Cylinder compression pressure test-engine maintenance basis

The engine is at normal temperature.

Disconnect the spark plug

Disconnect the fuel injector.

full throttle

Measure the compression pressure readings for at least 5 strokes.

Analysis of cylinder pressure test results;

Blood pressure is normal

high atmospheric pressure

be lax

Main reasons for low cylinder pressure:

Valve leakage

Wear of piston, piston ring, cylinder and cylinder gasket

Cylinder leakage test

Test conditions:

Make the engine reach the normal working temperature.

Place the test cylinder at the top dead center of the compression stroke. So as to ensure that the intake valve and the exhaust valve are in the closed position.

Open the radiator cover to prevent damage to the cooling system.

Cylinder pressure leakage diagnosis table

situation

probable cause

The throttle body leaks air.

The intake valve is bent, ablated or poorly seated.

The exhaust pipe is leaking.

Exhaust valve is bent, ablated or improperly installed.

Air radiator leaks

Leaks or cracks in the cylinder gasket appear in the cylinder head and cylinder block.

The leakage between adjacent cylinders exceeds 50%.

The cylinder head and cylinder block are leaking or the cylinder liner between adjacent cylinders is broken.

More than 25% of the leakage can only be carried out from the open oil filler.

The piston ring is stuck or broken; Piston cracking; Wear of piston ring and/or cylinder wall