After pulling in the air and fuel during the intake stroke the piston is now forced back up in the cylinder compressing that air and fuel mixture. So you squirt the tablespoon of engine oil into a cylinder that is reading low.
How To Do A Compression Test 15 Steps With Pictures Wikihow
How to do compression test. With a compression tester a few hand tools and 20 minutes you can try this yourself. Step 1 remove the fuel pump and fuel injection fuses. Cylinder compression can inform you on how much wear an engine has on. Double check that you disconnected the appropriate stuff so the engine doesnt actually start. The trouble is poor ring to bore sealing. Youre all set up now and ready to actually do the compression test.
When youre done check the compression gauge to get the test result. If the compression comes up markedly. The engine will be running throughout the entire process. This is the stroke in which you will be performing the compression test. Now turn the key and crank the engine over for about 10 seconds. 40 psi or more.
Then retest the cylinder. The needle on the compression gauge will stay at the highest indicated compression reading. A compression test can also inform of an individual cylinder problem which can be repaired. Crank the engine two revolutions or so to spread the oil. Press the pressure release valve on the side of the gauge which will return the gauge to zero pressure for the next test. Turn the key as far as it will go in the ignition then release it.
Adding oil to spark plug hole for wet compression test. This mixture must be placed under pressure in order for the engine to create any power. Disconnect the main wire to the coil and spark plug. Do this about 4 or 5 times without shutting off the vehicle at all. Crank the engine at least 4 times to complete the test.
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