Engine Controls - Remove/install/overhaul Buick Electra Park Avenue

INTRODUCTION

Removal, overhaul and installation procedures (when given by manufacturer) are covered in this article. If component removal and installation is primarily an unbolt and bolt on procedure, only a simple torque specification may be supplied.

FUEL SYSTEM (CARBURETOR)

The Rochester E4MC carburetor is used only on the 5.0L (VIN Y) engines. Carburetor number is stamped vertically on float bowl, near secondary throttle. (Scheme 1) This number must be used for ordering replacement components and performing adjustments. Carburetor identification number must be transferred onto new float bowl if float bowl is replaced.

These carburetors are equipped with a computer control feedback system. This is indicated by the first letter "E" of identification number. The last letter of identification number indicates type of choke used. Letter "C" indicates a hot air type choke.

Scheme 1

ON-VEHICLE ADJUSTMENTS

Note. For all on-vehicle adjustments, see ON-VEHICLE ADJUSTMENTS article.

ELECTRONIC CONTROL MODULE (ECM)

STATIC CHARGE

Scheme 2

Note. Prior to replacement of ECM, a careful inspection of all wiring and control components should be made. Failure to test for shorts, grounds and reasons for Quad-Driver failure may cause repeat failure of ECM. To prevent internal damage to ECM, ignition switch must be in OFF position when disconnecting or reconnecting ECM connectors or 12-volt components.

Removal

Turn ignition switch to OFF position. Disconnect negative battery cable. Remove electrical connectors from ECM. Remove ECM from vehicle. Remove MEM-CAL or PROM and CALPAC (if equipped) from ECM.

Installation

Install PROM and CALPAC (if equipped) or MEM-CAL in new ECM. Reinstall ECM into vehicle. Reconnect electrical connectors to ECM. Install access panels. Reconnect negative battery cable to battery.

Removal & Installation

Some ECM models use a CALPAC as well as a PROM. (Scheme 3) The CALPAC must also be removed from replaced ECM and installed in new one. Removal and replacement procedures for CALPAC are same as for PROM. See Programmable Read-Only Memory (PROM) in this article. If units are installed improperly, grounding diagnostic test lead will set Code 52.

Scheme 3

Disconnect negative battery cable. Remove ECM from vehicle. Using 2 fingers, push retaining clips back from MEM-CAL. At same time, grasp it at both ends and lift up out of socket. DO NOT remove MEM-CAL cover.

1. Carefully align MEM-CAL pins with ECM pin holes. DO NOT press in middle of MEM-CAL. Push downward evenly on ends of MEM-CAL until retaining clips on ends of MEM-CAL snap into place.
2. Install ECM. Reconnect negative battery cable. Turn ignition on and ground ALDL connector. Code 12 should flash at least 4 times (if not other codes are present). If code(s) 42, 43, 51 or 52 is present, or if CHECK ENGINE light stays on constantly with code(s) present, MEM-CAL is not fully seated or defective. If it is necessary to remove MEM-CAL, follow previous removal instructions.

1. Remove ECM from vehicle as previously described. Position ECM so that bottom cover is facing upward. Remove slide-off PROM access cover by depressing locking tab.
2. Using PROM removal tool, grasp PROM at narrow ends. Gently rock PROM from end to end while pulling up. If new PROM is to be installed, remove old PROM from PROM carrier.

Note. Note reference notch locations in PROM, carrier and ECM for reassembly reference.

1. Ensure new PROM has same service number as old one. Place new PROM in PROM carrier. Position squarely over ECM PROM socket. Press on PROM carrier until PROM is firmly seated in ECM. NOTE: Ensure reference notches in both ECM and PROM are properly aligned. If PROM is installed backwards and key is turned on, PROM will be destroyed.
2. Reinstall PROM access cover on ECM. Reinstall ECM in vehicle as previously described. Start engine and ground ALDL diagnostic test connector. Watch for trouble Code 51 or 52.
3. If this occurs, PROM is not fully seated in ECM, installed backwards, has bent pins or is defective. If pins are bent and crack when straightened, PROM must be replaced. If PROM is installed backwards or is defective, it must be replaced.

ELECTRONIC SPARK CONTROL (ESC) MODULE

Note. The ESC is located on a bracket behind the distributor, mounted to firewall.

Turn ignition off. Remove screws holding bracket to firewall. Rotate bracket to access ESC module. Disconnect ESC module harness connector. Remove ESC mounting screws and remove ESC. To install, reverse removal procedure.

1. Relieve fuel pressure. See FUEL PRESSURE RELIEF under FUEL SYSTEM (PFI) in this article. Remove air inlet ducts. Disconnect and mark electrical connections and vacuum hoses from throttle body. Disconnect control cables from throttle body.
2. Drain cooling system. Remove coolant hoses. Remove throttle body retaining bolts. Remove throttle body and gasket.

Note. Identification number is stamped on throttle body near coolant cover. Identification number must be used for ordering replacement components.

1. To install, reverse removal procedure using new gasket. Tighten retaining bolts to specification. See «TORQUE SPECIFICATIONS»(/buick/electra-park-avenue/1990-1990/remont/removal-installation/#engine-controls-removeinstalloverhaul__torque-specifications) at end of article. Fill cooling system.
2. If a new Idle Air Control (IAC) is being installed, ensure proper IAC pintle length setting prior to installation. See appropriate IDLE AIR CONTROL VALVE under «REMOVAL & INSTALLATION»(/buick/electra-park-avenue/1990-1990/remont/removal-installation/#engine-controls-removeinstalloverhaul__removal-installation) in this article. Adjust idle speed and TPS (if removed). See «ON-VEHICLE ADJUSTMENTS»(/buick/electra-park-avenue/1990-1990/remont/removal-installation/#engine-controls-removeinstalloverhaul__on-vehicle-adjustments) .

Removal (2.0L, 2.3L, 3.3L, 3.8L & 4.5L)

1. Relieve fuel pressure. See FUEL PRESSURE RELIEF under «FUEL SYSTEM (PFI)»(/buick/electra-park-avenue/1990-1990/remont/removal-installation/#engine-controls-removeinstalloverhaul) in this article. Disconnect pressure regulator-to-fuel rail hose. On 2.3L, remove fuel rail. See «FUEL RAIL & INJECTORS»(/buick/electra-park-avenue/1990-1990/remont/removal-installation/#engine-controls-removeinstalloverhaul__fuel-rail-injectors) in this article.
2. On all models, remove pressure regulator retaining bolts. Remove pressure regulator from fuel rail. On 2.3L, remove pressure regulator retainer and seal from fuel rail.

Installation (2.0L, 2.3L, 3.3L, 3.8L & 4.5L)

To install, reverse removal procedures. Lubricate fuel rail seal with oil and install in regulator. Tighten bolts to specification. See TORQUE SPECIFICATIONS at end of article.

Removal (3.1L)

1. Relieve fuel pressure. See FUEL PRESSURE RELIEF under «FUEL SYSTEM (PFI)»(/buick/electra-park-avenue/1990-1990/remont/removal-installation/#engine-controls-removeinstalloverhaul) in this article. Remove fuel rails. See «FUEL RAIL & INJECTORS»(/buick/electra-park-avenue/1990-1990/remont/removal-installation/#engine-controls-removeinstalloverhaul__fuel-rail-injectors) in this article.
2. Remove inlet and return fuel fittings and gaskets. Remove pressure regulator-to-bracket retaining bolts. Separate fuel rails from pressure regulator.
3. Remove pressure regulator base-to-fuel rail connector tubes from pressure regulator.

Installation (3.1L)

1. To install, reverse removal procedures. Lubricate new "O" rings with oil. Install fuel return "O" rings on fuel rails. Return "O" rings are larger in diameter than connector tube "O" rings.
2. Tighten bolts to specification. See «TORQUE SPECIFICATIONS»(/buick/electra-park-avenue/1990-1990/remont/removal-installation/#engine-controls-removeinstalloverhaul__torque-specifications) at end of article.

Removal (5.0L & 5.7L)

1. Relieve fuel pressure. See FUEL PRESSURE RELIEF under «FUEL SYSTEM (PFI)»(/buick/electra-park-avenue/1990-1990/remont/removal-installation/#engine-controls-removeinstalloverhaul) in this article. Remove fuel rails. See «FUEL RAIL & INJECTORS»(/buick/electra-park-avenue/1990-1990/remont/removal-installation/#engine-controls-removeinstalloverhaul__fuel-rail-injectors) in this article.
2. Remove front crossover tube retainer on right fuel rail. Remove rear crossover tube retainer at pressure regulator on right fuel rail. Separate fuel rail assemblies.
3. Remove pressure regulator bracket-to-fuel rail bolt. Remove bracket to regulator base bolt. Remove bracket. Remove fuel outlet tube-to-right fuel rail bolt. Remove base-to-right fuel rail bolt.
4. Remove pressure regulator assembly from fuel rail. Rotate pressure regulator and remove from outlet tube. Remove base-to-fuel rail connector tube. Remove "O" rings from connector tube, outlet tube, and crossover tubes.

Installation (5.0L & 5.7L)

To install, reverse removal procedures. Install new "O" rings and lubricate with oil. Tighten retaining bolts to specification. See TORQUE SPECIFICATIONS at end of article.

FUEL RAIL & INJECTORS

Removal (2.0L, 3.3L, 3.8L & 4.5L)

1. Relieve fuel pressure. See FUEL PRESSURE RELIEF under «FUEL SYSTEM (PFI)»(/buick/electra-park-avenue/1990-1990/remont/removal-installation/#engine-controls-removeinstalloverhaul) in this article. Turn ignition off. Disconnect negative battery cable. Disconnect wiring connectors from injectors. Disconnect and plug hoses to fuel rail.
2. On 4.5L, remove power steering pump and move to side. On all models, remove fuel rail retaining bolts. Remove injector-to-fuel rail retaining clip (if used). Separate fuel rail from injectors. Remove injectors. (Scheme 4)

Scheme 4

Scheme 5

Note. If injector is replaced, ensure replacement injector has the same part number as that removed.

Installation (2.0L, 3.3L, 3.8L & 4.5L)

To install, reverse removal procedure. Coat new "O" rings with oil. Install "O" rings on injectors. Tighten fuel rail retaining bolts to specification. See TORQUE SPECIFICATIONS at end of article.

Removal (2.3L)

1. Relieve fuel pressure. See FUEL PRESSURE RELIEF under «FUEL SYSTEM (PFI)»(/buick/electra-park-avenue/1990-1990/remont/removal-installation/#engine-controls-removeinstalloverhaul) in this article. Remove crankcase ventilation oil/separator.
2. Remove fuel lines from fuel rail. Remove vacuum line at pressure regulator. Disconnect wiring connector while pushing inward on connector. Remove fuel rail retaining bolts. Remove fuel rail. (Scheme 6)
3. Remove injector-to-fuel rail retaining clip. Remove injector from fuel rail. Remove injector "O" rings.

Scheme 6

Installation (2.3L)

To install reverse removal procedure. Lubricate injector "O" rings with oil. Install injector-to-fuel rail retaining clip with open end facing injector electrical connection. Tighten fuel rail retaining bolts.

Scheme 7

1. Relieve fuel pressure. See FUEL PRESSURE RELIEF under «FUEL SYSTEM (PFI)»(/buick/electra-park-avenue/1990-1990/remont/removal-installation/#engine-controls-removeinstalloverhaul) in this article. Disconnect negative battery cable. Remove intake manifold upper plenum. Disconnect and mark vacuum lines. Remove EGR-to-intake manifold retaining bolts. Some models use an EGR pipe which requires removal at EGR base.
2. Remove throttle cable bracket bolts. Disconnect cables and electrical wiring connections from throttle body. Remove throttle body from intake manifold. Remove plenum and gasket. (Scheme 7)
3. Disconnect vacuum hose to pressure regulator. Relieve fuel pressure. Remove runners. Disconnect fuel lines from fuel rail. With ignition off, disconnect electrical connections from injectors.
4. Remove fuel rail retaining bolts. Remove fuel rail and injectors. On 5.0L and 5.7L, rotate injector retaining clip to unlock position.
5. On all models, remove injectors from fuel rail. Remove "O" rings from injectors.

Installation (3.1, 5.0L & 5.7L)

To install, reverse removal procedure. Coat new "O" rings with oil. Install "O" rings on injectors. Tighten bolts to specification. See TORQUE SPECIFICATIONS at end of article.

Remove air cleaner. Disconnect electrical connector. Remove retaining screws and Idle Speed Control (ISC). To install, reverse removal procedure. To adjust ISC minimum and maximum authority, see ON-VEHICLE ADJUSTMENTS article in this section.

Note. The ISC motor is factory calibrated and should not be disassembled. Replace as complete assembly only. DO NOT soak ISC motor in carburetor cleaner.

IDLE AIR CONTROL (IAC) VALVE (PFI)

Remove electrical connector from IAC valve. Remove IAC valve and gasket or "O" ring. IAC valve screws into housing on 2.0L, 5.0L and 5.7L vehicles. Retaining screws are used on 2.3L, 3.1L, 3.3L and 3.8L vehicles.

1. The extended distance of a new IAC must be checked prior to installation. Damage will occur if measurement is incorrect. Distance must not exceed 1 1/8" (28 mm). Measurement should be taken from valve housing flange to end of cone. DO NOT extend or retract pintle on IAC valve which has been in service or damage to internal worm drive may occur.
2. To retract pintle on new IAC (except 2.0L models), slowly exert finger pressure on valve. On 2.0L models, identify IAC valve as being either a type I or type II valve. Type I IAC valve has a collar around the connector end of IAC valve. (Scheme 8)
3. To retract type I IAC valve, exert firm pressure on plunger (a slight side-to-side movement may be helpful). To retract plunger on type II IAC valve, compress retaining spring from valve while turning valve inward with a clockwise motion. Return spring to original position with straight portion of spring end aligned with flat surface of valve.
4. Install new "O" ring or gasket on valve. Coat "O" ring with oil. Install IAC valve. Tighten IAC valve to specifications. See «TORQUE SPECIFICATIONS»(/buick/electra-park-avenue/1990-1990/remont/removal-installation/#engine-controls-removeinstalloverhaul__torque-specifications) at end of article.
5. Install electrical connector. The IAC resets when ignition switch is turned from the "ON" to the "OFF" position (at speeds greater than 35 MPH on 2.0L). On some models it may be necessary to shift transmission into Drive (auto. trans.) or Neutral (man. trans.) before learning process is complete.

Scheme 8

THROTTLE BODY

An 8-digit unit identification number is stamped on throttle body assembly. On model 220, number is stamped vertically on front of throttle body at Throttle Position Sensor (TPS) side. On model 700, number can be found on TPS side of mounting flange. Letter codes are stamped on throttle body at external tube locations to identify vacuum hose connections.

1. Relieve fuel pressure. See FUEL PRESSURE RELIEF under «FUEL SYSTEM (TBI)»(/buick/electra-park-avenue/1990-1990/remont/removal-installation/#engine-controls-removeinstalloverhaul) in this article. Disconnect negative battery cable. Remove air cleaner and related ducting.
2. Remove electrical connectors from IAC, TPS and fuel injector(s). Lay wiring harness aside. Remove throttle cable, return springs, transmission/transaxle cable, and cruise control cable (if equipped). Label and remove vacuum hoses.
3. Remove fuel feed and return lines. Use 2 wrenches to prevent fuel nuts in throttle body from loosening. Remove fuel line "O" rings and discard. Remove throttle body retaining bolts. Remove TBI unit and base gasket. Discard base gasket.

1. Using new base gasket, install throttle body unit to intake manifold. Tighten retaining bolts to specification. See «TORQUE SPECIFICATIONS»(/buick/electra-park-avenue/1990-1990/remont/removal-installation/#engine-controls-removeinstalloverhaul__torque-specifications) at end of article. Install new "O" rings onto fuel lines.
2. Connect fuel feed and return lines to throttle body. Use a back-up wrench to prevent fuel line fittings in throttle body from turning. Tighten fuel line nuts to specification. See «TORQUE SPECIFICATIONS»(/buick/electra-park-avenue/1990-1990/remont/removal-installation/#engine-controls-removeinstalloverhaul__torque-specifications) at end of article. Install vacuum hoses and brackets. To complete installation, reverse removal procedure.

Removal (Model 220)

1. Relieve fuel pressure. See FUEL PRESSURE RELIEF under «FUEL SYSTEM (TBI)»(/buick/electra-park-avenue/1990-1990/remont/removal-installation/#engine-controls-removeinstalloverhaul) in this article. Remove throttle body cover and leave cover gasket in place. Using screwdriver and fulcrum, carefully pry injector out. (Scheme 9) Remove small "O" ring from nozzle end of injector.
2. Carefully rotate injector fuel filter back and forth to remove fuel filter from base of injector. Remove and discard throttle body cover gasket. Remove large "O" ring and steel back-up washer from top counterbore of throttle body injector cavity.

Installation (Model 220)

1. Install fuel filter on nozzle end of fuel injector. Large end of filter must face injector so that filter covers raised rib at base of injector. Lubricate small "O" ring with ATF and push "O" ring on nozzle end of injector until it presses against injector filter.
2. Install steel back-up washer in top counterbore of throttle body injector cavity. Lubricate large "O" ring with ATF and install "O" ring directly over back-up washer. (Scheme 31) Ensure that "O" ring is seated properly in cavity and is flush with top of throttle body casting. CAUTION: Back-up washer and large "O" ring must be installed before injector. Improper seating of "O" ring will cause fuel leak.
3. Install "O" ring on injector. Install injector into cavity by aligning raised lug on injector base with cast-in notch of throttle body cavity. Push down on injector until fully seated. Electrical terminals of injector will be approximately parallel with throttle shaft. Install throttle body cover.

Removal (Model 700)

Relieve fuel pressure. See FUEL PRESSURE RELIEF under FUEL SYSTEM (TBI) in this article. Remove fuel injector retainer screw and retainer. Using screwdriver and fulcrum on side of injector opposite connector terminals, carefully pry injector out. (Scheme 9) Remove upper and lower "O" rings and discard.

Scheme 9

Installation (Model 700)

1. Lubricate new upper and lower "O" rings with engine oil and place them on injector. Ensure upper ring is in groove and lower ring is flush against filter.
2. Position injector in fuel meter assembly with electrical connector facing cutout for wire grommet.
3. Push injector down to seat in cavity. Install injector retainer. Coat injector retainer screw with thread locking compound and install. Tighten screw to 27 INCH lbs. (3.0 N.m).

Remove air cleaner and related ducting. Remove Idle Air Control (IAC) electrical connector. On model 220, unscrew IAC valve. On model 700, remove IAC retaining screws and remove IAC valve. Replace as necessary.

1. Inspect gasket or "O" ring for damage. Replace as necessary. Measure distance from IAC contact flange to tip of pintle. Distance should not exceed 1 1/8" (28 mm). If valve is extended too far, damage to valve will result during installation.
2. To set IAC pintle length on a new IAC, use finger pressure to slowly retract pintle. Lubricate new "O" ring with ATF and install new gasket. Install IAC valve on throttle body. Tighten IAC valve to specification. See «TORQUE SPECIFICATIONS»(/buick/electra-park-avenue/1990-1990/remont/removal-installation/#engine-controls-removeinstalloverhaul__torque-specifications) at end of article. CAUTION: DO NOT extend or retract pintle if IAC valve has been in service or damage to worm gear will result.
3. Connect electrical lead to IAC valve and install air cleaner. Start engine and allow it to reach normal operating temperature. Drive vehicle at least 43 MPH to allow ECM to reset idle speed. It may be necessary to cycle ignition off and restart vehicle before proper idle will be initialized.

Removal (Camaro & Firebird)

1. Relieve fuel system pressure. Disconnect battery negative terminal. Raise car on hoist. Drain fuel from fuel tank. Disconnect exhaust pipe at converter and rear hanger. Allow exhaust to hang over axle assembly.
2. Remove tailpipe and muffler heat shields. Remove fuel filler neck shield behind left rear tire. Remove rear suspension track bar and brace. Disconnect harness connector to fuel pump assembly.
3. Disconnect all fuel lines. Remove fuel line retaining bracket on left side and remove brake line clip from bracket.
4. Position support jack under axle assembly. Disconnect lower ends of shock absorbers. Disconnect rear stabilizer bar from frame (if equipped).
5. On models equipped with 2-piece driveshaft, remove center support bearing-to-rear axle torque arm bolts. On all models, remove rear axle torque arm-to-differential housing bolts/nuts. Wire end of rear axle torque arm aside. Remove driveshaft-to-differential yoke bolts/screws. Wire end of driveshaft aside.
6. Lower rear suspension as far as possible without damaging brake lines and cables and remove both coil springs. Remove tank straps bolts. Remove fuel tank by rotating front of tank down and sliding to the right. Remove fuel pump assembly from fuel tank.

Removal (Corvette)

1. Relieve fuel system pressure. Remove fuse marked "Fuel Pump" from fuse block in passenger compartment. Crank engine. Engine will start and run until fuel in line is exhausted. When engine stops, engage starter again for 3 seconds to ensure engine will not start.
2. Remove battery ground cable. Remove fuel cap, fuel tank filler door. Remove filler neck housing and disconnect drain hose. Remove screws attaching fuel meter and pump assembly to tank. Disconnect fuel hoses, vapor hose and electrical connector from fuel meter and pump assembly. Pull pump up into pulsator while pulling outward away from bottom support. Remove pump.

Removal (Except Camaro, Corvette & Firebird)

1. Disconnect negative battery cable. Relieve fuel pressure. Relieve fuel pressure. See «FUEL PRESSURE RELIEF»(/buick/electra-park-avenue/1990-1990/remont/removal-installation/#engine-controls-removeinstalloverhaul) under FUEL SYSTEM (TBI) or «FUEL PRESSURE RELIEF»(/buick/electra-park-avenue/1990-1990/remont/removal-installation/#engine-controls-removeinstalloverhaul__fuel-pressure-relief) under FUEL SYSTEM (PFI). Remove filler neck. Lower fuel tank. Disconnect fuel lines and electrical connection.
2. Remove fuel level sending unit and pump retaining bolts or cam lock ring. Lift assembly from fuel tank and remove fuel pump from sending unit.
3. Pull fuel pump upward while pulling outward away from bottom support. Use care not to damage rubber insulator and strainer.

To install, reverse removal procedure using new "O" ring/gasket.

Removal & Installation (2.2L, 2.5L & 3.1L)

1. Disconnect negative battery cable. Unplug connectors at ignition module. Disconnect spark plug wires from coil pack. Remove ignition module from engine block. Remove coils and assembly plate.
2. On 2.5L engines, inspect crankshaft sensor "O" ring for wear, cracks or other damage. Replace if necessary. Lubricate new "O" ring with engine oil before installing.
3. To install, reverse removal procedure. Tighten ignition coil nuts and module to specification. See «TORQUE SPECIFICATIONS»(/buick/electra-park-avenue/1990-1990/remont/removal-installation/#engine-controls-removeinstalloverhaul__torque-specifications) at the end of article.

Note. If spark plug boots adheres to spark plugs, use Boot Remover (J-36011). Twist first and then pull upward. Boots must be in place on housing prior to ignition system assembly installation or damage may result.

Removal & Installation (2.3L)

1. Disconnect negative battery cable. Disconnect 11-pin harness connector. Remove 4 ignition module cover-to-cam carrier bolts.
2. Remove ignition system assembly from engine. Remove 4 housing cover screws. Remove housing cover. Remove coil harness connector from module. Remove module-to-cover screws. Remove module from cover. To install, reverse removal procedure.

Note. DO NOT wipe grease from module or coil if module is not being replaced. If a new module is being installed, silicone grease will be included. Spread grease on metal face of module and on the cover where the module seats. This grease is necessary for module cooling purposes.

Scheme 10

Removal & Installation (3.3L & 3.8L)

Disconnect negative battery cable. Unplug 14-way connector at ignition module. Disconnect spark plug wires from coil pack. Remove nuts and washers securing ignition module to bracket. Remove coil-to-ignition module Torx screws. Note wire colors for reassembly. Unplug connectors between ignition coil and module. Remove module. To install, reverse removal procedure.

Removal (3.3L & 3.8L)

1. Remove serpentine belt from crankshaft pulley. Raise vehicle on hoist. Remove right front tire and wheel assembly. Remove right side lower engine compartment filler panel and right lower wheelwell-to-engine compartment bolt, if necessary.
2. Using 28-mm socket, remove crankshaft harmonic balancer retaining bolt. Remove harmonic balancer. Disconnect sensor harness connector. Remove sensor and pedestal (as an assembly) from block.

Installation (3.3L & 3.8L)

1. Loosen pinch bolt until sensor is free to slide in pedestal. Position sensor, with pedestal attached, onto Installer (J-37089). Position installer onto crankshaft. (Scheme 11)
2. Install pedestal-to-block bolts and pedestal pinch bolt. Tighten bolts. Remove installer. Place harmonic balancer onto installer. Rotate balancer on installer. If any vanes of interrupter rings contact installer, replace harmonic balancer.
3. Install balancer on crankshaft. To complete installation, reverse removal procedure. Tighten balancer retaining bolt to specification. See «TORQUE SPECIFICATIONS»(/buick/electra-park-avenue/1990-1990/remont/removal-installation/#engine-controls-removeinstalloverhaul__torque-specifications) at end of article.

Scheme 11

Removal & Installation (2.5L)

Remove DIS ignition module. Remove crankshaft sensor mounting screws and remove sensor from DIS module. Inspect "O" ring for wear, before installing DIS module. Replace if necessary. To install, reverse removal procedure. See TORQUE SPECIFICATIONS in this article.

Removal & Installation (2.0L, 2.3L & 3.1L)

1. Disconnect the negative battery cable. Remove serpentine belt from crankshaft. Raise and support vehicle. Remove right front tire and wheel assembly. Remove right inner fender access cover.
2. Using a 28mm socket, remove harmonic balancer retaining bolt. Remove harmonic balancer. Disconnect the crankshaft sensor electrical connector.
3. Remove the crankshaft sensor retaining and pinch bolts. (Scheme 12)or (Scheme 13). Remove the crankshaft sensor and mounting bracket as an assembly from engine block. Remove the crankshaft sensor from its mounting bracket.

1. Loosely install the crankshaft sensor onto its mounting bracket. Position the sensor/bracket assembly onto the Alignment Tool (J-37089). Position the Alignment Tool onto the crankshaft.
2. Install and tighten the crankshaft sensor retaining bolts to 22 Ft. Lbs. (30 N.m). Install and tighten the mounting bracket pinch bolt to 89 INCH Lbs. (10 N.m). Remove the Alignment Tool from the crankshaft sensor/bracket assembly. Place the Alignment Tool onto the harmonic balancer and turn the harmonic balancer.
3. If any vane of the harmonic balancer touches the Alignment tool, replace the balancer assembly. Install the balancer onto the crankshaft. Tighten the harmonic balancer retaining bolt to 219 Ft. Lbs. (298 N.m). Install inner fender shield.
4. Install the right front tire and wheel assembly. Tighten the lug nuts to 100 Ft. Lbs (140 N.m). Lower vehicle and install the serpentine belt.

Removing/Installing Crankshaft & Camshaft Sensors (2.0L, 2.3L, 3.3L & 3.8L). Scheme 12

Removing/Installing Crankshaft & Camshaft Sensors (3.1L). Scheme 13

Disconnect the negative battery cable. Remove water pump pulley retaining bolts. Remove serpentine belt. Remove water pump pulley. Remove the weather pack connector. Remove the camshaft sensor retaining bolt. (Scheme 12) Pull and twist the sensor to remove it from the engine front cover.

Lubricate the camshaft sensor "O" ring. Push and twist the camshaft sensor to install. Install the sensor retaining bolt, weather pack connector, water pump pulley, and serpentine belt. Tighten the camshaft sensor retaining bolt to 75 INCH Lbs. (8.5 N.m). Install and tighten the water pump pulley retaining bolts to 115 INCH Lbs. (13 N.m). Reconnect the negative battery cable.

Type II (3.3L)

Disconnect negative battery cable. Remove spark plug wires from coil. Remove bolts securing coil to module. Remove coil assembly. To install, reverse removal procedure. Tighten retaining bolts to specification. See TORQUE SPECIFICATIONS at end of article.

Type III (3.8L)

Disconnect negative battery cable. Remove spark plug wires from coil pack. Remove Torx screws securing coil to ignition module. Tilt coil assembly back. Disconnect module connectors and remove coil pack. To install, reverse removal procedure. Tighten retaining bolts to specifications. See TORQUE SPECIFICATIONS at end of article.

Removal & Installation (2.0L, 2.2L, 2.5L & 3.1L)

Disconnect negative battery cable. Remove spark plug wires from coils. Remove nuts or screws from ignition coils. Remove coils. To install, reverse removal procedure.

Disconnect negative battery cable. Disconnect 11-pin harness connector. Remove ignition cover-to-cam carrier bolts. Remove ignition system assembly from engine. Remove housing cover screws. Remove housing cover. Remove coil harness connector from module. Remove module-to-cover screws. Remove module from cover. To install, reverse removal procedures. See TORQUE SPECIFICATIONS in this article.

Disconnect electrical connection from TPS. Remove TPS retaining screws. Remove TPS.

1. With throttle valve in closed position, install TPS on throttle body. Ensure TPS lever engages with drive lever on throttle shaft. Install retaining screws and electrical connection.
2. The TPS on most models are self-zeroing and are not adjustable. On these models, as long as voltage is within a certain range, or less than 1.25 volts, TPS need not be serviced. On adjustable models, adjust TPS to specification and tighten retaining screws. See ON-VEHICLE ADJUSTMENTS article in this section.

OXYGEN (O2) SENSOR

O2 sensor is mounted in the exhaust pipe just below the exhaust manifold. It is equipped with a permanent pigtail which must be protected from damage when the sensor is removed.

1. Ensure sensor is free of contaminants, avoid using cleaning solvents of any type. Sensor may be difficult to remove when engine temperature is less than 120°F (48°C). Excessive removal force may damage threads in exhaust manifold or pipe.
2. Disconnect negative battery cable at battery. Disconnect electrical connector from oxygen sensor. Carefully remove oxygen sensor from exhaust pipe.

1. Whenever an oxygen sensor is removed, threads must be coated with anti-seize compound before it is reinstalled. New oxygen sensors will already have this compound applied to threads.
2. Install oxygen sensor in exhaust pipe and tighten sensor to 30 ft. lbs. (41 N.m). Reconnect electrical connector to oxygen sensor. Reconnect negative battery cable.

TURBOCHARGER ASSEMBLY

Note. Turbocharger is not serviceable and must be replaced as a unit.

Removal (2.0L VIN M)

1. Disconnect negative battery terminal. Raise vehicle. Drain cooling system. Remove lower fan retaining screw. Remove exhaust pipe. Remove rear A/C support bracket bolt. Loosen remaining bolts.
2. Remove oil drain tube at turbo. Lower vehicle. Remove coolant recovery pipe and move to one side. Remove induction tube, coolant fan, oxygen sensor, and oil feed pipe at union.
3. Remove air intake pipe and actuator vacuum hose. Remove exhaust manifold retaining nuts and lift out assembly. Remove turbocharger from exhaust manifold. Remove support bracket from turbine housing.

Removal (3.1L VIN V)

1. Disconnect negative battery terminal. Drain coolant from radiator. Remove intercooler-to-intake manifold duct. Remove air cleaner-to-turbocharger duct at turbo unit.
2. Remove air cleaner inlet duct assembly, air cleaner and intercooler duct at turbocharger. Remove turbocharger heat covers. Remove oxygen sensor.
3. Disconnect coolant return line and oil supply line at turbocharger. Disconnect vacuum lines at turbocharger compressor outlet and actuator assembly.
4. Remove wastegate actuator arm retaining clip and remove actuator arm from wastegate. Remove wastegate actuator from turbocharger. Remove cruise control servo and set aside.
5. Remove turbocharger downpipe, coolant hose and oil drain hose. Remove exhaust crossover from turbocharger. Remove turbocharger assembly.

Note. Each turbocharger has a unique sound or noise level when operating. If the sound cycles up and down, check for air restrictions in the intake tube and dirt build-up in the compressor housing/wheel. If a high pitched noise or whistle occurs, look for an inlet air or exhaust gas leak.

Inspection (All Models)

1. Check for loose duct connections from air cleaner to turbo assembly, cross-over duct to intake system. Check turbo wheels for impact damage from foreign objects and wheel contact against housing walls.
2. Check shaft for free rotation. Push inward on one of the shaft wheels while turning it by hand and feel for any rubbing or binding. Do the same on the other side. Wheels should turn freely without contacting hosing, backplate or shroud.
3. Check oil drain line for restriction. Any restriction can cause severe oil loss through the turbo seals. Check for traces of burned oil on turbine housing exterior. Check oil supply line for restrictions. Restricted oil flow will cause severe damage to turbocharger.

Installation (All Models)

Clean cylinder head and exhaust manifold mating surfaces prior to installing new gaskets. To install, reverse removal procedure. Tighten to specification; oil feed lines, coolant feed and return lines, oxygen sensor, air intake duct, and vacuum hose to actuator. See TORQUE SPECIFICATIONS at end of article.

Removal & Installation (2.0L VIN M & 3.1L VIN V)

1. Disconnect induction tube. On 3.1L (VIN V), drain cooling system. Remove coolant return line at turbocharger.
2. On all models, remove clip securing actuator rod to wastegate control arm. Remove vacuum hose. Remove actuator retaining screws and bolts. Remove actuator assembly.
3. To install, reverse removal procedure. Tighten retaining bolts to specification. See «TORQUE SPECIFICATIONS»(/buick/electra-park-avenue/1990-1990/remont/removal-installation/#engine-controls-removeinstalloverhaul__torque-specifications) table.

Scheme 14

1. Idle mixture screw plugs should be removed (if equipped) prior to disassembly of carburetor. Invert carburetor. Using hacksaw, saw 2 parallel cut areas in throttle body between locator points near idle mixture plug. (Scheme 14)
2. Distance between cut areas should be near size of punch to be used for plug removal. Cut downward to the plug. Cut area should not exceed more than 1/8" beyond locator points.
3. Place flat punch near end of cut areas. Holding punch at a 45 degree angle, drive punch inward toward throttle body to break casting away. Use a center punch to break plug and expose idle mixture screw. Repeat procedure for remaining plug.

DISASSEMBLY AIR HORN

1. Place carburetor in Holding Fixture (J-9789-118). Remove fuel filter, spring and fuel inlet nut. Remove Idle Load Compensator (ILC) assembly. Remove primary and secondary vacuum break assemblies and linkage (if equipped).
2. Air bleed valve cover must be removed. Seal bowl vents and air inlets with tape. Using a 7/64" drill bit, drill out head of air bleed valve cover retaining rivet.
3. Remove rivets and air bleed valve cover. Clean metal shavings from top of carburetor. Remove air bleed valve assembly. Remove "O" rings from air bleed valve.
4. Remove secondary metering rod holder retaining screw. Remove metering rod holder and metering rods. Remove choke lever retaining screw. Remove choke lever.
5. Pull upward on choke link. Hold intermediate choke lever outward while twisting choke link from lever. Remove pump link retainer at pump lever. Remove pump link from pump lever. DO NOT remove pump lever from air horn.
6. Remove air horn-to-float bowl retaining screws. Lift air horn straight up from main body. Invert air horn. Remove TPS plunger. NOTE: Use care not to damage mixture control solenoid connector, TPS adjustment lever and small tubes protruding from air horn. DO NOT attempt to remove small tubes.
7. Using small screwdriver, remove pump stem seal and TPS plunger seal retainer. Remove seals from air horn. Remove solenoid adjusting screw plug and adjusting screw (if equipped). (Scheme 16)

DISASSEMBLY FLOAT BOWL

1. Remove air horn-to-float bowl gasket. Remove mixture control solenoid plunger. Remove accelerator pump assembly. Remove spring and cup from accelerator pump.
2. Remove TPS and spring. Remove mixture control solenoid-to-air horn gasket. Remove solenoid connector retaining screws. Using Mixture Control Adjuster (J-28696-10 or BT-7928), remove solenoid mixture adjusting screw and rich limit stop.
3. Remove solenoid plunger. Remove primary metering rods and springs. Remove float bowl insert. Remove mixture control solenoid assembly. DO NOT remove plunger return spring or connector wires from solenoid.
4. Remove aneroid cavity insert. Remove solenoid return spring and adjusting screw spring. Remove float, needle and hinge pin.
5. Using Needle Seat Remover/Installer (J-22769), remove needle seat and gasket. Using Metering Jet Remover (J-28696-4 or BT-7928), remove primary jets. CAUTION: DO NOT remove secondary jets. Secondary jets are pressed into float bowl. If jets are damaged, float bowl must be replaced.
6. Remove discharge plug retainer, discharge ball and pump well baffle. Drill out choke cover retaining rivet heads. Remove choke cover retainers. Remove choke cover, thermostat assembly and gasket. Remove choke housing-to-float bowl retaining screw and washer.
7. Remove choke housing. Remove choke housing-to-float bowl seal. Remove secondary throttle lock-out lever. Remove intermediate choke lever. Invert float bowl. Remove intermediate choke shaft seal.
8. Remove internal choke thermostat lever retaining screw. Remove choke thermostat lever, intermediate choke shaft, lever and link assembly and fast idle cam. Separate fast idle cam from shaft. Remove intermediate choke shaft seal.

DISASSEMBLY THROTTLE BODY

1. Using Idle Mixture Socket (J-29030-B or BT-7610B), remove idle mixture screws and springs. Note and record number of turns required for idle mixture screw removal for reassembly reference.
2. Remove throttle body-to-float bowl retaining screws. Separate throttle body and gasket from float bowl.

CLEANING & INSPECTION

1. Clean parts thoroughly in carburetor cleaner. DO NOT soak solenoids, TPS, choke cover and thermostat assembly, plastic, or rubber parts in cleaner. After cleaning, rinse all metal parts with HOT water.
2. Blow dry with compressed air. Choke shaft must operate freely in air horn. Inspect idle mixture screws for grooves or nicks. Replace if damaged.
3. Inspect float for damage or fuel absorption. Inspect all solenoids for damaged wiring. Using ohmmeter, check mixture control solenoid resistance. Replace solenoid if resistance is not between 20-26 ohms.
4. Check mixture control solenoid for ground. Place one ohmmeter lead on solenoid case and remaining lead on one solenoid terminal. Resistance should be infinite. Replace solenoid if grounded.
5. Pump system operation should be checked. Install new pump cup and spring on pump plunger. Install pump discharge ball, plug and pump well baffle in float bowl. Fill float chamber and pump well with clean solvent.
6. Seal 2 pump discharge passages located on top of float bowl surface. Push pump assembly downward in well area. Pump should not reach bottom of travel area. Only movement should be compression of the duration spring.
7. Excessive pump travel indicates improper seating of pump cup, worn pump well or pump discharge plug is leaking. Repair defective components.
8. Refill float chamber and pump well with clean solvent. Slowly move pump downward in pump well until solvent appears at top of pump discharge passages. Remove pump assembly and note solvent level in passages.
9. Solvent level should not decrease. If level decreases, check for missing discharge ball, improper discharge ball seating or defective ball or seat. Repair as necessary.

REASSEMBLY FLOAT BOWL ASSEMBLY

1. Install new float bowl-to-throttle body gasket. Ensure all passages align. Install throttle body and retaining screw.
2. Install carburetor on holding fixture. Install idle mixture screws and springs. Adjust to location recorded during disassembly. Install intermediate choke shaft seal in choke housing with seal lips toward float bowl.
3. Install fast idle cam on intermediate choke shaft with stepped areas facing downward. Install cam and choke shaft in housing. Install choke thermostat lever on intermediate choke shaft. Install retaining screw.
4. Install choke shaft seal in float bowl with seal lips facing outward. Install choke housing seal in float bowl. Install secondary lock-out lever. Using Choke Lever Installer (J-23417), install intermediate choke lever in float bowl cavity.
5. Install choke housing assembly so intermediate choke shaft engages with intermediate choke lever. Ensure fast idle cam is located above vacuum break lever.
6. Install choke housing retaining screws. Check choke linkage for freedom of movement. Adjust choke coil lever adjustment. See «CHOKE COIL LEVER»(/buick/electra-park-avenue/1990-1990/remont/removal-installation/#engine-controls-removeinstalloverhaul__choke-coil-lever) under ADJUSTMENTS in this article.
7. Install pump well baffle with slot area toward bottom of float bowl. Install pump discharge ball and spring (if equipped). Install discharge ball plug. Install primary metering jets.
8. Using Needle Seat Installer (J-22769), install needle seat and gasket. Install float needle on float. Ensure float needle does not engage with slot area on float.
9. Install float hinge pin with open end facing pump well. Install float assembly. Adjust float level. See «FLOAT LEVEL»(/buick/electra-park-avenue/1990-1990/remont/removal-installation/#engine-controls-removeinstalloverhaul__float-level) under ADJUSTMENTS in this article.
10. Install mixture control solenoid return spring, adjusting screw spring and aneroid cavity insert (if equipped). Install mixture control solenoid with solenoid pin aligned with float bowl hole.
11. Install solenoid retaining screw and connector-to-air horn gasket. Adjust solenoid mixture screw. See «MIXTURE CONTROL SOLENOID MIXTURE SCREW»(/buick/electra-park-avenue/1990-1990/remont/removal-installation/#engine-controls-removeinstalloverhaul__mixture-control-solenoid-mixture-screw) under ADJUSTMENTS in this article.
12. Install float bowl insert, primary metering rods and springs. Install TPS adjusting spring and TPS. Push downward on connector to position below casting surface.
13. Install new cup and spring on accelerator pump. Install accelerator pump and spring. Install float bowl-to-air horn gasket. Install mixture control solenoid plunger.

REASSEMBLY AIR HORN

1. Using Mixture Control Adjuster (J-28696-10), install TPS adjusting screw. TPS final adjustment is made after carburetor installation. Install pump stem seal and TPS seal with seal lips facing outward.
2. Install seal retainers. Stake seal retainers in 3 places. Install TPS actuator plunger. Install mixture control solenoid stop screw and spring. Using Stop Screw Adjuster (J-28696-4), lightly seat stop screw then back out 1/4 turn.
3. Hold air horn gasket downward while installing air horn. Ensure accelerator pump aligns with hole of air horn. Using small screwdriver, hold TPS adjusting lever and plunger upward while installing air horn on float bowl.
4. Ensure air horn tubes align with float bowl and gasket. Install air horn screws. Tighten screws in proper sequence. (Scheme 15)
5. Install pump link in throttle lever and pump lever. Install pump link retainer. Install choke link in intermediate choke lever while holding fast idle cam upward.
6. Install choke lever on choke link. Engage choke lever with choke shaft. Install retaining screw. Install secondary metering rods and holder. Ends of metering rods must face each other. Install holder retaining screw.
7. Operate air valves to ensure freedom of movement. Coat new "O" rings for air bleed valve with ATF. Install "O" rings on air bleed valve with thick ring in upper groove and thin ring in lower groove.
8. Install air bleed valve. Adjust air bleed valve. Refer to «AIR BLEED VALVE»(/buick/electra-park-avenue/1990-1990/remont/removal-installation/#engine-controls-removeinstalloverhaul__air-bleed-valve) under ADJUSTMENTS in this article. Install and adjust vacuum break assemblies.
9. Install ILC. Install spring, fuel filter and fuel inlet nut. Tighten fuel inlet nut. Place fast idle cam on highest step.
10. Install choke cover, thermostat assembly and gasket in choke housing. Ensure coil tang engages with choke thermostat lever and cover notch aligns with housing projection. Install choke cover retainers and rivets. Perform necessary adjustments. See «ADJUSTMENTS»(/buick/electra-park-avenue/1990-1990/remont/removal-installation/#engine-controls-removeinstalloverhaul) in this article.
11. Install carburetor to intake manifold using new base gasket. Tighten bolts A-D in sequence to 12 ft. lbs. (16 N.m). (Scheme 15)

Scheme 15

Scheme 16

FLOAT LEVEL

1. Remove air horn, solenoid plunger, air horn gasket and metering rods. Remove plastic float bowl insert. If solenoid lean mixture screw requires removal, use Mixture Control Adjuster (J-28696 or BT-7928). Count and record number of turns required to lightly seat lean mixture screw prior to removal.
2. Install Bracket (J-34817-1 or BT-8227A-1) on float bowl. (Scheme 17) Install Float Positioner (J-34817-3 or BT-8227-A) on float bowl with pin contacting outer edge of float lever.
3. Using "T" Scale (J-9789-90 or BT-8037), measure distance from top of casting to top of float, approximately 3/16" from large end of float. Float level must be within 2/32" of float level specification. See «FLOAT LEVEL SPECIFICATIONS»(/buick/electra-park-avenue/1990-1990/remont/removal-installation/#engine-controls-removeinstalloverhaul) table.
4. If float level requires adjustment, use Float Adjuster (J-34817-15 or BT-8233) to bend float lever for correct setting. Recheck float level after each adjustment. Ensure float alignment is straight and does not contact float bowl.
5. Lightly seat lean mixture screw and readjust to original location (if removed). Reverse removal procedure for remaining components. Tighten air horn in correct sequence. (Scheme 15)

FLOAT LEVEL SPECIFICATIONS

Scheme 17

MIXTURE CONTROL SOLENOID MIXTURE SCREW

1. Install Mixture Control Solenoid Gauge (J-33815-1 or BT-8253-A) over throttle lever side metering jet guide. Temporarily install solenoid plunger.
2. Install lean mixture screw 6 threads. Install rich limit stop. Hold solenoid plunger downward against solenoid stop. Using Mixture Adjuster (J-28696-10 or BT-7928), slowly turn lean mixture screw in or out until solenoid plunger just contacts solenoid stop and mixture control solenoid gauge. (Scheme 18)
3. Adjustment is correct when solenoid plunger is contacting BOTH the solenoid stop and gauge. Remove solenoid plunger and gauge. Install plug at proper location. (Scheme 20)

Scheme 18

MIXTURE CONTROL SOLENOID STOP SCREW

1. With solenoid lean mixture screw properly adjusted and air horn installed, install Float Gauge (J-34935-1 or BT-8420-A) in air horn vent hole. Allow float gauge to contact mixture control solenoid plunger. (Scheme 19) Note line indicated with top of air horn casting.
2. Press downward on float gauge and note indicator mark. Release float gauge. This difference between the indicator lines is the solenoid plunger travel.
3. Using Stop Screw Adjuster (J-28696-10 or BT-7928), turn rich mixture stop screw until total solenoid travel equals 4/32" (3.17 mm).
4. After adjustment, install lean mixture screw plug and rich mixture stop screw plug. Plugs must be installed at specified location to seal settings and to prevent fuel vapor loss. (Scheme 20)

Scheme 19

Scheme 20

AIR BLEED VALVE

1. Install Air Bleed Valve Gauge (J-33815-2 or BT-8253-B) in throttle side of vent hole of air horn so gauge contacts solenoid plunger. (Scheme 21)
2. Position upper end of air bleed valve gauge over open cavity next to valve. Hold gauge downward so solenoid plunger is against solenoid stop and rotate gauge. Adjust air bleed valve so gauge pivots over and just contacts top of valve. (Scheme 21)

Scheme 21

AIR VALVE SPRING

1. Loosen shaft lock screw using Allen wrench. Rotate spring fulcrum pin counterclockwise until throttle valves open. (Scheme 22)
2. Rotate spring fulcrum pin clockwise until throttle valves close. Then rotate spring fulcrum pin proper amount of revolutions. See «E4MC CARBURETOR SPECIFICATIONS»(/buick/electra-park-avenue/1990-1990/remont/removal-installation/#engine-controls-removeinstalloverhaul) table.
3. Hold spring fulcrum pin and tighten lock screw. Apply a light coat of grease to spring contact area.

Scheme 22

CHOKE COIL LEVER

1. Remove choke cover retaining rivets. Remove choke cover and coil assembly from choke housing. (Scheme 23) Position fast idle cam on highest step of fast idle lever.
2. Push upward on choke coil lever to close choke valve. Install a.120" (3.04 mm) drill or pin gauge in choke housing hole. (Scheme 23) Lower edge of choke lever should just contact pin gauge. Bend choke rod to adjust.

Scheme 23

CHOKE ROD (FAST IDLE CAM)

1. Install rubber band to vacuum break lever of intermediate choke shaft. (Scheme 24) Open throttle, allowing choke valve to close. Install Angle Gauge (J-26701-A) on choke valve.
2. Adjust angle gauge to choke rod specification. Refer to the «E4MC CARBURETOR SPECIFICATIONS»(/buick/electra-park-avenue/1990-1990/remont/removal-installation/#engine-controls-removeinstalloverhaul) table. Place fast idle cam on second step of cam lever.
3. If cam lever does not contact cam, adjust fast idle screw. Bend tang on fast idle assembly until angle gauge bubble is centered. (Scheme 24)

Scheme 24

Note. Choke coil lever and choke rod (fast idle cam) adjustments must be correct before performing primary (front) vacuum break adjustment.

PRIMARY (FRONT) VACUUM BREAK

1. Install rubber band to vacuum break lever of intermediate choke shaft. Open throttle, allowing choke valve to close. Install Angle Gauge (J-26701-A) on choke valve. (Scheme 25)
2. Adjust angle gauge to specification. See «E4MC CARBURETOR SPECIFICATIONS»(/buick/electra-park-avenue/1990-1990/remont/removal-installation/#engine-controls-removeinstalloverhaul) table. Plug vacuum break bleed holes (if equipped).
3. Using vacuum pump, apply 15 in. Hg vacuum to vacuum break. Ensure bucking spring is seated. (Scheme 24) If air valve rod restricts vacuum break plunger from retracting, release vacuum and bend rod to allow full plunger travel.
4. Reapply vacuum and note bubble reading on angle gauge. Adjustment is correct when angle gauge bubble is centered. Adjust screw located on bucking screw to center bubble. (Scheme 24)

Scheme 25

Note. Choke coil lever and choke rod (fast idle cam) adjustments must be correct before performing secondary (rear) vacuum break adjustment.

SECONDARY (REAR) VACUUM BREAK

1. Install rubber band to vacuum break lever of intermediate choke shaft. Open throttle, allowing choke valve to close. Install Angle Gauge (J-26701-A) on choke valve. (Scheme 26)
2. Adjust angle gauge to specification. See «E4MC CARBURETOR SPECIFICATIONS»(/buick/electra-park-avenue/1990-1990/remont/removal-installation/#engine-controls-removeinstalloverhaul) table. Plug vacuum break bleed holes (if equipped).
3. Using vacuum pump, apply 15 in. Hg vacuum to vacuum break. Ensure bucking spring is compressed (if equipped). (Scheme 24) If air valve rod restricts vacuum break plunger from retracting, release vacuum and bend rod to allow full plunger travel.
4. Reapply vacuum and note bubble reading on angle gauge. Adjustment is correct when angle gauge bubble is centered. Rotate adjusting screw located on rear of vacuum break (if equipped). On models without adjusting screw, use Linkage Adjuster (J-9789-111) while supporting rod at "S" area and bend vacuum break rod. (Scheme 26)

Scheme 26

AIR VALVE ROD (FRONT)

1. Plug vacuum break bleed hole (if equipped). Using vacuum pump, apply 15 in. Hg vacuum to vacuum break. Ensure air valves are fully closed. (Scheme 27)
2. Measure clearance between rod and end of lever slot. Install a.015" (.38 mm) drill or pin gauge between rod and end of slot. (Scheme 29)
3. Bend rod at point shown to obtain a clearance of.015" (.38 mm) with vacuum applied. Reconnect vacuum hose to diaphragm.

Scheme 27

Note. Choke coil lever and choke rod (fast idle cam) adjustments must be correct before performing choke unloader adjustment.

CHOKE UNLOADER

1. Install rubber band to vacuum break lever of intermediate choke shaft. Open throttle, allowing choke valve to close. Install Angle Gauge (J-26701-A) on choke valve. (Scheme 28)
2. Adjust angle gauge to specification. See «E4MC CARBURETOR SPECIFICATIONS»(/buick/electra-park-avenue/1990-1990/remont/removal-installation/#engine-controls-removeinstalloverhaul) table. Hold secondary lock-out lever away from pin. (Scheme 28)
3. Hold throttle lever in wide open position. Note bubble on angle gauge. Adjustment is correct when angle gauge bubble is centered. Using Linkage Adjuster (J-9789-111), adjust fast idle lever to center bubble.

Scheme 28

SECONDARY THROTTLE VALVE LOCK-OUT LEVER (SIDE CLEARANCE)

1. Place fast idle cam on highest step of cam lever. Hold throttle lever closed. Measure secondary throttle valve lock-out side clearance between pin and lock-out lever. (Scheme 29)
2. Lock-out lever side clearance should be.010-.020" (.25-50 mm). Adjust clearance by bending pin.

SECONDARY THROTTLE VALVE LOCK-OUT LEVER (OPENING CLEARANCE)

1. Push down on tail of fast idle cam, allowing lock-out lever to move away from pin. Rotate throttle lever to position minimum clearance between lock-out lever and pin. (Scheme 29)
2. Measure specified opening clearance between end of pin and lock-out lever toe. (Scheme 29) Clearance should be.015" (.38 mm). Adjust clearance by filing end of pin.

Scheme 29

E4MC CARBURETOR SPECIFICATIONS

FUEL PRESSURE RELIEF

1. Fuel system is under pressure. Pressure must be relieved prior to servicing fuel system. Fuel pressure may be relieved by using one of 2 different methods.
2. One method is to disconnect fuel pump at rear body connector. Start engine and allow to run until it stops. Operate starter for 3 seconds to remove remaining fuel from fuel lines. Reconnect fuel pump once repair is completed.
3. The other method is to install Fuel Pressure Gauge (J-34730-1) on fuel pressure connection. Wrap shop towel around pressure connection when installing fuel pressure gauge to absorb fuel leakage.
4. Place gauge bleed hose in container. Open bleed valve to bleed fuel pressure.

Disconnect negative battery cable. Remove fuel filler cap. Since these TBI units contain an internal bleed-down feature, after a short time, system fuel pressure should dissipate.

Disassembly

Disassembly of throttle body unit for immersion in cleaning solvent requires removal of throttle body cover or fuel meter assembly, TPS and IAC assembly. Throttle valve screws are staked in position and should not be removed. Before working on throttle body assembly, it is essential that residual pressure be relieved before throttle body is removed. See FUEL PRESSURE RELIEF under FUEL SYSTEM (TBI) in this article.

THROTTLE BODY COVER (MODEL 220)

Place throttle body on Holding Fixture (J-9789-118 or BT 30-15) to prevent damage to throttle valve. Remove screws holding cover to throttle body, noting location of 2 short screws. Remove throttle body cover. (Scheme 31) Throttle body cover and pressure regulator are serviced as an assembly. DO NOT remove screws attaching pressure regulator to cover.

FUEL METER ASSEMBLY (MODEL 700)

Remove fuel meter-to-throttle body retaining screws. Remove fuel meter assembly. (Scheme 30) Discard gasket. If fuel pressure regulator cover is removed, regulator diaphragm must be replaced to prevent fuel leaks.

Scheme 30

Scheme 31

1. Clean all metal parts in a cold immersion-type cleaner such as Carbon X (X-55). Blow dry with compressed air.
2. DO NOT immerse TPS, IAC, throttle body cover, fuel meter assembly and pressure regulator assembly, fuel injector, fuel filter, rubber parts and diaphragms in cleaner solvent.
3. Inspect mating surfaces for damage that may prevent gasket sealing. Repair or replace components which may be cause of problems.

REASSEMBLY THROTTLE BODY COVER (MODEL 220)

1. Install new dust seal into recess of throttle body. Install fuel outlet passage gasket on cover. Install throttle body cover gasket on throttle body. Install cover, making sure that pressure regulator dust seal and cover gaskets are in place.
2. Apply thread locking compound to cover attaching screws. Install cover screws and lock washers. Tighten screws. Connect electrical lead to fuel injector and install air cleaner.

REASSEMBLY FUEL METER ASSEMBLY (MODEL 700)

1. Install new fuel meter-to-throttle body assembly gasket. Match cutout portions of gasket with openings in throttle body assembly.
2. Place fuel meter assembly on throttle body. Install fuel meter-to-throttle body retaining screws and washers (screws should be coated with locking compound). Tighten screws to specification. See «TORQUE SPECIFICATIONS»(/buick/electra-park-avenue/1990-1990/remont/removal-installation/#engine-controls-removeinstalloverhaul__torque-specifications) at end of article.
3. Install new "O" rings on fuel lines. Using a back-up wrench on fuel fittings, tighten fuel line nuts to 20 ft. lbs. (27 N.m). To complete reassembly, reverse disassembly procedure.

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

See also:
• TORQUE SPECIFICATIONS
• REMOVAL & INSTALLATION
• ON-VEHICLE ADJUSTMENTS
• FUEL SYSTEM (PFI)
• FUEL RAIL & INJECTORS
• FUEL PRESSURE RELIEF
• CHOKE COIL LEVER
• FLOAT LEVEL
• MIXTURE CONTROL SOLENOID MIXTURE SCREW
• AIR BLEED VALVE