How to Perform a Compression Test on the Engine in a Kia Spectraby Contributor
When the 4-cylinder engine in the Kia Spectra runs poorly, burns oil or loses power, an easy way to diagnose the problem is a compression test. This allows you to find out what is happening inside the engine without going through the troublesome process of tearing it apart. A compression test indicates when parts wear out, such as the cylinder wall, pistons and rings.
Begin by warming up the engine. Performing the compression test while the engine is cold will produce inaccurate results. The battery must also be in good condition so that it can spin the engine several times during the test.
Turn off the engine before continuing. Disable the ignition system to avoid electrical shock and remove all four spark plugs from the engine. It can now spin freely.
Test the first cylinder by placing the compression tester in the spark plug hole and cranking the starter. This rotates the engine and builds compression in that cylinder. Keep a record of each of the compression numbers for comparison later on.
Repeat this procedure, testing all four cylinders of the Kia Spectra. The resulting compression numbers should be similar, falling within 10 PSI of each other. Any cylinders with a low reading need to be retested, since there are problems in that cylinder.
Compare the test results to manufacturer specifications for the Kia Spectra. If the model year is 2005-2008, the compression ratio is 10.1:1. If it is 2002-2004, the ratio is 9.5:1. For model years 2000 and 2001, the ideal ratio is 10.0:1. Results from the compression test should fall within 15 PSI of these numbers.
Add a little motor oil to any cylinders that have a low compression number and perform the test again. If this causes the number to increase, the cylinder walls or piston rings are in need of repair. If this doesn't affect the number, the valves or valve seats need repair.