Compression Testing Activity Note:
This test is done with a conventional gauge. RECORD ALL READINGS BELOW
1.
Remove the spark plug from one of the 4 cylinders that were used for the static test.
2.
Remove the Schrader valve from the compression gauge.
3.
Screw the compression gauge into the spark plug hole.
4.
Ground the spark plug wire, or unplug the coil for coil near plug engines, and disconnect the fuel injector.
5.
Start the engine.
6.
Record the gauge reading at maximum sweep of the needle below. To see the maximum sweep of the needle, use a piece of paper to cover the gauge face through the center of the gauge and rotate the paper until the needle disappears. Then back the paper up until the needle reappears. (pivot the paper around the center of the gauge)
7.
Turn off the engine.
8.
Remove the compression gauge, reinstall the spark plug and wire, and connect the fuel injector.
9.
Repeat steps 1-8 for the 3 more cylinders. Use the same 3 cylinders that were used for the static compression test. Allow a 10 percent variance from the highest to the lowest cylinder.
Running Compression Readings
Cyl. # 1
_______ psi
Cyl. # 3
_______ psi
Cyl. # 2
_______ psi
Cyl. # 4
_______ psi
10
