Hyundai Kona: Engine Mechanical System / Repair procedures

Hyundai Kona (OS) 2018-2025 Service Manual / Engine Mechanical System / Repair procedures

Compession Pressure Inspection

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

1.	Start the engine and turn the coolant temperature to 80 - 95 °C and stop.

2.	Remove the engine cover. (Refer to Engine and Transaxle Assembly - "Engine Cover")

3.	Disconnect the injector extension connector (A) and the ignition coil connectors (B).

4.	Remove the ignition coils. (Refer to Engine Electical System - "Ignition Coil")

5.	Remove the spark plugs. Using a 16mm plug wrench, remove the 4 spark plugs. (Refer to Engine Electrical System - "Spark Plug")

Check the cylinder compression pressure.

(1)	Insert a compression gauge into the spark plug hole.

(2)	Set the throttle plate in the wide-open position.

(3)

While cranking the engine, measure the compression pressure.

•	Always use a fully charged battery to obtain engine speed of 250rpm or more.

(4)

Repeat step (1) through (3) for each cylinder.

•	This measurement must be done in as short time as possible.

Compression pressure

Standard : 1225.83 kPa (12.5 kg/cm², 177.79 psi) (200 - 250 rpm)

Minimum : 1078.73 kPa (11.0 kg/cm², 156.46 psi)

Difference between each cylinder :

98 kPa (1.0 kg/cm², 14 psi) or less

(5)

If the cylinder compression in one or more cylinders is low, pour a small amount of engine oil into the cylinder through the spark plug hole and repeat step 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.

7.	Install the spark plugs. (Refer to Engine Electrical System - "Spark Plug")

8.	Install the ignition coil. (Refer to Engine Electical System - "Ignition Coil")

9.	Connect the injector extension connector (A) and the ignition coil connectors (B).

10.	Some DTCs may exist after the inspection test and may need to be manually cleared with GDS.

Specifications

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