Engine On-Vehicle Inspection; Compression - Mazda 626 MX-6 Workshop Manual

Possible Cause
ON-VEHICLE INSPECTION
If the engine exhibits low power, poor fuel economy,
or poor idle, check the following:
1. Ignition system (Refer to Section 5)

2. Compression

3. Fuel system (Refer to Section 4)
COMPRESSION
1. Check that the battery is fully charged. Recharge
it if necessary.
86U01X-019
2. Warm up the engine to the normal operating tem­
perature.
3. Turn it off for about 10 minutes to allow the exhaust
manifold to cool.
4. Remove all spark plugs.
5. Disconnect the primary wire connector from the
ignition coil.
86U01X-020
6. Connect a compression gauge to No. 1 spark plug
hole.
7. Fully depress the accelerator pedal and crank the
engine.
8. Note the maximum gauge reading.
9. Check each cylinder.
Compression pressure
Turbo
Non-Turbo 1,120 (11.4, 162)—270
86U01X-021
ON-VEHICLE INSPECTION
kpa (tg)cm,
Standard
960 (9.8, 139)—260 680 (6.9, 98)—260
780 (8.0, 114)—270
1
Minimum
86U01X-022
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