Subaru XT 1988 Service Manual page 143

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ON-CAR SERVICES
2-2
Engine Compression
MEASUREMENT
1) After warming up the engine, turn off the ignition switch.
2) Make sure that the battery is fully charged.
3) Remove all the spark plugs.
4) Disconnect the harness connectors for injectors.
5) Fully open the throttle valve.
6) Check the starter motor for satisfactory performance and
operation.
7) Crank the engine by means of the starter motor, and read
the maximum value on the gauge when the pointer is steady.
Hold the compression gauge tight against the spark plug hole.
8) Perform at least two measurements per cylinder, and
make sure that the values are correct.
Fig. 3
.~
c:
' " ' E
0
o
.~
__ II)
en ...
~
a.
- E
co
0
~
u
1,157 (11.8,168)
1,079 (11.0, 156)
.--------j
~dard
i
: I
I
I
~ Lirnit
961 (9.8,139)
I
I
I
I 883 (9.0, 128)
I
I
I
I I
(rpm)
200
Engine speed
350
L2-308
Difference between cylinders:
196 kPa (2.0 kg/cm
2
,
28 psi) or less
3
Intake Manifold Vacuum
MEASUREMENT
1) Warm up the engine.
2) Disconnect the vacuum hose and install the vacuum gauge
to the hose fitting on the manifold.
3) Keep the engine at the idle speed and read the vacuum
gauge indication.
By observing the gauge needle movement, the internal condi-
tion of the engine can be diagnosed as described in Table
below.