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Compression check in cylinders
Compression (pressure at the end of the compression stroke) in the cylinders - a key indicator for the diagnosis of the condition of the engine without disassembling. According to its average value and the difference in the values of individual cylinders can reliably determine the degree of general wear and tear connecting rod and piston engine, troubleshoot this group and valve train parts. Check the compression of a special device - Compression, which currently can be easily obtained in large auto parts stores.
NOTE It looks like compressometer used to illustrate the book. There are options for Compression, which instead of a threaded fitting for the screwing instead of spark plugs installed rubber tip. Such compressometer checking compression simply strongly pressed against the spark plug hole. |
A WARNING An important condition for correct readings when testing compression is a bad starter and electrical circuits, as well as a full battery charge. |
1. Start the engine and warm it up to normal operating temperature. | | | 3. Disconnect the low-voltage wiring harness from the ignition coil, thereby turning off the ignition system. |
A WARNING Cranking the engine disconnected at the tips of high-voltage wires and Failure to disconnect the ignition coil can lead to a breakdown of its high-voltage circuit. |
| | 4. Disconnect the fuel pump by removing the fuse ?��11 ... | |
6. Replace the spark plug hole in the cylinder checked compressometer. 7. Press the accelerator pedal fully to fully open the throttle. 8. Include a starter and turn them to the crankshaft of the engine as long as the pressure in the cylinder is no longer increasing. This corresponds to approximately four cycles of compression.
NOTE For correct reading compressometer crankshaft must rotate at 180-200 min -1 or above but not exceeding 350 min -1. |
| | 9. Writing compression tester readings ... | 10. ... set his hand to zero by pressing the air release valve. |
NOTE In a different design Compression readings can be reset by other means in accordance with the instruction to the device. |
11. Repeat steps. 6-10 for the other cylinders. The pressure should not be lower than 1.0 MPa and not be different in different cylinders of more than 0.1 MPa. The lowered compression in separate cylinders can result from a loose fit valves in the saddle, damaged cylinder head gasket, broken, or sticking piston rings. The lowered compression in all cylinders indicates wear of the piston rings. 12. To clarify the reasons for the lack of compression fill the cylinder with low compression of about 20 ml of engine oil and re-measure compression. If the reading compressometer increased, most likely the fault of the piston rings. If the compression remains unchanged, then the valve plate loosely fitting to their saddles or damaged cylinder head gasket.
HELPFUL ADVICE Due to insufficient compression can be explained as a compressed air into the cylinder, where the piston is pre-set at TDC compression stroke. To do this, remove the tip of the compression tester and connect it to the compressor hose. Insert tip into the spark plug hole into the cylinder and apply air pressure of 0.2-0.3 MPa. To the crankshaft of the engine is not cranked, including higher transmission and brake the car a lay brake. The output (drain) of air through the throttle device indicates leakage of the intake valve and exhaust through - on the leaking exhaust valve. If damaged cylinder head gasket air will escape through the neck of the expansion tank in the form of bubbles or the neighboring cylinder, which is detected by the characteristic hissing sound. |
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