| 1. Check a condition of hoses and connections. |
| 2. Disconnect a vacuum hose from the coal filter and connect the vacuum manometer. When the engine is not heated-up and idles, depression has to be absent. If depression is present probably the blowing-off valve is faulty. Warm up the engine and check depression existence. If is not present, replace the blowing-off valve. |
| 3. Check that the two-sided valve located near the coal filter did not pass air. |
| 4. Check giving of tension for the blowing-off valve. |
| 5. Check the coal filter for leak existence. |