Lexus GS300/400 (2000 year). Service manual - part 129

EM0D0–01

A00982

CO/HC Meter

–

ENGINE MECHANICAL (2JZ–GE)

CO/HC

EM–1

1355

CO/HC

INSPECTION

HINT:
This check is used only to determine whether or not the idle
CO/HC complies with regulations.
1.

INITIAL CONDITIONS

(a)

Engine at normal operating temperature

(b)

Air cleaner installed

(c)

All pipes and hoses of air induction system connected

(d)

All accessories switched OFF

(e)

All vacuum lines properly connected

(f)

SFI system wiring connectors fully plugged

(g)

Ignition timing checked correctly

(h)

Transmission in neutral position

(i)

Tachometer and CO/HC meter calibrated by hand

2.

START ENGINE

3.

RACE ENGINE AT 2,500 RPM FOR APPROX. 180
SECONDS

4.

INSERT CO/HC METER TESTING PROBE AT LEAST
40 cm (1.3 ft) INTO TAILPIPE DURING IDLING

5.

IMMEDIATELY CHECK CO/HC CONCENTRATION AT
IDLE AND/OR 2,500 RPM

HINT:
When doing the 2 mode (2,500 rpm and idle) test, follow the
measurement order prescribed by the applicable local regula-
tions.

EM–2

–

ENGINE MECHANICAL (2JZ–GE)

CO/HC

1356

If the CO/HC concentration does not comply with regulations,
troubleshoot in the order given below.
(a)

Check heated oxygen sensors operation.
(See page 

DI–44

)

(b)

See the table below for possible causes, and then inspect
and correct the applicable causes if necessary.

HC

CO

Phenomenon

Causes

High

Normal

Rough idle

1. Faulty ignitions:

Incorrect timing

Fouled, shorted or improperly gapped plugs

Open or crossed high–tension cords

2. Incorrect valve clearance

3. Leaky intake and exhaust valves

4. Leaky cylinder

High

Low

Rough idle

(Fluctuating HC reading)

1. Vacuum leaks:

PCV hose

Intake manifold

Throttle body

Cylinder head gasket

2. Lean mixture causing misfire

High

High

Rough idle

(Black smoke from exhaust)

1. Restricted air filter

2. Plugged PCV valve

3. Faulty SFI systems:

Faulty pressure regulator

Faulty ECM

Faulty injector

Faulty throttle position sensor

Faulty mass air flow meter

B01982

LEXUS
Hand–Held
Tester

EM0D3–02

A02667

TC

E1

SST

DLC1

A02668

Igniter

White Lead Wire

A02637

EM–12

–

ENGINE MECHANICAL (2JZ–GE)

IGNITION TIMING

1366

IGNITION TIMING

INSPECTION

1.

WARM UP ENGINE

Allow the engine to warm up to normal operating temperature.

2.

CONNECT LEXUS HAND–HELD TESTER OR OBDII
SCAN TOOL

(a)

Connect the LEXUS hand–held tester or OBDII scan tool
to the DLC3.

(b)

Please refer to the LEXUS hand–held tester or OBDII
scan tool operator’s manual for further details.

3.

CONNECT TIMING LIGHT TO ENGINE

4.

CHECK IDLE SPEED (See page 

EM–13

)

5.

INSPECT IGNITION TIMING

(a)

Using SST, connect terminals TC and E1 of the DLC1.
SST

09843–18020

(b)

Connect the timing light clip to the white lead wire.

NOTICE:
Use a timing light that can detect the primary signal.

(c)

Using a timing light, check the ignition timing.
Ignition timing: 10 

± 2°

 BTDC @ idle

(Transmission in neutral position)

(d)

Remove the SST from the DLC1.

6.

FURTHER CHECK IGNITION TIMING
Ignition timing: 6 – 16

°

 BTDC @ idle

(Transmission in neutral position)

HINT:
The timing mark moves in a range between 6

°

 and 16

°

.

7.

DISCONNECT TIMING LIGHT FROM ENGINE

8.

DISCONNECT LEXUS HAND–HELD TESTER OR
OBDII SCAN TOOL

EM0D4–01

–

ENGINE MECHANICAL (2JZ–GE)

IDLE SPEED

EM–13

1367

IDLE SPEED

INSPECTION

1.

INITIAL CONDITIONS

(a)

Engine at normal operating temperature

(b)

Air cleaner installed

(c)

All pipes and hoses of air induction system connected

(d)

All accessories switched OFF

(e)

All vacuum lines properly connected

(f)

SFI system wiring connectors fully plugged

(g)

Ignition timing checked correctly

(h)

Transmission in neutral position

2.

CONNECT LEXUS HAND–HELD TESTER OR OBDII SCAN TOOL (See page 

EM–12

)

3.

INSPECT IDLE SPEED

(a)

Race the engine speed at 2,500 rpm for approx. 90 seconds.

(b)

Check the idle speed.
Idle speed: 700 

±

 50 rpm

If the idle speed is not as specified, check the throttle body.
4.

DISCONNECT LEXUS HAND–HELD TESTER OR OBDII SCAN TOOL