Subaru Legacy IV (2008 year). Manual - part 56

ME(H4SO)-20

General Description

MECHANICAL

2. GENERAL TOOL

E: PROCEDURE

It is possible to conduct the following service procedures with engine on vehicle, however, the procedures
described in this section are based on the condition that the engine is removed from vehicle.
• V-belt
• Timing belt
• Valve rocker ASSY
• Camshaft
• Cylinder head

18354AA000

VALVE ROCKER 
HOLDER

Used for installing the valve rocker assembly 
(intake). (2-piece set)

18258AA000

SPRING 
INSTALLER

Used for installing the valve rocker assembly 
(intake).

TOOL NAME

REMARKS

Compression gauge

Used for measuring compression.

Vacuum gauge

Used for measuring intake manifold vacuum.

Oil pressure gauge

Used for measuring engine oil pressure.

Fuel pressure gauge

Used for measuring fuel pressure.

Timing light

Used for measuring ignition timing.

ILLUSTRATION

TOOL NUMBER

DESCRIPTION

REMARKS

ST18354AA000

ST18258AA000

ME(H4SO)-21

Compression

MECHANICAL

2. Compression

A: INSPECTION

CAUTION:
After warming-up, engine becomes very hot. Be
careful not to burn yourself during measure-
ment.
1) After warming-up the engine, turn the ignition
switch to OFF.
2) Make sure that the battery is fully charged.
3) Release the fuel pressure. <Ref. to FU(H4SO)-
43, RELEASING OF FUEL PRESSURE, PROCE-
DURE, Fuel.>
4) Remove all the spark plugs. <Ref. to IG(H4SO)-
4, REMOVAL, Spark Plug.>
5) Fully open the throttle valve.
6) Check the starter motor for satisfactory perfor-
mance and operation.
7) Secure the compression gauge tightly against
the spark plug hole.

NOTE:
When using a screw-in type compression gauge,
the screw should be less than 18 mm (0.71 in) long.
8) Crank the engine by the starter motor, and read
the maximum value on the gauge when the needle
of gauge is steady.

9) Perform at least two measurements per cylinder,
and check that the values are correct.

Compression (fully open throttle):

Standard

1,020 — 1,275 kPa 
(10.4 — 13.0 kgf/cm

2

, 148 — 185 psi)

Difference between cylinders

49 kPa (0.5 kgf/cm

2

, 7 psi) or less

10) After inspection, install the related parts in the
reverse order of removal.

ME-00192

ME(H4SO)-22

Idle Speed

MECHANICAL

3. Idle Speed

A: INSPECTION

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

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

2) Warm up the engine.
3) Read the engine idle speed using Subaru Select
Monitor. <Ref. to EN(H4SO)(diag)-34, READ CUR-
RENT DATA FOR ENGINE (NORMAL MODE),
OPERATION, Subaru Select Monitor.>
4) Check the idle speed when no-loaded. (Head-
light, heater fan, rear defroster, radiator fan, A/C
and etc. are OFF)

Idle speed [No load and gear in neutral, or “P”, 
“N” range]:

650

r

100 rpm (MT model)

700

r

100 rpm (AT model)

5) Check the idle speed when loaded. (Turn the A/C
switch to “ON” and operate the compressor for at
least one minute before measurement.)

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

850

r

100 rpm

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

ME(H4SO)-23

Ignition Timing

MECHANICAL

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 item:

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

2) Warm up the engine.
3) Stop the engine, and turn the ignition switch to
OFF.
4) Connect the timing light to #1 cylinder spark plug
cord, and then light the timing mark with the timing
light.
5) Start the engine and check the ignition timing at
idle speed as shown below.

Ignition timing [BTDC/rpm]:

10°

r

8°/650 (MT model)

15°

r

8°/700 (AT model)

If the timing is not correct, check the ignition control
system. <Ref. to EN(H4SO)(diag)-2, Basic Diag-
nostic Procedure.>

ME-02676

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