Subaru Impreza 2003 Service Manual page 1008

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
FU(H4DOTC)-53, RELEASING OF FUEL PRES-
SURE, OPERATION, Fuel.>
4) Remove all the
IG(H4DOTC)-4, REMOVAL, Spark Plug.>
5) Fully open the throttle valve.
6) Check the starter motor for satisfactory perfor-
mance and operation.
7) Hold the compression gauge tight against spark
plug hole.
NOTE:
When using a screw-in type compression gauge,
the screw (put into cylinder head spark plug hole)
should be less than 18 mm (0.71 in) long.
8) Crank the engine by means of starter motor, and
then read the maximum value on the gauge when
the pointer is steady.
COMPRESSION
pressure. <Ref.
spark plugs. <Ref.
ME-00007
ME(H4DOTC)-34
9) Perform at least two measurements per cylinder,
and make sure that the values are correct.
Compression (350 rpm and fully open throttle):
Except for Australia model
Standard
981 — 1,177 kPa (10 — 12 kgf/cm
171 psi)
Limit
882 kPa (9.0 kgf/cm
Difference between cylinders
to
Less than 49 kPa (0.5 kgf/cm
Australia model (Except for STi model)
to
Standard
1.108 — 1,304 kPa (11 — 13 kgf/cm
189 psi)
Limit
951 kPa (10 kgf/cm
Difference between cylinders
Less than 49 kPa (0.5 kgf/cm
2
, 142 —
2
, 128 psi)
2
, 7 psi)
2
, 161 —
2
, 138 psi)
2
, 7 psi)