How to Test Engine Cylinder Compression?
2 Answers
Before measuring cylinder compression, remove all spark plugs and place the reset-to-zero gauge probe into the spark plug hole of the cylinder being tested. Observe and record the value indicated by the gauge's first needle movement. Release the starter to reset the gauge needle to zero. Repeat the measurement. If inconsistent readings occur between measurements, lower values indicate the piston did not start during optimal intake and compression phases.
Testing engine cylinder pressure is actually quite simple. I've helped friends with it a few times using a compression tester. First, you need to warm up the engine to normal operating temperature to get accurate readings. Then, turn off the engine and disconnect the ignition wires or spark plugs. Remove the spark plug from each cylinder and screw in the compression tester adapter. Next, have someone turn the key to start the vehicle or use a tool to rotate the crankshaft while you monitor the gauge readings. Normally, cylinder pressure should be between 12 to 16 bar – values too low or too high indicate problems. If a cylinder shows insufficient pressure, it might be due to worn piston rings or leaking valves. In such cases, repair it early to avoid later issues like oil burning or power loss. Remember to reinstall the spark plugs after testing and keep the wiring tidy. Regular compression checks during maintenance can prevent costly overhauls.
