2. The engine must be warmed up to normal operating temperature, the battery must be fully charged. All spark plugs must be removed (see chapter 1). In addition, you will need an assistant for this work.
3. Remove the fuel pump fuse (located in the fuse box in the passenger compartment), and if possible, start the engine to work out any remaining fuel in the system. Failure to do so may damage the catalytic converter.
4. Install the compression tester in the spark plug hole of the 1st cylinder. A compression gauge that is screwed into the threaded hole of the spark plug is more preferable.
5. Ask the assistant to fully depress the accelerator pedal and turn on the starter. After one or two revolutions of the crankshaft, the pressure in the cylinder should increase to a maximum, after which its value will stabilize. Record the maximum meter reading.
6. Repeat the test for all other cylinders and record the pressures in each of them.
7. Pressure readings in different cylinders should be close in value. The maximum difference between any two cylinders must not exceed 2 bar. Keep in mind that a healthy engine should build pressure quickly. Low pressure during the first stroke followed by a gradual increase in subsequent strokes indicates worn piston rings. If the pressure is low after the first stroke and does not increase on subsequent strokes, this indicates leaks through the valves or through the head gasket (the reason for this may also be damage to the block head itself). The presence of deposits on the undersides of the valve heads can also cause low pressure.
8. Recommended compression pressures are listed in Technical Data.
9. If the pressure in one of the cylinders is reduced, perform an additional check to find out the reason for this. Pour a little clean oil into such a cylinder through the hole of the candle (about a teaspoon) and recheck.
10. If a temporary increase in pressure occurs when oil is added, this indicates excessive cylinder or piston wear. If the pressure does not rise, this means that the cause may be leaks through burnt valves or through the head gasket.
11. Low pressure in two adjacent cylinders almost certainly indicates leakage through the gasket in the area between them. The presence of coolant in engine oil is a confirmation of this assumption.
12. Reduced pressure in one of the cylinders by approximately 20% relative to the other cylinders, as well as not quite smooth engine idling, can be caused by wear on the camshaft cam.
13. If the pressure is unusually high, carbon deposits in the combustion chamber may be the cause. In this case, the cylinder head must be removed and cleaned.
14. At the end of the test, screw in the candles (see chapter 1) and insert the fuel pump fuse.