SECTION 6F3 - ENGINE TUNE – GEN III V8 ENGINE

CAUTION:

This vehicle will be equipped with a Supplemental Restraint System (SRS). A SRS will consist of either

seat belt pre-tensioners and a driver's air bag, seat belt pre-tensioners and a driver's and front

passenger's air bag s or seat belt pre-tensio ners, driver’s an d f ront passenger’s air b ag an d lef t an d rig ht

hand side air bags. Refer to SAFETY PRECAUTIONS, Section 12M , Supplemental Restraint System of the

VT Series I Service Information before performing any service operation on, or around any SRS

components, the steering mechanism or wiring. Failure to follow the SAFETY PRECAUTIONS could

result in SRS deployment, resulting in possible personal injury or unnecessary SRS system repairs.

CAUTION:

Whenever any component that forms part of the ABS or ABS/ETC (if fitted), is disturbed during Service

Operations, it is vital that the complete ABS or ABS/ETC system is checked, using the procedure as

detailed in 4. DIAGNOSIS, ABS or ABS/ETC FUNCT ION CHECK, in Section 12L ABS & ABS/ETC, in either

the VT Series I Service Inforamation (V6) or in the VT Series II Service Information (GEN III V8) of this

Service Information CD.

1. GENERAL INFORMATION

Engine tuning, is sim plified by electronic control of both the air/fuel m ixture and the ignition timing. The ratio of the

air/fuel mixture is controlled to near optimum condition by the Powertrain Control Module (PCM) refer to Section

6C3 POWERTRAIN MANAGEMENT – GEN III V8 ENGINE in the VT Series II Service Information.

Should the air/fuel mixture operate outside specified limits, the PCM will set a Diagnostic Trouble Code and the

Check Engine Light will be illuminated.

Engine tune specif ications nec essar y to achieve the

correct emission levels are located on the Vehicle

Emission Control Information Label, located in the

engine compartment (1). The label should be

referred to before making any adjustments.

To maintain the performance and emission control

levels specified for the vehicle, it is necessary for

regular m aintenanc e to be per f ormed in ac c ordanc e

with the schedule set out in the VT Series Owner's

Handbook.

Figure 6F3-1

Figure 6F3-2

The chart set out in 2. ENGINE TUNE RECOMMENDATIONS details the recommended items requiring attention

during an engine tune and cross reference is provided to the appropriate source of information in the Service

Manual.

There is no pr ovis ion f or ignition timing, idle s peed and idle mixtur e adj ustments on VT Ser ies Models fitted with the

GEN III V8 engine, (refer to Section 6C3 POW ERTRAIN MANAGEM ENT – G EN III V8 ENGINE of the VT Series II

Service Information).

2. ENGINE TUNE RECOMMENDATIONS

ENGINE TUNE RECOMMENDATIONS VT SERVICE MANUAL

REFERENCE SECTION

ENGINE COMPRESSION TEST SECTION 6A3, ENGINE MECHANICAL – GEN

III V8 ENGINE. ALSO REFER TO 3.1 TUNING

SERVICE NOTES IN THIS SECTION.

ENGINE DRI VE BE LT CHECK SECTI ON 6A 3, ENGINE MECHANICAL – GEN

III V8 ENGINE.

COOLING SYSTEM CHECK FOR LEA K S SECTION 6B3, ENGINE COOLI NG – GE N III

V8 ENGINE.

VALVE LASH ADJUSTMENT NON-ADJUSTABLE HYDRAULIC LIFTERS

IDLE SPEED NON-ADJUSTABLE

IDLE MIXTURE NON-ADJUST ABLE

AIR CLEANER CHECK OR REPLACE, TEST FOR LEAKS SECTION 6C3, POWERTRAIN

MANAGEMENT – GEN III V8 ENGINE.

FUEL FILTER CHECK AND REPLACE SECTION 6C3, POWERTRAIN

MANAGEMENT – GEN III V8 ENGINE.

SPARK PLUGS CLEAN, ADJUST OR REPLACE SECTION 6D3-3, IGNITION SYSTEM – GEN

III V8 ENGINE.

SPARK PLUG LEADS TEST FOR CONTINUITY SECTION 6D3-3, IGNITION SYSTEM – GEN

III V8 ENGINE.

IGNITION TIMING NON-ADJUST ABLE

EXHAUST SYSTEM CHECK FOR EXCESSIVE BACK PRESSURE

AND GENERA L CONDITION SECTION 8B, EXHAUST SYSTEM AND

SECTION 6C3, P OWERTRAIN

MANAGEMENT – GEN III V8 ENGINE.

ENGINE VENTILATION CHECK SECTION 6E3, EMISSION CONTROL – GEN

III V8 ENGINE.

EVAPORATIVE EMISSION

CONTROL CHECK LINES, HOSES AND CANISTER SECTION 6E3, EMISSION CONTROL.

BATTERY AND CABLES CHECK SECTION 12A, BATTERY AND CABLES.

3. ENGINE TUNI NG DATA

ENGINE TYPE TRANSMISSION IDLE SPEED

ENGINE WARM

(rpm)

IGNITION TIMING SPARK PLUGS

5.7 LITRE P . F. I. –

GEN III V8 MANUAL

AUTOMATIC

TRANSMISSION

800 ± 50

650 ± 50

(IN NEUTRAL)

550 ± 50

(IN DRIV E)

NON-ADJUSTABLE

(PCM

CONTROLLED)

TYPE

AC 41-952

GAP (mm)

1.52 ± 0.05 mm

NOTE: Idle speed is non-adj ustable (PCM c ontrolled) and varies with: - Battery vol tage

- Engine temperature

- Air condi t i oni ng request

- Park/Neutral Switch Signal (Aut omati c Transmiss i on onl y)

3.1 TUNING SERVICE NOTE S

CAUTION: TO PREVENT BOTH FUEL BEING

INJECTED INTO THE CYLINDERS AND

IGNITION DURING CRANKING, REMOVE THE

EFI RELAY (1) WHEN PERFORMING A

COMPRESSION TEST.

For compression testing procedure and

specifications, refer to Section 6A3 ENGINE

MECHANICAL – GEN III V8 ENGINE, in this

Service Information CD.

1. DO NOT operate the engine with any spark

plugs or spark plug leads disconnected as

damage to the Ignition System or PCM may

result.

2. Make all engine checks with engine coolant

and oil at normal operating temperatures,

preferably achieved by driving.

3. Ensure that the air conditioner (where fitted) is

switched OFF.

4. Verify that check powertrain light is OFF with

the engine running.

Figure 6F3-3

3.2 CYLINDE R BALANCE CHECK

1. Connect TECH 2 to the Data Link Connector

(refer to Section 0C T ECH 2 of the VT Series II

Service Information).

2. Select VT Commodore \ Engine \ Functional

Tests, Power Balance.

3. Perform Power Balance as directed by TECH 2.

NOTE 1: Engine rpm readings displayed on TECH

2 should be within 50 rpm for all cylinders.

NOTE 2: Any cylinder that does not cause a drop in

engine idle speed is misfiring.

Once the suspect cylinder has been isolated, the

cause of the problem will still need to be

determined. Reasons include fuel, spark or engine

mechanical problems.

The f ollowing are a few quick check s to help isolate

the cause of the engine misfire. For additional

diagnostic information refer to Section 6C3

POWERTRAIN MANAGEMENT – GEN III V8

ENGINE of the VT Series II Service Information. Figure 6F3-1

IGNITION

1. Remove spark plug lead (1) from plug and

engine harness connector from injector of

misfiring cylinder.

2. Install Test Plug, Tool No. 7230 and connect

to a good engine earth point (2).

Failure to properly earth the Test Plug 7230

can result in damage to ignition system

components due to excessive secondary

voltages required to fire the 7230.

NOTE: Avoid placing the Test Plug 7230 near

sensors, modules or other electronic equipment

that may be affected by electromagnetic

interference.

3. Start and run engine. If tester shows good

spark, check for faulty spark plug.

If weak or no spark, check lead for short to

earth, open or very high resistance in spark

plug lead.

NOTE: If any lead is open circuited, recheck coil

secondary resistance, as it may have been

damaged by high voltage produced by open circuit.

Figure 6F3-5

FUEL

1. Disconnect engine wiring harness connector

(1) from injector of cylinder that is misfiring.

Install injector node light tester, Tool No.

BT-8329 into connector (1) and start engine.

2. Check tester for light flashing.

a. If the light either does not flash or is

erratic, check engine harness between

connector and PCM for continuity.

b. If flashes are regular, check for blocked or

faulty injector (refer to Section 6C3

POWERTRAIN MANAGEMENT – GEN III

V8 ENGINE of the VT Series II Service

Information).

Figure 6F3-6

MECHANICAL

Perform compression test as outlined in

Section 6A3 ENGINE MECHANICAL - GEN

III V8 ENGINE in this Service Inforatmation

CD.

4. SPECIAL TOOLS

TOOL NO. REF IN TEXT TOOL DESCRIPTION COMMENTS

TECH 2 TECH 2 DIAGNOSTIC TOOL Previously released.

7230 TEST PLUG Previously released.

BT-8329 INJECTOR NODE LIGHT TESTER Previously released.