How to do compression test in simple way

What is compression test?

·         The cylinder compression tester measure cylinder compression while the starting motor cranking the engine.

·         The compression tester is a pressure gauge that measure the amount of pressure and compression build up in the cylinder during the compression stroke.

Procedure

1.       Disconnect the main wire to the coil and spark plug wires remove spark plugs to conduct the compression test.

2.       Before removing the spark plug be sure the engine is at normal operating temperature and the battery is fully charged.

3.       Use the compressed air to blow any dirt out of the spark plug well.

4.       Remove the spark plug. Block the throttle wide open so the maximum amount of air enters the cylinder.

5.       Thread the compression tester adapter into the spark plug hole of cylinder -1

6.       The needle on the compression tester should show the reading of cylinder.

7.        Then test the rest of cylinder. Compression reading are usually considered as normal if the lowest reading is 75PSI and if engine compression pressure is 120PSI then all cylinder should have compression reading of 90PSI or higher.