Compression Inspection
WARNING:
- When the engine and the oil are hot, they can badly burn. Turn off the engine and wait until they are cool.
- Verify that the battery is fully charged.
- Recharge it if necessary. (See BATTERY RECHARGING .)
- Warm up the engine to the normal operating temperature.
- Perform "Fuel Line Safety Procedure". Leave the fuel pump relay removed. (See FUEL LINE SAFETY PROCEDURE .)
- Remove the ignition coils. (See IGNITION COIL REMOVAL/INSTALLATION .)
- Remove the spark plugs.
- Install the compression gauge into the spark plug hole.
- Crank the engine a minimum of five compression strokes and record the highest reading. Note the approximate number of compression strokes required to obtain the highest reading.
- Repeat the test on each cylinder, cranking the engine approximately the same number of compression strokes.
- The indicated compression pressures are considered within specification if the lowest reading cylinder is within 75%
of the highest reading.
- If the compression in one or more cylinders is low or the compression difference between cylinders exceeds the maximum, pour a small amount of clean engine oil into the cylinder and recheck the compression.
- If the compression increases, the piston, the piston rings, or cylinder wall may be worn and overhaul is required.
- If the compression stays low, a valve may be stuck or improperly seated and overhaul is required.
- If two adjacent cylinders indicate low compression pressures and squirting oil on piston does not increase compression, the head gasket may be leaking between cylinders. Engine oil and/or coolant in the cylinders could result from this condition.
- Remove the compression gauge.
- Install the spark plugs.
Tightening torque
- 9-20 N.m {91-204 kgfcm, 79-177 inlbf}
- Install the ignition coils. (See IGNITION COIL REMOVAL/INSTALLATION .)
- Install the fuel pump relay.