EM-26 ENGINE MECHANICAL - Compression Check
d
COMPRESSION CHECK
NOTE: If there is lack of power, excessive oil consump-
tion or poor fuel mileage, measure the cylinder compres-
sion pressure.
(7M-GE)
1.
2.
3.
4.
5.
6. REMOVE SPARK PLUGS (See page IO-71
7.
EM3003
WARM UP ENGINE
DISCONNECT COLD START INJECTOR CONNECTOR
DISCONNECT SOLEtiOlD RESISTOR CONNECTOR
DISCONNECT DISTRIBUTOR CONNECTOR
REMOVE THROTTLE BODY
(a) Remove the PCV hose.
(b) Disconnect the water by-pass hoses and plug the
hose end.
(c) Disconnect following hoses:
. fwl EGR)
VSV hoses
. (wl TWC)
BVSV hoses
. (w/ EGR)
EGR vacuum modulator hoses
l No.7 air hose
id) Disconnect the throttle position sensor connector.
(e) Remove the throttle body bracket(s).
(f) Remove the four bolts, throttle body and gasket.
CHECK CYLINDER COMPRESSION PRESSURE
(a) Insert a compression gauge into the spark plug hole.
(b) While cranking the engine with the starter motor,
measure the compression pressure.
NOTE: Always use a
fully charged battery to obtain an
engine revolution of more than 250 rpm.
(c) Repeat steps Ia) through Ib) for each cylinder.
Compression pressure:
11.0 kg/cm2 (156 psi, 1,079 kPa) or more
Minimum pressure:
9.0 kg/cm2 (128 psi, 883 kPa)
Difference between each cylinder:
1 .O kg/cm2 (14 psi, 98 kPa) or less
(d) If cylinder compression in one or more cylinders is
low, pour a smali amount of engine oil into the
cylinder through the spark plug hole and repeat steps
(a) through (b) for the cylinder with low compression.
0 If adding oil helps the compression, chances are
that the piston rings and/or cylinder bore are worn
or damaged.
0 If pressure stays low, a valve may be sticking or
seating improperly, or there may be leakage past
the gasket.
