2. The engine must be warmed up to normal operating temperature, the battery must be fully charged. The spark plug weight must be unscrewed (see Chapter 1). In addition, you will need an assistant for this work.
3. Disconnect the ignition system. To do this, disconnect the ignition coil connector or the ignition module connector. Also remove fuse #14 to disconnect the fuel pump.
4. Install the compression gauge into the spark plug hole of the 1st cylinder. A compression gauge that screws into the threaded spark plug hole is preferable.
5. Ask an assistant to fully depress the accelerator pedal and turn on the starter. After one or two revolutions, the pressure in the cylinder should increase to the maximum, after which its value will stabilize. Record the maximum reading on the device.
6. Repeat the test in all other cylinders, recording the pressure values in each of them.
7. The pressure readings in different cylinders should be close in value and meet the technical requirements. Keep in mind that in a serviceable engine, the pressure should increase quickly. Low pressure in the first stroke followed by a gradual increase in subsequent strokes indicates wear of the piston tracks. If the pressure value is low after the first stroke and does not increase in subsequent strokes, this indicates leaks through the valves or through the cylinder head gasket (damage to the cylinder head itself may also be the cause). The presence of deposits on the undersides of the valve plates can also cause low pressure.
8. If the pressure in one of the cylinders is low, perform an additional check to determine the cause. Pour a little clean oil (about a teaspoon) into such a cylinder through the spark plug hole and repeat the check. If the pressure temporarily increases when adding oil, this indicates excessive wear of the cylinder or piston. If the pressure does not increase, then the cause may be leaks through burnt valves or through the cylinder head gasket.
9. Low pressure in two adjacent cylinders almost certainly indicates a leak through the gasket in the area between them. The presence of coolant in the engine oil confirms this assumption.
10. At the end of the check, install the spark plugs. Restore the connection of the ignition system and the fuel pump.
(This article is a copy from the website: FORDBOOK.ru)