Compression Check - Toyota Celica Supra 1986 Service And Repair Manual

EM·8
ENGINE MEI;HANICAL - Compression Check
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COMPRESSION CHECK
NOTE : If there is lack of power, excessive oil consump·
tion or poor fuel m ileage, measure t he cylinder compres-
sion pressure.
1. WARM UP ENGINE
2 .
REMOVE SPARK PLUGS
3 .
DISCONNECT HIGH-TENSION CORD FROM DISTRIBUTOR
4 . MEASURE CYLINDER COMPRESSION PRESSURE
Ia) Insert a compression gauge into the spark plug hole.
lb) Fully open the throttle valve.
(c, W hi.., cranking the engine w ith the starter motor.
measure the compression pressure.
NOTE: Always use a f ully charged battery to obtain en-
gine revolution of more than 250 rpm.
ldl Repeat steps Ia) through (c) for each c ylinder.
Cornpression pressure:
11.5 kg/em' 1184 pol. 1,1 28 kPal
M inimum pressure:
9 .0
kg/em' 1 128 pel,
883
kPa)
Dlffarence
bet ween eech cylinder:
l eaa than 1.0 kgl cm' 114 pel, 98 kPa)
(e}
If C'l~'l inder
compression in one or more cylindeJs is lo w ,
pour a small amount of engine oil into t he cylinder
through the spar1< plug hole and repeat steps lal
through (c) for the cylinder w ith low compression.
• If adding o il llelps the compression. changes are
that the pist on rings and/or cylinder bore are worn
o r damaged.
• If
preswre
st ays low.
a
valve
may
be sticking or
seatied improperly, or there may be leak age pest
the gask et.