Compression Check - Toyota 3F-E Repair Manual Supplement

EM-16
ENGINE MECHANICAL —

COMPRESSION CHECK

HINT: If there is lack of power, excessive oil consump-
tion or poor fuel economy, measure the cylinder com-
pression pressure.
WARM UP AND STOP ENGINE
1.
DISCONNECT DISTRIBUTOR CONNECTOR
2.
DISCONNECT COLD START INJECTOR
3.
CONNECTOR
REMOVE SPARK PLUGS
4.
CHECK CYLINDER COMPRESSION PRESSURE
5.
Insert a compression gauge into the spark plug hole.
(a)
Fully open the throttle valve.
(b)
While cranking the engine with the starter, measure
(c)
the compression pressure.
HINT: Always use a fully charged battery to obtain en-
gine revolutions of more than 200 rpm.
NOTICE: This measurement must be done for as short
a time as possible.
Repeat steps (a) through (c) for each cylinder.
(d)
Compression pressure:
10.5 kg/cm' (149 psi, 1,030 kPa) or more
Minimum pressure:
8.0 kg/cm
Difference between each cylinder:
0.5 kg/cm
If compression of one or more cylinders is low, pour
(e)
a small amount of engine oil into that cylinder
through the spark plug hole and repeat steps (a)
through (c) for the cylinder with low compression.
• If adding oil helps the compression, probably the
• If pressure stays low, a valve may be sticking or
6. REINSTALL SPARK PLUGS
Torque: 180 kg-cm (13 ft-lb, 18 N•m)
7. RECONNECT COLD START INJECTOR
CONNECTOR
8. RECONNECT DISTRIBUTOR CONNECTOR
Compression Check
2
(114 psi, 785 kPa)
2
(7 psi, 49 kPa) or less
piston rings and / or cylinder bore are worn or
damaged.
seated improperly, or there may be leakage past
the gasket surface.