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Home/Chevrolet/Caprice Impala SS/Chevrolet Caprice Impala SS (1995-1996)/Repair manual/Removal & Installation/Engine Controls - Remove/install/overhaul
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Engine Controls - Remove/install/overhaul Chevrolet Caprice Impala SS

Removal & Installation 4 illustrations ~1747 words

INTRODUCTION

CAUTIONWhen battery is disconnected, vehicle computer and memory systems may lose memory data. Driveability problems may exist until computer systems have completed a relearn cycle. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION section before disconnecting battery.

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.

POWERTRAIN CONTROL MODULE (PCM)

CAUTIONElectronic components used in control systems are designed to carry very low voltages. As little as a 30-volt charge created by static electricity can cause a total or degrading failure in PCM or other electronic components containing integrated circuits. Before servicing PCM, ground yourself and ground work area to discharge stored electricity.
MovementRelative Humidity 10-20%Relative Humidity 65-90%
Handling Clear Plastic Bag20,0001200
Handling Vinyl Envelope7000600
Sliding On Velour Seat15,000400
Walking On Carpet35,0001500
Walking On Tile/Vinyl12,00050

STATIC CHARGE (VOLTS)

CAUTIONDO NOT remove part from packaging until ready to install. Ground any static-proof package before opening. DO NOT touch electrical terminals of components unless properly grounded. DO NOT lay electrical components on car seat, carpeting or dashboard. Use electrostatic protection mat and ground strap whenever possible. (Scheme 1)

Scheme 1

Scheme 1
Scheme 1

Note. Before replacing PCM, carefully inspect all wiring and control components. Failure to test for short circuits may result in repeated PCM failure due to grounds and Quad-Driver failure. To prevent internal damage to PCM, ensure ignition switch is in OFF position when disconnecting or reconnecting PCM connectors or 12-volt components.

Note. When replacing defective PCM, remove knock sensor module or PROM from defective PCM. New PCM does not come equipped with knock sensor module or PROM (if applicable). Install knock sensor module or PROM into new PCM.

Removal

Ensure ignition switch is in OFF position. Disconnect negative battery cable. Remove electrical connectors from PCM. Remove PCM from vehicle. Remove access cover and remove knock sensor module or PROM (if applicable) from PCM.

Installation

Install knock sensor module or PROM (if applicable) in new PCM. Install access cover. Install PCM into vehicle. Connect electrical connectors to PCM. Reconnect negative battery cable to battery.

Disconnect negative battery cable. Remove PCM from vehicle. See POWERTRAIN CONTROL MODULE (PCM) . Position PCM so access cover faces upward. Remove access cover from PCM. Using thumb and forefinger, squeeze both ends of PROM inward (outward on some models) and pull PROM up from access hole.

Note. Note reference notch locations in PROM and PCM for reassembly reference.

  1. Ensure new PROM has same service number as old one. Position PROM squarely over PCM PROM access hole. Press on outer edges of PROM until PROM is firmly seated in PCM. NOTE: Ensure reference notches in both PCM and PROM are properly aligned. If PROM is installed backward, PROM will be destroyed when ignition is turned on.
  2. Install PROM access cover on PCM. Install PCM in vehicle. See «POWERTRAIN CONTROL MODULE (PCM)»(/chevrolet/caprice-impala-ss/1995-1996/remont/removal-installation/#engine-controls-removeinstalloverhaul__powertrain-control-module-pcm) . Start engine and enter diagnostics. See appropriate TESTS W/CODES article in this section below. Check for diagnostic trouble codes. See appropriate TESTS W/CODES article in this section for code identification. «TESTS W/CODES - 4.3L»(/chevrolet/caprice-impala-ss/1995-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-43l) (for Caprice Only) «TESTS W/CODES - 5.7L»(/chevrolet/caprice-impala-ss/1995-1996/remont/testing-diagnostics/#engine-controls-tests-wcodes-57l) (for All Models)
  3. If code(s) sets, PROM is either not fully seated in PCM or installed backward, has bent pins or is defective. If bent pins crack when trying to straighten, replace PROM. If PROM is installed backward or is defective, replace PROM.

Removal & Installation

  1. Disconnect negative battery cable. Remove PCM from vehicle. See «POWERTRAIN CONTROL MODULE (PCM)»(/chevrolet/caprice-impala-ss/1995-1996/remont/removal-installation/#engine-controls-removeinstalloverhaul__powertrain-control-module-pcm) . Position PCM so access cover faces upward. Remove access cover from PCM.
  2. Using thumb and forefinger, squeeze both ends of knock sensor module inward and pull module up from access hole. To install, reverse removal procedure. Ensure module latches into holder in PCM.

Exploded View of Distributor. Scheme 2

Scheme 2: Exploded View of Distributor
Scheme 2: Exploded View of Distributor

Scheme 3

Scheme 3
Scheme 3
  1. Disconnect negative battery cable. Drain cooling system. Disconnect Intake Air Temperature (IAT) sensor harness connector. Remove knock sensor. Remove air intake duct. Remove serpentine belt. Remove coolant hoses to water pump assembly.
  2. Disconnect coolant temperature sensor harness connector. Remove water pump-to-engine block mounting bolts. Remove water pump assembly. Remove crankshaft harmonic balancer. Remove belt tensioner. Remove spark plug wires from distributor.
  3. Disconnect 4-terminal PCM connector from distributor. Remove 3 distributor mounting bolts. Pull distributor forward until distributor shaft disengages from engine. Mark top surface of distributor shaft for reassembly purposes.
  4. To install, ensure mark made on distributor shaft during removal is on top or facing up. To complete installation, reverse removal procedure. Refill coolant and check for leaks. Tighten distributor hold-down bolts to 106 INCH lbs. (12 N.m).

FUEL PRESSURE RELIEF

WARNINGAlways relieve fuel pressure before disconnecting any fuel injection-related component. DO NOT allow fuel to contact engine or electrical components.
  1. Fuel system is under pressure. Relieve pressure before servicing fuel system. Fuel pressure may be relieved using one of 2 different methods.
  2. One method is to disconnect fuel pump 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 complete.
  3. The other method is to install Fuel Pressure Gauge (J-34730-1) on fuel pressure test port. When installing fuel pressure gauge, wrap shop towel around pressure connection to absorb fuel leakage. Place gauge bleed hose in container. Open bleed valve to bleed fuel pressure.

THROTTLE BODY

Note. Ensure residual fuel pressure is relieved before working on throttle body.

  1. Relieve fuel pressure. See «FUEL PRESSURE RELIEF»(/chevrolet/caprice-impala-ss/1995-1996/remont/removal-installation/#engine-controls-removeinstalloverhaul__fuel-pressure-relief) . Disconnect negative battery cable. Remove air intake ducts. Disconnect and mark electrical connections and vacuum hoses from throttle body. Disconnect control cables from throttle body.
  2. Drain cooling system and remove coolant hoses to throttle body (if applicable). Remove throttle body retaining bolts. Remove throttle body and gasket.

Note. Identification number is stamped on throttle body. Use identification number to order replacement components.

  1. To install, reverse removal procedure using NEW gasket. Tighten retaining bolts to specification. See «TORQUE SPECIFICATIONS»(/chevrolet/caprice-impala-ss/1995-1996/remont/removal-installation/#engine-controls-removeinstalloverhaul) . Refill cooling system (if drained).
  2. If installing new Idle Air Control (IAC) valve, ensure IAC pintle length setting is adjusted before installation. See «IDLE AIR CONTROL (IAC) VALVE»(/chevrolet/caprice-impala-ss/1995-1996/remont/removal-installation/#engine-controls-removeinstalloverhaul__idle-air-control-iac-valve) . Adjust idle speed and TP sensor (if removed, and if adjustable). See «ADJUSTMENTS»(/chevrolet/caprice-impala-ss/1995-1996/remont/adjustments/#engine-controls-adjustments) article in this section.

FUEL PRESSURE REGULATOR

Note. On 3.4L (VIN S), 4.0L and 4.6L, fuel pressure regulator and fuel rail are serviced as an assembly only. DO NOT remove pressure regulator or pressure regulator cover from fuel rail.

  1. Relieve fuel pressure. See «FUEL PRESSURE RELIEF»(/chevrolet/caprice-impala-ss/1995-1996/remont/removal-installation/#engine-controls-removeinstalloverhaul__fuel-pressure-relief) . Disconnect negative battery cable. Remove resonator and resonator bracket. Disconnect pressure regulator vacuum hose. Remove fuel return line bracket and retainer clip. Remove fuel return line and "O" ring from pressure regulator. Remove fuel rail. See «FUEL RAIL & INJECTORS»(/chevrolet/caprice-impala-ss/1995-1996/remont/removal-installation/#engine-controls-removeinstalloverhaul) .
  2. Remove pressure regulator screws. Remove pressure regulator from fuel rail. Remove pressure regulator retainer and spacer assembly from fuel rail. Remove fuel inlet "O" ring from pressure regulator. Remove and discard filter screen if dirty.

To install, reverse removal procedure. DO NOT reuse "O" rings. Lubricate fuel inlet "O" ring with oil and install in regulator. Replace filter screen as necessary. Tighten screws to specification. See TORQUE SPECIFICATIONS .

  1. Relieve fuel pressure. See «FUEL PRESSURE RELIEF»(/chevrolet/caprice-impala-ss/1995-1996/remont/removal-installation/#engine-controls-removeinstalloverhaul__fuel-pressure-relief). Disconnect negative battery cable. Remove resonator and resonator bracket.
  2. Disconnect quick-connect fitting at fuel rail inlet and return lines. Disconnect vacuum hose at pressure regulator. Remove any vacuum lines as necessary to gain access to fuel rail and fuel lines. Remove electrical harness from routing clips on fuel rail.
  3. Remove fuel line retaining bolt. Disconnect electrical connectors from injectors. Remove fuel rail retaining bolts. Remove fuel rail from intake manifold using equal force on both sides of fuel rail. (Scheme 4) Remove injector-to-fuel rail retaining clip. Remove injector from fuel rail. Remove injector "O" rings and discard.

To install, reverse removal procedure. Lubricate NEW injector "O" rings with clean engine oil. Install injector-to-fuel rail retaining clip on right side of injector electrical connection. Position fuel rail on intake manifold. Push down on rail to seat injectors in manifold. Tighten fuel rail retaining bolts. See TORQUE SPECIFICATIONS . To complete installation, reverse removal procedure.

Locating Fuel Rail Assembly Components (4.3L & 5.7L). Scheme 4

Scheme 4: Locating Fuel Rail Assembly Components (4.3L & 5.7L)
Scheme 4: Locating Fuel Rail Assembly Components (4.3L & 5.7L)

IDLE AIR CONTROL (IAC) VALVE

CAUTIONFor calibration purposes, several different style IAC valves are used. Ensure replacement valve has the same part number as original valve.

Remove electrical connector from IAC valve. Remove IAC valve, gasket and "O" ring from throttle body assembly.

CAUTIONDO NOT extend or retract pintle if IAC valve has been in service, or damage to worm gear will result.
  1. Inspect gasket or "O" ring for damage. Replace as necessary. Check the extended distance of IAC pintle before installing. 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 pintle cone.
  2. To retract NEW IAC valve pintle, slowly exert finger pressure on valve. Install NEW "O" ring or gasket on valve. Coat "O" ring with clean engine oil. Install IAC valve. Tighten IAC valve to specification. See «TORQUE SPECIFICATIONS»(/chevrolet/caprice-impala-ss/1995-1996/remont/removal-installation/#engine-controls-removeinstalloverhaul) . Install electrical connector. To reset IAC valve, refer to «ADJUSTMENTS»(/chevrolet/caprice-impala-ss/1995-1996/remont/adjustments/#engine-controls-adjustments) article in this section.

IN-LINE FUEL FILTER

IMPORTANTThere is no service interval for fuel filter replacement. Only replace fuel filter if it is restricted. If it is restricted, the fuel tank should be inspected internally and cleaned if necessary.
  1. Remove negative battery cable.
  2. Relieve fuel system pressure. Refer to «FUEL PRESSURE RELIEF»(/chevrolet/caprice-impala-ss/1995-1996/remont/removal-installation/#engine-controls-removeinstalloverhaul__fuel-pressure-relief) .
  3. Raise vehicle.
  4. Remove fuel filter bracket attaching bolt.
  5. Remove quick-connect fittings.
  6. Remove fuel filter.
  1. Remove protective caps from new filter.
  2. Install new plastic connector retainers on filter inlet and outlet tubes. Install in same positions as on old filter noting direction of fuel flow arrow.
  3. Install quick-connect fittings.
  4. Trap in-line fuel filter over return pipe and install to frame with attaching bolt. Tighten In-line fuel filter attaching bolt: 89 lb. in. (10 N.m)
  5. Lower vehicle.
  6. Tighten fuel filler cap.
  7. Install negative battery cable.
  8. Turn ignition switch ON for 2 seconds. Turn to OFF for 10 seconds. Turn to ON and check for fuel leaks.
  1. Disconnect negative battery cable. Relieve fuel pressure. See «FUEL PRESSURE RELIEF»(/chevrolet/caprice-impala-ss/1995-1996/remont/removal-installation/#engine-controls-removeinstalloverhaul__fuel-pressure-relief) . Remove filler neck. Lower fuel tank. Disconnect fuel lines and electrical connection.
  2. Remove fuel level sending unit and fuel 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 away from bottom support. Use care not to damage rubber insulator and strainer. To install, reverse removal procedure using NEW "O" ring and gasket.

Turn ignition switch to OFF position. Disconnect electrical connector from TP sensor. Remove TP sensor retaining screws. Remove TP sensor from throttle body.

  1. With throttle valve in closed position, install TP sensor on throttle body. Ensure TP sensor lever engages with drive lever on throttle shaft. Install retaining screws and electrical connection.
  2. TP sensor is self-zeroing and is not adjustable. See «ADJUSTMENTS»(/chevrolet/caprice-impala-ss/1995-1996/remont/adjustments/#engine-controls-adjustments) article in this section.

OXYGEN SENSOR

Oxygen sensor is mounted in exhaust pipe, below exhaust manifold. It is equipped with a permanent pigtail which must remain intact when removing sensor.

  1. Ensure sensor is free of contaminants. DO NOT use 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. Disconnect electrical connector from oxygen sensor. Carefully remove oxygen sensor from exhaust pipe.
CAUTIONCorrect torque of oxygen sensor is critical to prevent crushing glass beads in graphite anti-seize compound. Crushing glass beads will cause sensor to seize in exhaust manifold. This may necessitate replacement of exhaust manifold at the next removal.
  1. Whenever an oxygen sensor is removed, coat threads with anti-seize compound before it is reinstalled. New oxygen sensors already have this compound applied to threads.
  2. Install oxygen sensor in exhaust pipe. Tighten sensor to 30 ft. lbs. (41 N.m). Reconnect electrical connector to oxygen sensor. Reconnect negative battery cable.

TORQUE SPECIFICATIONS

ApplicationFt. Lbs. (N.m)
Oxygen Sensor30 (41)
Throttle Body Bolts18 (24)
INCH Lbs. (N.m)
Crossover Tube Retainer Bolt44 (4.9)
Fuel Pressure Regulator Screws89 (10)
Fuel Rail Retaining Bolts89 (10)
Idle Air Control (IAC) Valve Housing28 (3.2)
Idle Air Control (IAC) Valve Screw26 (3.0)
Throttle Position Sensor Screw18 (2.0)

TORQUE SPECIFICATIONS

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