1. Results of check of kompressionny pressure in cylinders allow to define the general condition of components of the top part of the engine (pistons, piston rings, valves, laying of a head of cylinders, etc.) and qualitatively to estimate degree of their wear. That is especially important, the analysis of information received as a result of check allows to narrow a range of the possible reasons of falling of a compression in cylinders, rather precisely having adhered refusal to violations of functioning of quite concrete components, whether it be piston rings, valves, their saddles or head laying.
The engine should be heated-up to normal working temperature, and the storage battery is completely charged.
2. Begin with pro-cleaning of candle niches (blow them the compressed air as which source in this case the ordinary bicycle pump perfectly will approach). The main objective is prevention of hit of garbage in cylinders during performance of measurements.
3. Dump pressure in a power supply system (see. Head of the Power supply system and release). The fuel pump in the course of performance of this procedure should be disconnected.
4. Turn out from the engine all spark plugs (see. Head of Control and routine maintenance). Fix a butterfly valve in completely open situation.
5. On the models equipped with the distributor of ignition, disconnect from a cover of the last central (a bobbin wire) and earth it on the engine block. On models without the distributor disconnect electroconducting from each of ignition coils.
6. Establish компрессометр in a candle opening of the first cylinder.
7. Turn the engine at least on seven steps and consider the measuring instrument indication. On the serviceable engine pressure should accrue quickly enough. Low pressure on the first step, being accompanied its gradual increase on the subsequent, speaks about wear of piston rings. If at a further provorachivaniye of a shaft pressure does not rise, it can be regarded as the certificate of leakages of valves or violation of tightness of laying of a head of cylinders (the probability of existence of cracks in a head is not excluded also). The congestion of deposits on working facets of plates of valves also can lead to decrease in kompressionny pressure. Write down the maximum indication компрессометра.
8. Repeat procedure for the remained cylinders of the engine. Compare results to standard requirements (see. Specifications).
9. At excessively low results of measurement, fill in in each of cylinders through a candle opening of a little impellent oil (two-three teaspoons) and repeat check.
10. If addition of oil leads to pressure increase, it speaks about wear of piston rings. If the compression does not increase, the reason of its decrease are leakages of valves or violation of tightness of laying of a head. Leakages of valves can be connected with a burn-out of their saddles, either a deformation/burn-out or mechanical damages of working facets.
11. If pressure of compression is equally underestimated in two next cylinders, with high degree of probability it is possible to speak about violation of integrity of laying of a head within its crossing point between these cylinders. Presence of cooling liquid at impellent oil will confirm this assumption.
12. If pressure in one of cylinders approximately for 20 % is lower, than in other and it is accompanied by violation of stability of turns of idling, it is necessary to estimate degree of wear of cams of a drive of the corresponding valves on a camshaft.
13. Unusual overestimate of kompressionny pressure usually is a consequence of an excessive nagaroobrazovaniye in combustion chambers. In this case the head of cylinders should be removed for the purpose of carrying out a dekarbonizatsiya.
14. At excessively low results of measurements, and also in case of violation of uniformity of distribution of pressure between cylinders it will be useful to hold testing of the engine for leaks in the conditions of a car-care center workshop. Such check will allow to define precisely a source of leak and to estimate degree of its gravity.