Tune-Up - v6 Buick Skylark VI

VEHICLE IDENTIFICATION & ENGINE NUMBER CODE

Engines may be identified by the 8th character of Vehicle Identification Number (VIN). The VIN is located on plate at the left front corner of instrument panel, and is visible through windshield.

VIN ENGINE & BODY CODES

MODEL & BODY IDENTIFICATION

MODEL & BODY IDENTIFICATION

TUNE-UP NOTES

Note. When performing tune-up procedures described in this article, the following notes and precautions must be followed

Always refer to Vehicle Emission Control Information Label in engine compartment before tune-up. If manual and label differ, always use label specifications.

With the exception of initial ignition timing, normal tune-up adjustments are not required. Perform adjustments only when indicated by the Computer Command Control (CCC) System Performance Check, CCC diagnostic charts and/or poor engine performance.

Do not allow or create a condition of engine misfire in more than one cylinder for an extended period of time. Damage to catalytic converter may occur due to loading converter with unburned air/fuel mixture.

Before making a compression test or cranking engine with a remote starting switch, disconnect ignition switch positive terminal lead at distributor or coils.

Do not add cleaning agents to fuel system as they can damage the catalytic converter.

Do not remove spark plug wires with engine running. Secondary ignition voltage may inflict harmful electrical shock.

Damage to electronic module and/or ignition coil(s) may result if tachometer terminal is grounded.

Note. On engines equipped with the C(3)I or Direct Ignition systems, a "Scan" tester, or equipment using special inductive adapters, must be used to obtain an RPM signal.

ENGINE COMPRESSION

Test compression pressure with engine at normal operating temperature. Remove all spark plugs. Set throttle valve wide open.

COMPRESSION SPECIFICATIONS

VALVE CLEARANCE

Note. The 2.8L (VIN S) is the only V6 with adjustable valves.

VALVE CLEARANCE ADJUSTMENT

2.8L & 3.1L

1. Left Bank - E-I-I-E-I-E (Front-to-rear).
2. Right Bank - E-I-E-I-I-E (Front-to-rear).

3.3L & 3.8L

1. Left Bank - E-I-E-I-I-E (Front-to-rear).
2. Right Bank - E-I-I-E-I-E (Front-to-rear).

IGNITION SYSTEM

The 2.8L (VIN S) engine is equipped with the High Energy Ignition (HEI) distributor system with Electronic Spark Timing (EST).

The 2.8L (VIN W) engine is equipped with the Direct Ignition System (DIS). The system uses a 3-coil module assembly with a crankshaft sensor in place of a distributor.

The 3.1L, 3.3L and 3.8L engines are equipped with C(3)I waste spark ignition system. The system uses a 3-coil module with crankshaft and camshaft sensors in place of a distributor.

IGNITION TIMING

Note. Some 2.8L (VIN S) engines are equipped with receptacle for magnetic timing probe timing meter, located 9.5 degrees ATDC. Do not use receptacle for timing with conventional light. Timing adjustment is not required on 2.8L (VIN W) with Direct Ignition System (DIS), or 3.1L, 3.3L and 3.8L engines with Computer Control Coil Ignition (C(3)I) ignition.

Engine must be at normal operating temperature. Disconnect EST timing connector. Place automatic transmission in Drive and turn off all accessories and A/C. The EST timing connector is taped to the engine harness at the rear of the engine. The wire is Tan/Blk single wire connector.

Note. Always refer to tune-up decal in engine compartment for timing procedures and specifications.

IGNITION TIMING SPECIFICATIONS

PICK-UP COIL TEST

Using an ohmmeter, check resistance across pick-up coil leads. Replace pick-up coil if resistance reading is not correct. See PICK-UP COIL RESISTANCE table.

PICK-UP COIL RESISTANCE

IGNITION COIL TEST

1. To check primary coil resistance, connect an ohmmeter between ignition coil primary terminal and coil frame. Reading should be infinite on high scale of meter. Disconnect ohmmeter from coil frame and connect it to the other coil primary terminal. Reading should be very low or zero, on low scale of meter. See IGNITION COIL RESISTANCE table.
2. To check secondary coil resistance, connect an ohmmeter between one coil primary terminal and coil secondary terminal. Reading should not be infinite on high scale of meter. See IGNITION COIL RESISTANCE table.

IGNITION COIL RESISTANCE

SPARK PLUG TYPE

SPARK PLUG TYPE

SPARK PLUG INSTALLATION

SPARK PLUG INSTALLATION

HIGH TENSION WIRE RESISTANCE TEST

Carefully remove ends of wire from spark plug and distributor or coils. Using an ohmmeter, check resistance while gently twisting wire. If resistance is not to specification or fluctuates, replace wire.

WIRE RESISTANCE

2.8L (VIN S) Firing Order. Scheme 6

2.8L (VIN W) & 3.1L Firing Order. Scheme 7

3.3L Firing Order. Scheme 8

3.8L Firing Order. Scheme 9

FUEL INJECTION

FUEL INJECTION

FUEL INJECTED

For fuel system pressure relief procedures, see appropriate article in FUEL SYSTEMS section. Also, see appropriate A-7 chart in COMPUTERIZED ENGINE CONTROLS section for fuel system diagnosis.

HOT (SLOW) IDLE RPM

Note. Engine idle speed is controlled by ECM and will vary. Small fluctuations are considered normal. If battery is disconnected, vehicle may have an unacceptable idle. Start and run engine for a minimum of 7 minutes to re-establish ECM control of idle.

IDLE AIR CONTROL VALVE

Note. Incorrect idle speeds are normally caused by dirty throttle plate or vacuum leaks. Ensure all vacuum components are functioning properly.

1. Install "Scan" tester to ALDL "test" terminal. Start and run engine until normal operating temperature is reached. Observe IAC counts. See MINIMUM IDLE SPEED chart.
2. If IAC counts are incorrect, use an awl to pierce minimum idle stop screw cover. Apply leverage to remove cover. Turn idle stop screw out until screw clears linkage. Turn screw in until screw touches linkage. Turn screw in an additional 1 1/2 turns.
3. Turn idle stop screw in to decrease IAC counts. Turn screw out to increase IAC counts. If minimum idle speed correction requires more than 1/2 turn of idle stop screw in or out, check for vacuum leaks or dirty throttle plate. Clear any trouble codes.

MINIMUM IDLE SPEED

MINIMUM IDLE SPEED

IDLE AIR CONTROL (IAC) VALVE RESET

If idle speed remains high and will not regulate down, reset IAC valve. To reset, run engine until normal operating temperature is reached. On 3.1L, reset is accomplished by placing transaxle in Drive for 2 minutes at idle.

On all other models, reset may be accomplished by grounding ALDL "test" terminal and operating engine at 2000 RPM, or by driving vehicle at a speed of 40 MPH for a few minutes to re-establish reference point between ECM and IAC valve. Ignition may have to be cycled on and off after above procedure to obtain proper idle.

THROTTLE POSITION SENSOR ADJUSTMENT

Throttle Position Sensor (TPS) can be adjusted with the use of "Scan" tester or by the following procedure

1. Install 3 jumper wires between TPS and harness connector.
2. Turn ignition on, engine off. Use digital voltmeter and connect to Dark Blue and Black wire terminals. With throttle at closed position, adjust TPS to obtain specified voltage.
3. Tighten screws and recheck readings. Turn ignition off. Remove jumper wires and reconnect harness connector to TPS.

TPS ADJUSTMENT VOLTAGE

ELECTRICAL SYSTEM

BATTERY SPECIFICATIONS

SERVICE INTERVAL MESSAGE RESET

To reset service interval message used on Pontiac 6000 STE with Drivers Information Center (DIC), proceed as follows. With service item displayed, press and hold down the reset button.

The distance between service intervals will decrease at a rate of 500 miles every 5 seconds. The reprogrammed distance to next service interval will be displayed when button is released. When the mileage interval reaches zero, the service item will light up. Repeat this operation to reset each service item (if required).

If the service interval light for each item is reset within 10 miles of coming on, the light will go out immediately. If the service interval light is left on longer than 10 miles, the display will remain on for 10 miles before going out.

REPLACEMENT INTERVALS

REPLACEMENT INTERVALS

BELT TENSION ADJUSTMENT

BELT TENSION ADJUSTMENT (1)

COOLING SYSTEM CAPACITIES

COOLING SYSTEM CAPACITIES

ENGINE OIL CAPACITIES

ENGINE OIL CAPACITIES

TRANSMISSION CAPACITIES

TRANSMISSION CAPACITIES