1. Check the oil level in the engine, the condition of the battery and starter.
2. Start the engine and warm it up to a temperature of 80-90°C.
3. Loosen the fuel line nuts and disconnect the fuel lines from the injectors.
4. Remove the ramp and unscrew all 4 nozzles.
5. Set the engine speed on the pressure gauge.
6. Place the pressure gauge adapter into the nozzle hole
7. Scrolling the engine with a starter at a fully open air damper, take the readings of the pressure gauge. The standard compression value at 250 rpm is 1920 kPa, the difference in values between the cylinders is no more than 300 kPa.
8. If the compression value in one of the cylinders or its difference relative to other cylinders is not normal, pour a small amount of engine oil into the cylinder through the nozzle hole and repeat the measurements.
9. If the compression increased after filling with oil, this indicates an increase in the gap between the piston rings and the cylinder mirror due to their wear. If the compression value remains the same, the cause is a loose fit of the valves or a poor seal between the cylinder block and the block head.