Compression - Mazda 121 Workshop Manual

COMPRESSION
COMPRESSION
ll rhe enoine exnibits low power. poor luel economy or poor ldle check the lollowing:
1. lgnrtro; system (Beler to Sectron G.)
2. Compressron
3. Fuel svstem (Fefer to Section F.)
INSPECTION
1 . Verifv that the battery is tully charged Recharge it if neces-
sarv. (Refer to Section G.)
2. Warm up the engine to normal operating lemperature'
3. Turn the engine OFF.
4. Bemove all spark plugs.
5. Disconnect the ignition coil connector'
6. Connect acompression gaugetothe No l spark plug hole
7. Fr.rlly depress lhe acceleiator pedal and crank the engine'
8. Record the maxrmum gauge reaolng
9. Check each cylinder.
Compression
kPa (kg/cm', psilrpm
B3
Siandard
1412 1t4.4, 2O4!3OO
1030 00.5, 149)-300
't96 (2.O, 26)
10. lf the compression in one or more cyllnders s rcw' pour a
small amount of engine oil into the cylinder and recheck
the compressrcn.
(1) lt the compression increases, the piston, piston rings'
or cvlinder wall mav be worn
(2) lf the compression stays low, the valve may be stuck
or seating imProperly.
{3) lt the comoression in adjacent cylinders stays low, the
' '
cvlinder head gaskel may be delective or the cylinder
head distorted.
11 . Connect the ignition coil connector.
12. Apply antiseize compound or molybdenum-based
lubricant
to the spark Plug threads.
13. Insiallthe spark Plugs.
Tidhlenino toroue:
is-zsi{.m (i.5-2.3 m'ks' 11-17 finb)
B - 1 0