Hyundai Tucson: Engine Mechanical System / Repair procedures

- Compression Pressure Inspection

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

1.Start the engine until coolant temperature goes up to 80-95°C and stop the engine.

2.Remove the spark coils.(Refer to Engine Electrical System - "Spark Coil")

3.Remove spark plugs.Using a 16mm plug wrench, remove the 4 spark plugs.

4.Disconnect the injector connector (A).

5.Check cylinder compression pressure

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

(2)Fully open the throttle valve.

(3)Measure the compression pressure after at least 20 rotations while cranking the engine with the throttle valve opened.

• Always use a fully charged battery to obtain engine speed of 200 rpm or more.

(4)Repeat steps (1) through (3) for each cylinder.

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

Compression pressure :1559.25 kPa (15.9 kgf/cm² , 226.15 psi)Minimum pressure :1412.15 kPa (14.4 kgf/cm² , 204.82 psi)Difference between each cylinder :98.07 kPa (1.0 kgf/cm², 14.22 psi) or less

(5)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.

6.Install ignition coils.(Refer to Engine Electrical System - "Spark Coil")

7.Some DTC's code may exist after the inspection test and may need to be manually cleared with diagnostic tool.