Compression Check: Testing and Inspection

1. Warm engine to normal operating temperature, then turn off engine.
2. Remove all spark plugs and disconnect ignition coil connector.
3. Connect a compression gauge to No. 1 spark plug hole.
4. On Pickup models with 2.3L/4 - 140 engine and 2 spark plugs per cylinder, replace 1 spark plug in cylinder to ensure proper compression reading.
5. Fully depress accelerator pedal and crank engine, record maximum gauge reading.
6. Repeat steps 3 and 4 for each cylinder, compression pressure should be 142 - 185 psi. with a maximum variation between cylinders of 28 psi.
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.lb.