Compression, A: inspection, Me(h4dotc)-34 – Subaru Impreza 2004 User Manual
Page 35
ME(H4DOTC)-34
MECHANICAL
Compression
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.
SURE, OPERATION, Fuel.>
4) Remove all the spark plugs.
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.
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
2
, 142 —
171 psi)
Limit
882 kPa (9.0 kgf/cm
2
, 128 psi)
Difference between cylinders
Less than 49 kPa (0.5 kgf/cm
2
, 7 psi)
Australia model (Except for STi model)
Standard
1.108 — 1,304 kPa (11 — 13 kgf/cm
2
, 161 —
189 psi)
Limit
951 kPa (10 kgf/cm
2
, 138 psi)
Difference between cylinders
Less than 49 kPa (0.5 kgf/cm
2
, 7 psi)
ME-00007