1. At decrease in efficiency of return of the engine, and also in case of admissions of ignition which do not manage to be tied to violations of functioning of systems of ignition and food, it is necessary to perform measurement of compression pressure in cylinders which analysis of results will allow to define the general condition of the engine. Regular performance of check of compression pressure will help to reveal symptoms of malfunctions in time and to prevent development of their reasons.
2. The engine has to be heated-up up to the normal working temperature, the battery is completely charged, all spark plugs are unscrewed (see the Head Routine maintenance). Also the help of the assistant will be required.
3. Cut off power system of ignition, having disconnected VV an ignition coil wire from a cover of the distributor and having grounded it on the block of cylinders (use a wire crossing point). On models without distributor of ignition disunite the electric socket on the ignition coil block in a forward part of a head of cylinders.
4. In order to avoid damage of the catalytic converter dump pressure in system of injection and disconnect a power supply system, having taken out the relay of the fuel pump (see the Head the Power supply system).
5. Connect компрессометр to a candle opening of the 1st cylinder (preferably to use the measuring instrument with a carving tip).
6. Ask the assistant to squeeze out against the stop a pedal of an accelerator and to turn the engine a starter. After the first two provorachivaniye of a bent shaft instrument reading has to reach the maximum value. Write down result.
7. Repeat measurement for the remained cylinders, write down results.
8. Pressure in all cylinders has to be almost identical ranging from 11 to 15 bars. The difference in indications exceeding value of 1.5 bars should be considered as a violation sign. Inadmissibly also lowering of compression pressure below 10 bars.
9. Remember that pressure in the serviceable engine has to rise quickly enough. The low indication on the first step with gradual increase it on the subsequent, speaks about wear of piston rings.
10. If pressure does not rise at all, it is necessary to check tightness of closing of valves and a condition of laying of a head of cylinders (also the probability of formation of cracks in a head is not excluded). The congestion of deposits on the lower surfaces of plates of valves can also cause loss of compression pressure.
11. If results of measurements appear below admissible value, it is necessary to try to define the reason of loss of pressure. The most elementary of checks is injection through a candle opening in the corresponding cylinder about one teaspoon of lubricating oil with the subsequent repetition of measurement of compression pressure.
12. If right after addition in the oil cylinder pressure of compression is temporarily restored, it is necessary to estimate degree of wear of pistons, walls of cylinders and piston rings. Otherwise, it is possible to tell about violation of tightness of closing of valves (for example, as a result of a progar) or damage of laying of a head of cylinders (or actually heads).
13. Equally low pressure in two next cylinders with big degree of probability demonstrates damage of the crossing point of laying of a head of cylinders located between them. Availability of cooling liquid in motive oil will confirm this assumption.
14. If pressure in one of cylinders is about 20% lower, than in the others, and stability of turns of idling of the engine is slightly broken, wear of a working ledge of the corresponding cam of the camshaft can be the reason of this phenomenon.
15. Excessively high compression pressure testifies to a strong nagaroobrazovaniye in combustion chambers. In this case the head should be removed and subjected to decarbonization.
16. In conclusion, screw candles, establish to the place of the relay of the fuel pump and put into operation system of ignition.