Compression Pressure Inspection

WARNING: This page is about a different variant/trim than selected.

NOTE: If the there is lack of power, excessive oil consumption or poor fuel economy, measure the compression pressure.

Start the engine until coolant temperature goes up to 80-95°C and stop the engine.
Remove the ignition coils.
(Refer to Engine Electrical System - " IGNITION COIL ")
Remove the spark plugs.
Using a 16mm plug wrench, remove the 4 spark plugs.

(Refer to Engine Electrical System - " SPARK PLUG ")

Check cylinder compression pressure

Insert a compression gauge into the spark plug hole

Courtesy of KIA MOTORS AMERICA, INC.

Fully open the throttle valve.
Measure the compression pressure after at least 20 rotations while cranking the engine with the throttle valve opened.
NOTE: Always use a fully charged battery to obtain engine speed of 200 RPM or more.
Repeat steps (1) through (3) for each cylinder.
NOTE: This measurement must be done in as short a time as possible.

Compression pressure:

1216.02 kPa (12.4 kgf/cm² , 176.37 psi)/200 - 250 RPM

Minimum pressure:

1068.93 kPa (10.9 kgf/cm² , 155.03 psi)
If the cylinder compression in 1 or more cylinders is low, pour a small amount of engine oil into the cylinder through the spark plug hole and repeat steps (1) through (3) for cylinders with low compression.
- If adding oil helps the compression, it is likely that the piston rings and/or cylinder bore are worn or damaged.
- If pressure stays low, a valve may be sticking or seating is improper, or there may be leakage past the gasket.
NOTE: The compression pressure standard/lower limit is based on the condition of a new engine and is not a judgment standard for a vehicle in operation.

Reinstall the spark plugs.
(Refer to Engine Electrical System - " SPARK PLUG ")
Install the ignition coils.
(Refer to Engine Electrical System - " IGNITION COIL ")
Some DTC's code may exist after the inspection test and may need to be manually cleared with KDS.