Tune-Up - 4-cyl Chevrolet Corsica I

VEHICLE IDENTIFICATION NUMBER CODE

Engine can be identified by the 8th character of Vehicle Identification Number (VIN). The VIN is located on a plate, attached to top left corner of instrument panel and visible through windshield.

VIN ENGINE & BODY CODES

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 performing tune-up. If manual and label differ, use label specifications.

With the exception of initial ignition timing, normal tune-up procedures are not required. Adjust fuel system only when indicated by the Computer Command Control (CCC) System Performance Check, or by poor engine performance.

Do not remove spark plug wires with engine running. High Energy Ignition (HEI) secondary voltage may inflict harmful electrical shock.

Damage to the electronic control module and/or coil may result if the tachometer terminal is grounded. Before making compression test or cranking engine with a remote starter switch, disconnect the battery terminal connector from distributor.

Do not allow or create engine misfire in more than one cylinder for an extended period of time. Damage to catalytic converter will occur.

Use only fuel system cleaning agents recommended by the manufacturer.

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

On models equipped with Direct Ignition Systems (DIS), disconnect battery terminal connector from coil. On 2.3L models, Integrated Direct Ignition (IDI) cover and 11-pin IDI harness connector should be removed. On other models, disconnect battery terminal connector from distributor.

Check compression pressure with engine warm, all spark plugs removed and throttle valve wide open. Crank engine through 6 compression strokes before reading compression gauge.

COMPRESSION SPECIFICATIONS

VALVE CLEARANCE

VALVE CLEARANCE ADJUSTMENT

2.0L (VIN K & M)

E-I-E-I-E-I-E-I (Front-to-rear).

2.0L (VIN 1)

E-I-I-E-E-I-I-E (Front-to-rear).

2.3L (VIN A & D)

1. Right side - Intake
2. Left Side - Exhaust

2.5L (VIN R & U)

I-E-I-E-E-I-E-I (Front-to-rear).

DISTRIBUTOR

The 2.0L (VIN 1) and 2.5L (VIN R and U) engines use a Direct Ignition System (DIS). Ignition timing information is taken from a crankshaft mounted timing disc by a magnetic sensor.

The 2.3L (VIN A and D) engines use the Integrated Direct Ignition (IDI) system and does not use the conventional distributor and coil. The system consists of 2 separate ignition coils, an ignition module and a secondary conductor housing mounted to the aluminum cover plate. This system utilizes the EST (Electronic Spark Timing) signal from the ECM to control spark timing.

The 2.0L (VIN K and M) engines are equipped with the Delco-Remy High Energy Ignition system with Electronic Spark Timing HEI-EST). The HEI-EST distributor is not equipped with centrifugal or vacuum advance mechanisms since all advance is controlled by the Electronic Control Module (ECM). (Scheme 1)- (Scheme 5).

PICK-UP COIL RESISTANCE (OHMS)

2.3L

Remove aluminum engine cover. Suspend the ignition cover from hood leaving the primary harness connected. Primary coil resistance should read 0.5 ohm.

2.0L & 2.5L

1. Connect ohmmeter between ignition coil primary 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.
2. Disconnect ohmmeter lead from one of coil primary terminals and connect it to coil secondary terminal. Reading should not be infinite on high scale of meter.

IGNITION TIMING

Note. Some engines are equipped with a receptacle for a magnetic probe timing light, located 9.5 degrees ATDC. Do not use this receptacle with a normal timing light.

1. Set parking brake and block drive wheels. Warm engine to normal operating temperature with air cleaner installed. Turn electric cooling fan and A/C off. Place transmission in neutral or park.
2. Verify that "SERVICE ENGINE SOON" (SES) light is not on. Ground diagnostic connector under dash by installing jumper wire between "A" and "B" terminals. "SES" light should begin to flash. Connect timing light to No. 1 spark plug lead and record position of timing mark.
3. Disconnect timing light from No. 1 cylinder and connect to No. 4 cylinder. Check timing and record position of timing mark.
4. To obtain average timing, add both timing figures together and divide by 2. If timing is incorrect, adjust average timing by turning distributor.
5. Remove ground from diagnostic connector. If "SES" light remains on, remove ECM fuse from fuse block (or disconnect ECM pigtail at battery) for 10 seconds.

IGNITION TIMING SPECIFICATIONS

SPARK PLUGS

SPARK PLUG TYPE

SPARK PLUG INSTALLATION

HIGH TENSION WIRE RESISTANCE

Carefully remove high tension wire from spark plug and distributor. Using an ohmmeter, check resistance while gently twisting wire. If resistance is too high, replace wire. High tension wires are not used on 2.3L models.

HIGH TENSION WIRE RESISTANCE

2.0L (VIN K & M) Firing Order & Timing Marks. Scheme 1

2.0L (VIN 1) Firing Order & Timing Marks. Scheme 2

2.3L (VIN A & D) Firing Order & Timing Marks. Scheme 3

2.5L (VIN R) Firing Order & Timing Marks. Scheme 4

2.5L (VIN U) Firing Order & Timing Marks. Scheme 5

FUEL SYSTEM

GASOLINE 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 (IAC) VALVE

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

1. Ensure engine is at normal operating temperature. Ground ALDL diagnostic "test" terminal. With ignition on and engine off, wait 30 seconds for IAC valve to seat in throttle body.
2. Disconnect IAC valve electrical connector. Connect tachometer or "Scan" tester to monitor engine RPM. Disconnect ground from ALDL "test" terminal.
3. With transaxle in park or neutral, start engine and allow engine RPM to stabilize. Ensure all accessories are turned off. Observe idle speed. See MINIMUM IDLE SPEED SPECIFICATIONS chart.
4. If idle speed is incorrect, remove air cleaner to gain access to throttle body (if necessary). Plug any hoses disconnected. Disconnect throttle cable and TV cable (on automatic transaxle models). Use an awl to pierce minimum idle stop screw cover. Apply leverage to remove cover.
5. Using minimum idle stop screw, adjust engine idle speed to specification. 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.

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 SPECIFICATIONS chart.
2. If idle speed is 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 SPECIFICATIONS

Idle Air Control Valve (IACV) Reset

If the idle speed remains abnormally high and will not regulate down, reset the IACV. To reset, run engine until it reaches normal operating temperature. Reset may be accomplished by grounding ALDL "test" terminal and operate engine at 2000 RPM for a few seconds, or by driving vehicle at a speed of 40 MPH for a few moments to re-establish reference point between ECM and IACV. Ignition may have to be cycled on and off after above procedure to obtain proper idle.

Throttle Position Sensor (TPS)

1. Throttle position sensors are not adjustable. Check should be performed only when throttle body or TPS has been replaced, or after minimum idle speed has been adjusted.
2. Connect a digital voltmeter from TPS connector center terminal "B" to outside terminal "A". With ignition on and engine off, the TPS voltage should be less than 1.25 volts at closed throttle. As throttle valve is opened, output increases to about 5.0 volts at wide-open throttle.

IDLE MIXTURE ADJUSTMENT

Note. Idle mixture is controlled by the Electronic Control Module (ECM). No adjustment is required or possible.

BATTERY

BATTERY SPECIFICATIONS

SERVICE INTERVALS

REPLACEMENT INTERVALS

ADJUSTMENTS

BELT TENSION ADJUSTMENT (1)

CAPACITIES

COOLING SYSTEM CAPACITIES

ENGINE OIL CAPACITY

TRANSMISSION CAPACITIES