Compression - Subaru Legacy 2004 Service Manual

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2. Compression

A: INSPECTION

After warming-up, engine becomes very hot. Be

careful not to burn yourself during measure-

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 2.0)-38, RELEASING OF FUEL

PRESSURE, PROCEDURE, Fuel.>

4) Remove all the spark plugs. <Ref. to IG(H4SO

2.0)-5, 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 the

spark plug hole.

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 the starter motor,

and 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):

1,020 — 1,275 kPa (10.4 — 13.0 kgf/cm

148 — 185 psi)

Difference between cylinders:

49 kPa (0.5 kgf/cm

, 7 psi) or less

ME(H4SO 2.0)-22

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