1. The test results of the compression pressure in the cylinders allow to determine the overall upper portion of the engine components (piston, piston rings, valves, cylinder head gaskets, etc.) and a qualitative estimate of the degree of wear. Most importantly, analysis of the resulting audit information allows you to narrow the range of possible reasons for the decline of compression in the cylinders, failure accurately tied to violations of specific components functioning well, whether the piston rings, valves, their seat or head gasket.  | The engine should be warmed up to normal operating temperature and the battery is fully charged. |
2. Start with cleaning candle niches (blow out with compressed air as a source which in this case is perfect ordinary bicycle pump). The main objective is to prevent the ingress of debris into the cylinders during the measurement.
3. Relieve the pressure in the fuel system (see chap. The power supply system and release). The fuel pump during the execution of the procedure is to be disabled.
4. Turn the engine all the spark plug (see chap. Adjustment and routine maintenance). Fix the throttle in the fully open position.
5. On models equipped with the ignition distributor, remove the lid from the last central (coil wire) and ground it in the engine block. On models without a distributor, disconnect the wiring from each of the ignition coils.  | 6. Set compression gauge into the spark plug hole of the first cylinder. |
7. Turn the engine at least seven cycles and read the meter. On the serviceable engine pressure should accrue quickly. Low pressure in the first cycle, accompanied by a gradual increase of its future, speaks about deterioration of piston rings. If the shaft is turned further pressure does not rise, it can be regarded as evidence of leaks of valves or infringement of tightness of the cylinder head gasket (not excluded as the likelihood of cracks in the head). The accumulation of deposits on a working facet of the valve plates can also reduce the compression pressure. Record the maximum reading compressometer.
8. Repeat for the remaining cylinders of the engine. Compare the results with regulatory requirements (see. Specifications).
9. At excessively low results of measurements, fill in each of the cylinders through the spark plug hole a little motor oil (two to three teaspoons) and repeat the test.
10. If the addition of oil leads to increased pressure, it speaks about deterioration of piston rings. If the compression does not increase, the reason for its decline are leaks of valves or infringement of tightness head gasket. Leaking valves can be associated with a burn-out of their seats, or deformation / burn-out or mechanical damage working facets.
11. If the compression pressure is equally underestimated in two adjacent cylinders, it is highly probable that we can talk about breakage head gasket within its bridges between the cylinders. The presence of coolant in the engine oil will confirm this assumption.
12. If the pressure in a cylinder about 20% lower than in the other, and this is accompanied by a violation of the stability of the idle speed should assess the degree of wear of the respective valve drive cams on camshaft.
13. Unusual overstatement of the compression pressure is usually caused by excessive carbon formation in combustion chambers. In this case, the cylinder head must be removed for the purpose of decarbonization.
14. At excessively low results of measurements, as well as in case of violation of the uniformity of the pressure distribution between the cylinders will be useful to test the engine for leaks in the workshop car service. This check will accurately identify the source of the leak and assess the degree of its severity. |
