Subaru Legacy III (2000-2003 year). Manual - part 53

ME(H4SO)-24

MECHANICAL

IDLE SPEED

3. Idle Speed

A: INSPECTION

1) Before checking idle speed, check the following:

(1) Ensure the air cleaner element is free from
clogging, ignition timing is correct, spark plugs
are in good condition, and the hoses are con-
nected properly.
(2) Ensure that malfunction indicator light
(CHECK ENGINE light) does not illuminate.

2) Warm-up the engine.
3) Stop the engine, and then turn the igintion switch
to OFF.
4) When using the SUBARU SELECT MONITOR
<Ref. to ME(H4SO)-15, SPECIAL TOOLS, PREP-
ARATION TOOL, General Description.>

(1) Insert the cartridge to SUBARU SELECT
MONITOR.
(2) Connect the SUBARU SELECT MONITOR
to data link connector.

(3) Turn the ignition switch to ON, and SUBA-
RU SELECT MONITOR switch to ON.
(4) Select the {2. Each System Check} in Main
Menu.
(5) Select the {Engine Control System} in Se-
lection Menu.
(6) Select the {1. Current Data Display & Save}
in Engine Control System Diagnosis.
(7) Select the {1.12 Data Display} in Data Dis-
play Menu.
(8) Start the engine, and then read the engine
idle speed.

5) When using the tachometer (Secondary pick-up
type).

(1) Attach the pick-up clip to No. 1 cylinder
spark plug cord.
(2) Start the engine, and then read the engine
idle speed.

NOTE:
• When using the OBD-II general scan tool, care-
fully read its operation manual.
• This ignition system provides simultaneous igni-
tion for #1 and #2 plugs. It must be noted that some
tachometers may register twice that of actual en-
gine speed.
6) Check the idle speed when unloaded. (With
headlights, heater fan, rear defroster, radiator fan,
air conditioning, etc. OFF)

Idle speed [No load and gears in neutral (MT ve-
hicles), or N or P (AT vehicles) position]:

650

±±±±

100 rpm

7) Check the idle speed when loaded. (Turn the air
conditioning switch to “ON” and operate the com-
pressor for at least 1 minute before measurement.)

Idle speed [A/C “ON”, no load and gears in neu-
tral (MT vehicles) or N or P (AT vehicles) posi-
tion]:

850

±±±±

100 rpm

NOTE:
Idle speed cannot be adjusted manually, because
the idle speed is automatically adjusted.
If the specified idle speed cannot be maintained,
refer to General On-board Diagnosis Table under
“Engine Control System”. <Ref. to EN(H4SO)-2,
Basic Diagnostic Procedure.>

ME-00419

ME-00193

ME(H4SO)-25

MECHANICAL

IGNITION TIMING

4. Ignition Timing

A: INSPECTION

CAUTION:
After warming-up, engine becomes very hot. Be
careful not to burn yourself during measure-
ment.
1) Warm-up the engine.
2) To check the ignition timing, connect a timing
light to #1 cylinder spark plug cord, and illuminate
the timing mark with timing light.
3) Start the engine at idle speed and check the ig-
nition timing.

Ignition timing [BTDC/rpm]:

°±10°

/700 (MT vehicles)

°±

°°°°

/700 (2.5 L AT vehicles)

If the timing is not correct, check the ignition control
system.
Refer to Engine Control System. <Ref. to
EN(H4SO)-2, Basic Diagnostic Procedure.>

ME-00194

ME(H4SO)-26

MECHANICAL

INTAKE MANIFOLD VACUUM

5. Intake Manifold Vacuum

A: INSPECTION

1) Warm-up the engine.
2) Disconnect the brake vacuum hose, and then in-
stall the vacuum gauge to hose fitting on manifold.
3) Keep the engine at idle speed, and then read the
vacuum gauge indication.
By observing the gauge needle movement, the in-
ternal condition of engine can be diagnosed as de-
scribed below.

Vacuum pressure (at idling, A/C “OFF”):

Less than

−−−−

60.0 kPa (

−−−−

450 mmHg,

−−−−

17.72

inHg)

ME-00195

Diagnosis of engine condition by measurement of manifold vacuum

Vacuum gauge indication

Possible engine condition

1. Needle is steady but lower than normal position. This ten-
dency becomes more evident as engine temperature rises.

Leakage around intake manifold gasket or disconnection or
damaged vacuum hose

2. When engine speed is reduced slowly from higher speed,
needle stops temporarily when it is lowering or becomes steady
above normal position.

Back pressure too high, or exhaust system clogged

3. Needle intermittently drops to position lower than normal
position.

Leakage around cylinder

4. Needle drops suddenly and intermittently from normal posi-
tion.

Sticky valves

5. When engine speed is gradually increased, needle begins to
vibrate rapidly at certain speed, and then vibration increases as
engine speed increases.

Weak or broken valve springs

6. Needle vibrates above and below normal position in narrow
range.

Defective ignition system.

ME(H4SO)-27

MECHANICAL

ENGINE OIL PRESSURE

6. Engine Oil Pressure

A: INSPECTION

1) Disconnect the ground cable from battery.

2) Remove the generator from bracket. <Ref. to
SC(H4SO)-14, REMOVAL, Generator.>
3) Disconnect the connector from oil pressure
switch.
4) Remove the oil pressure switch from engine cyl-
inder block. <Ref. to LU(H4SO)-17, REMOVAL,
Oil Pressure Switch.>
5) Connect the oil pressure gauge hose to cylinder
block.
6) Connect the battery ground cable to battery.

7) Start the engine, and then measure the oil pres-
sure.

Oil pressure:

88 kPa (0.9 kg/cm

, 13 psi) or more at 800

rpm
294 kPa (3.0 kg/cm

, 43 psi) or more at

5,000 rpm

CAUTION:
• If the oil pressure is out of specification,
check the oil pump, oil filter and lubrication
line. <Ref. to LU(H4SO)-19, INSPECTION, En-
gine Lubrication System Trouble in General.>
• If the oil pressure warning light is turned ON
and oil pressure is in specification, replace the
oil pressure switch. <Ref. to LU(H4SO)-19, In-
spection, Engine Lubrication System Trouble
in General.>

NOTE:
The specified data is based on an engine oil tem-
perature of 80

C (176

F).

8) After measuring the oil pressure, install the oil
pressure switch. <Ref. to LU(H4SO)-17, Installa-
tion, Oil Pressure Switch.>

Tightening torque:

25 N·m (2.5 kgf-m, 18.1 ft-lb)

9) Install the generator and V-belt in the reverse or-
der of removal, and then adjust the V-belt deflec-
tion. <Ref. to ME(H4SO)-42, INSTALLATION, V-
belt.>

FU-00009

ME-00196

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