Subaru Legacy (2005 year). Manual - part 270

ME(H4DOTC)-23

MECHANICAL

Idle Speed

3. Idle Speed

A: INSPECTION

1) Before checking the idle speed, check the fol-
lowing:

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

2) Idle the engine.
3) Stop the engine, and turn the ignition switch to
OFF.
4) Insert the cartridge to Subaru Select Monitor.
5) Connect the Subaru Select Monitor to data link
connector.
6) Turn the ignition switch to ON and the Subaru
Select Monitor power switch to ON.
7) Select {Each System Check} in Main Menu.
8) Select {Engine} in Selection Menu.
9) Select {Current Data Display & Save} in Engine
Control System Diagnosis.
10) Select {Data Display} in Data Display Menu.
11) Start the engine, and read the engine idle
speed.
12) Check the idle speed when no-loaded. (Head-
light, heater fan, rear defroster, radiator fan, A/C,
etc. are OFF.)

Idle speed [No load and gears in “N” or “P” 
range]:

650

±

50 rpm (AT model)

700

±

50 rpm (MT model)

13) Check the idle speed when loaded. (Turn the
air conditioning switch to “ON” and operate the
compressor for at least one minute before mea-
surement.)

Idle speed [A/C “ON”, and gears in  “N” or “P” 
range]:

825

±

50 rpm (AT model)

800

±

50 rpm (MT model)

NOTE:
Idle speed cannot be adjusted manually, because
idle speed is automatically adjusted. If the idle
speed is out of specification, refer to General Diag-
nostic Table under “Engine Control System”. <Ref.
to EN(H4DOTC)(diag)-2, Basic Diagnostic Proce-
dure.>

ME(H4DOTC)-24

MECHANICAL

Ignition Timing

4. Ignition Timing

A: INSPECTION

CAUTION:
After warming-up, engine becomes very hot.
Be careful not to burn yourself at measurement.
1) Before checking the ignition timing, check the
following:

(1) Ensure the air cleaner element is free from
clogging, spark plugs are in good condition, and
hoses are connected properly.
(2) Ensure the malfunction indicator light does
not illuminate.

2) Idle the engine.
3) Stop the engine, and turn the ignition switch to
OFF.
4) Insert the cartridge to Subaru Select Monitor.
5) Connect the Subaru Select Monitor to data link
connector.
6) Turn the ignition switch to ON and the Subaru
Select Monitor power switch to ON.
7) Select {Each System Check} in Main Menu.
8) Select {Engine} in Selection Menu.
9) Select {Current Data Display & Save} in Engine
Control System Diagnosis.
10) Select {Data Display} in Data Display Menu.
11) Start the engine and check the ignition timing at
idle speed.

Ignition timing [BTDC/rpm]:

14

°±

3

°

/650 (AT model)

14

°±

3

°

/700 (MT model)

If the timing is not correct, check the ignition control
system. Refer to “Engine Control System”. <Ref. to
EN(H4DOTC)(diag)-2, Basic Diagnostic Proce-
dure.>

ME(H4DOTC)-25

MECHANICAL

Intake Manifold Vacuum

5. Intake Manifold Vacuum

A: INSPECTION

1) Remove the collector cover.
2) Idle the engine.
3) Disconnect the brake vacuum hose from intake
manifold, and then install the vacuum gauge.
4) Keep the engine at idle speed and read the vac-
uum gauge indication.
By observing the gauge needle movement, internal
condition of the engine can be diagnosed with the
following procedures.

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

−

66.7 kPa (

−

500 mmHg, 

−

19.70 inHg) or less

ME-00801

Diagnosis of engine condition by measurement of intake 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 disconnected or 
damaged vacuum hose

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

Leakage around cylinder

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

Valve anchoring

4. 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 spring

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

Defective ignition system or throttle chamber idle adjustment

ME(H4DOTC)-26

MECHANICAL

Engine Oil Pressure

6. Engine Oil Pressure

A: INSPECTION

1) Remove the collector cover.
2) Remove the oil pressure switch from engine cyl-
inder block. <Ref. to LU(H4DOTC)-17, REMOVAL,
Oil Pressure Switch.>
3) Connect the oil pressure gauge hose to cylinder
block.
4) Connect the ground cable to battery.

5) Start the engine, and measure the oil pressure.

Oil pressure:

Standard (At 600 rpm)

98 kPa (1.0 kgf/cm

2

, 14 psi) or more

Standard (At 6,000 rpm)

588 kPa (6.0 kgf/cm

2

, 85 psi) or more

CAUTION:
• If the oil pressure is out of standard, check
the oil pump, oil filter and lubrication line. <Ref.
to LU(H4DOTC)-20, INSPECTION, Engine Lubri-
cation System Trouble in General.>
• If the oil pressure warning light comes ON
though the oil pressure is within standard, re-
place the oil pressure switch. <Ref. to
LU(H4DOTC)-20, INSPECTION, Engine Lubrica-
tion System Trouble in General.>

NOTE:
The standard is based on an engine oil tempera-
ture of 80

°C (176°F).

6) After measuring the oil pressure, install the oil
pressure switch. <Ref. to LU(H4DOTC)-17, IN-
STALLATION, Oil Pressure Switch.>

Tightening torque:

25 N

⋅

m (2.5 kgf-m, 18.4 ft-lb)

IN-00203

ME-00009