1. Compression gives an idea of the condition of the engine. The test results show, by way of valves and whether the pistons (piston ring), or whether they are worn. In addition, test results permit to decide whether to replace the engine, whether it is sufficient or complete renovation to replace the cylinder head gasket. To verify the required compressometer that for petrol engines available in specialty stores at an affordable price.  | Attention! For diesel engines Compression needs to limit measurements to about 40 atm. |
2. The engine must be at operating temperature, battery - fully charged. You will also need the help of an assistant.
3. Remove the fuel pump fuse from the block located in the engine compartment (see Chapter Onboard electric equipment). Start the engine and wait until it stops. If the engine will not start, crank the starter for about 10 seconds.
4. To gain access to the spark plugs, remove the oil filler cap and remove the plastic engine cover. Replace the cover.
5. Turn off the ignition system by disconnecting the plug from the ignition coil. Remove all spark plugs (Refer to Section Check and replacement of spark plugs. Check the status of high-voltage wires).
6. Set compression gauge into the spark plug hole of the first cylinder. It is desirable to use compression tester, the tip of which is wrapped in a spark plug hole.
7. Ask the assistant to hold the accelerator pedal is fully depressed and turn the starter. After several cycles of compression in the cylinder reaches a maximum value and not changed. Record result.
8. The maximum permissible pressure difference in the individual cylinders can be 3.0 atm. (for diesel engines of 5.0 atm.).
9. Compression in the serviceable engine is growing very fast. Low value shown after the first cycle, increases with subsequent cycles indicates the wear of piston rings. Low value after the first cycle does not increase after the next, indicating that any leaking valves or broken head gasket (the reason could also be a crack in the head). To decrease the compression may result in the presence of carbon on the valve plates.
10. It should be appreciated that due to the different speed at different starter models resulting measurement results may vary. The results obtained in the measurement of compression should be approximately the same for all cylinders.
11. If the pressure in any cylinder is at the minimum allowed, and even below, to determine the cause, follow these steps. Pour into the cylinder through the spark plug hole teaspoon of motor oil and repeat the measurement of compression.
12. If the addition of oil temporarily improved compression, the cause of her decline, most likely, is the wear of the piston rings or cylinder. If you increase the compression has occurred, it can be assumed that the reason - valve or a leak in a broken head gasket.
13. The low compression in two next cylinders almost certainly - a consequence of the breakdown of head gaskets. The presence of coolant in the combustion chamber or in the crankcase will confirm this assumption.
14. If the compression in one of the cylinders by approximately 20% lower than in the other, to the same idle speed is unstable, then the reason may be excessive wear of the cam camshaft.
15. Once validated, replace the spark plug (see Chapter Routine maintenance), put them tips of high-voltage wires, attach the connector to the ignition coil. Replace the plastic cover of the engine and the fuel pump fuse.
16. The values of compression pressure for the various engines are given in the specification. |
