Compression Check: Testing and Inspection

1. Warm engine to normal operating temperature, then turn off engine.
2. Remove one spark plug per cylinder and disconnect ignition coil connector.
3. Connect a compression gauge to No. 1 spark plug hole.
4. Fully depress accelerator pedal and crank engine, record maximum gauge reading.
5. Repeat steps 3 and 4 for each cylinder.
6. Minimum pressure is 101 psi. Lowest compression reading should be within 75% of highest compression reading.
7. If compression in one or more of the cylinders is low, pour a small amount of engine oil into cylinder and recheck compression. Check results as follows:
a. If compression increases, piston, piston rings, or cylinder wall may be worn.
b. If compression stays low, valve may be stuck or improperly seated.
c. If compression in adjacent cylinders stays low, cylinder head gasket may be defective or cylinder head distorted.
8. Connect ignition coil, then apply suitable anti-seize compound to spark plug threads and install plugs. Torque plugs to 11-17 ft. lbs.