Engine Compression Test

Steps to testing the compression
Remove ignition leads
Remove spark plugs
Insert hose from the compression tester into the spark plug hole.
crank the engine for 5 seconds with foot flat
write down the reading of compression test
do the same test on the same cylinder but with a little bit of oil on the piston head, this is called a wet test
crank the engine again for 5 seconds
write down the reading of compression test
do the same for the next cylinder
if there is a 10 - 15% difference between cylinders there is a problem with the cylinder


Safety precautions
disconnect the ignition system
turn off injectors
do not drop spark plugs
do not insert hose further into the cylinder than what the spark plug would sit