push and pull fitting until it moves freely on tube.
2. Remove hairpin clip from fitting by bending shipping tab downward until it clears body. Next, separate 2 clip legs (about 1/8" each) to disengage body, and then push legs into fitting. (Scheme 11)
3. Lightly pull clip from triangle end, and work clip free of tube and fitting. Grasp fitting and hose assembly, and pull straight apart. Inspect fitting and tube for parts that may have been disconnected from fitting during removal.
4. To install, insert new clip into any 2 adjacent openings, with triangular portion pointing away from fitting opening. Install clip fully. Legs of clip must be locked on outside of body.
5. Wipe tube end with clean cloth. Ensure fitting is clear of dirt and obstructions. Push fitting straight onto tube end. When fitting is properly engaged, a "click" will be heard. Pull on tube to ensure that fitting is fully engaged.

Exploded View of Quick Disconnect Fittings. Scheme 11

Removal & Installation (3/8", 1/2" & 5/8" Spring-Type Coupling)

1. Relieve fuel system pressure. Place indicated spring lock coupler over coupling. See «SPRING LOCK COUPLER IDENTIFICATION»(/ford/bronco-ii/i-1984-1990/remont/testing-diagnostics/#fuel-injection-system-multi-point) table. Push coupler along tube, and into coupling, to release female fitting from garter spring.
2. Pull spring lock coupling apart. Remove coupler from disconnected spring lock coupling. (Scheme 12) Check for damaged garter spring and "O" rings. Wipe end of lines with clean cloth.
3. To install, place new "O" rings onto tube. Lubricate ends of lines with clean refrigerant oil. Locate White indicator ring which may have slipped down length of tube. Insert White indicator ring into cage of male fitting.
4. Push fitting together with a slight twisting motion. The White indicator ring should pop free of cage to indicate that male fitting is properly seated over flared end of female fitting.

SPRING LOCK COUPLER IDENTIFICATION

SPRING LOCK COUPLER IDENTIFICATION

Scheme 12

1. Remove throttle linkage shield, throttle cable, and cruise control cable. Disconnect throttle position sensor wiring. Remove air intake, by-pass, and crankcase vent hoses.
2. Remove throttle body nuts/bolts. Carefully separate throttle body from upper intake manifold. Clean gasket surfaces, but do not allow gasket material to fall into upper intake manifold. To install, reverse removal procedure.

1. Disconnect throttle position sensor connector. Remove air inlet duct. Remove snow/ice shield and disconnect throttle cable from ball stud.
2. Disconnect air by-pass hose, PCV closure hose, and canister purge hose from fittings beneath throttle body. Remove 4 screws and throttle body from upper intake manifold.
3. Remove and discard gasket between throttle body and upper intake manifold. Clean throttle body and upper intake manifold gasket surfaces. To install, reverse removal procedure.

1. Disconnect electrical leads at air by-pass valve and throttle position sensor. Disconnect throttle linkage shield, throttle linkage, and cruise control cable. Disconnect air inlet hoses from air throttle body.
2. Disconnect fuel evaporative hoses from purge ports of air throttle body. Remove 4 air throttle body nuts. Carefully remove air throttle body from upper intake manifold. Remove and discard gasket. To install, reverse removal procedure.

1. Disconnect electrical leads from throttle position sensor and air by-pass valve. Remove 4 air throttle body bolts. Carefully separate air throttle body from upper intake manifold.
2. Remove and discard gasket between air throttle body and upper intake manifold. Clean gasket surface, but do not allow gasket material to fall into upper intake manifold. To install, reverse removal procedure.

1. Open hood and install protective covers. Ensure ignition key is in the "OFF" position. Disconnect negative battery cable. Remove air inlet tube from air cleaner to throttle body.
2. Remove fuel cap to relieve tank pressure. Disconnect vacuum hose from fuel pressure regulator. Using hand-held vacuum pump, apply about 25 in. Hg pressure to pressure regulator. Fuel pressure will be released through fuel return hose.
3. Remove vacuum hose at pressure regulator. Remove screws from regulator housing. Remove pressure regulator, "O" ring, and washer.

1. Lubricate "O" ring with a light oil. DO NOT use silicone grease. Ensure regulator and manifold gasket surfaces are clean and dry. Install new washer and "O" ring on regulator.
2. Install regulator on manifold and tighten retaining screws. Install vacuum hose. Install fuel filler cap. Turn ignition on and off several times without starting engine to pressurize fuel system. Check fuel injection system for leaks at fuel rails, fittings, and injectors.

1. Open hood and install protective covers. Remove fuel tank cap. Locate and disconnect electrical lead at fuel pump relay, inertia switch, or in-line high pressure fuel pump.
2. Crank engine for 10 seconds. If engine starts, crank engine an additional 5 seconds after engine stalls. Reconnect electrical lead that was disconnected in step 1). Disconnect negative battery cable.
3. Remove vacuum hose from fuel pressure regulator. Remove Allen head screws from fuel pressure regulator housing. Remove fuel pressure regulator, gasket, and "O" ring.

Lubricate "O" ring with a light oil. DO NOT use silicone grease. Ensure regulator and manifold gasket surfaces are clean and dry. Install regulator on manifold. Tighten retaining screws. Install vacuum line.

Removal (All Others)

1. Remove fuel tank cap and pressure relief valve cap. Install EFI Pressure Gauge (T80L-9974-A) at pressure relief valve to depressurize fuel system.
2. Remove vacuum hose at fuel pressure regulator. Remove screws from regulator housing. Remove pressure regulator, gasket, and "O" ring.

Installation (All Others)

Lubricate "O" ring with a light oil. DO NOT use silicone grease. Ensure regulator and manifold gasket surfaces are clean and dry. Install regulator on manifold. Tighten retaining screws. Install vacuum line.

1. Open hood and install protective covers. Ensure ignition key is in the "OFF" position. Disconnect negative battery cable. Remove air inlet tube from air cleaner to throttle body.
2. Remove fuel cap to relieve tank pressure. Disconnect vacuum hose from fuel pressure regulator. Using hand-held vacuum pump, apply about 25 in. Hg pressure to pressure regulator. Fuel pressure will be released through fuel return hose.
3. Remove upper intake manifold and throttle body assembly. See «UPPER INTAKE MANIFOLD & THROTTLE BODY ASSEMBLY R & I»(/ford/bronco-ii/i-1984-1990/remont/testing-diagnostics/#fuel-injection-system-multi-point) in this article. Remove fuel supply manifold. See «FUEL SUPPLY MANIFOLD ASSEMBLY R & I»(/ford/bronco-ii/i-1984-1990/remont/testing-diagnostics/#fuel-injection-system-multi-point) in this article.
4. Carefully remove wiring harness from injector(s) as required. Remove injector retaining clips(s). Remove injectors from fuel supply manifold by using a slight twisting/pulling motion.

Lubricate new injector "O" rings with a light oil. DO NOT use silicone grease. To complete installation, reverse removal procedure.

1. Open hood and install protective covers. Ensure ignition key is in the "OFF" position. Disconnect negative battery cable. Remove fuel cap to relieve tank pressure.
2. Install EFI Pressure Gauge (T80L-9974-A) at pressure relief valve to depressurize fuel system. Remove upper intake manifold and throttle body assembly. See «UPPER INTAKE MANIFOLD & THROTTLE BODY ASSEMBLY R & I»(/ford/bronco-ii/i-1984-1990/remont/testing-diagnostics/#fuel-injection-system-multi-point) in this article.
3. Remove fuel supply manifold. See «FUEL SUPPLY MANIFOLD ASSEMBLY R & I»(/ford/bronco-ii/i-1984-1990/remont/testing-diagnostics/#fuel-injection-system-multi-point) in this article. Carefully remove wiring harness from injector(s) as required. Remove injectors from fuel supply manifold by using a slight twisting/pulling motion.

Lubricate new injector "O" rings with a light oil. DO NOT use silicone grease. To complete installation, reverse removal procedure.

1. Open hood and install protective covers. Remove fuel tank cap. Locate and disconnect electrical lead at fuel pump relay, inertia switch, or in-line high pressure fuel pump.
2. Crank engine for 10 seconds. If engine starts, crank engine an additional 5 seconds after engine stalls. Reconnect electrical lead that was disconnected in step 1. Disconnect negative battery cable.
3. Remove upper intake manifold assembly. See «UPPER INTAKE MANIFOLD & THROTTLE BODY ASSEMBLY R & I»(/ford/bronco-ii/i-1984-1990/remont/testing-diagnostics/#fuel-injection-system-multi-point) in this article. Carefully disconnect electrical lead(s) from injector(s). Remove injector(s) from fuel supply manifold by using a slight twisting/pulling motion.

Lubricate new injector "O" rings with a light oil. DO NOT use silicone grease. To complete installation, reverse removal procedure.

1. Remove fuel tank cap and pressure relief valve cap. Install EFI Pressure Gauge (T80L-9974-A) at pressure relief valve to depressurize fuel system.
2. Disconnect wiring harness from each injector. Remove fuel supply manifold. See «FUEL SUPPLY MANIFOLD ASSEMBLY R & I»(/ford/bronco-ii/i-1984-1990/remont/testing-diagnostics/#fuel-injection-system-multi-point) in this article. Remove injectors from fuel supply manifold by using a slight twisting/ pulling motion.

Lubricate new injector "O" rings with a light oil. DO NOT use silicone grease. To complete installation, reverse removal procedure.

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

See also:
• UPPER INTAKE MANIFOLD & THROTTLE BODY ASSEMBLY R & I