Operation CHARM: Car repair manuals for everyone.
Home >> Subaru >> 1989 >> Hatchback 2WD F4-1781cc 1.8L SOHC >> Repair and Diagnosis >> Maintenance >> Tune-up and Engine Performance Checks >> Compression Check >> Testing and Inspection
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

Or, hide this message: temporarily or permanently

Compression Check: Testing and Inspection

Engine Compression
When checking compression pressures, ensure engine is at normal operating temperature then install a suitable compression gauge. Crank engine and note compression gauge reading when gauge pointer is steady.

Procedure
1. After warming up the engine, turn off the ignition-starter switch.
2. Make sure that the battery is fully charged.
3. Remove all the spark plugs.
On MPFI model, disconnect the harness connectors for injectors.
On SPFI model, disconnect the harness connector for injector.
4. Fully open the throttle valve.
5. Check the starter motor for satisfactory performance and operation.
6. Crank the engine by means of the starter motor, and read the maximum value on the gauge when the pointer is steady. Hold the compression gauge tight against the spark plug hole.
7 Perform at least two measurements per cylinder, and make sure that the values are correct.






Difference between cylinders: 196 kPa (2.0 kg/cm2, 28 psi) or less.
pro multis · About Operation CHARM