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Diagnostic Tests produced using gauge
Depth measurement dilution provides valuable information about the state of internal engine components. There is an opportunity to assess the degree of wear of piston rings and cylinder walls, to identify leakage of the cylinder head and intake manifold, a violation of cross-exhaust system, jamming or burn-out valve, easing the valve springs, a violation of the ignition timing or the distribution operation of valves and other problems with the ignition . Unfortunately the results of testing of the vacuum easy to misinterpret, so it always should be done in conjunction with other checks, the overall analysis of the results which are inconclusive. For an adequate assessment of the situation is important as absolute indications of the vacuum gauge and the relative magnitude of the deviation of the instrument pointer. Most gauges measure the depth of the depression in mm (inches) of mercury (less than all of the results and indicators will be given in the metric system). All of the following references are based on assumptions about the inspection at zero altitude relative to sea level. Lifting points of examination (or reduced atmospheric pressure) leads to a corresponding reduction in the readings. To bind note that increasing the height of the point of the tests for each meter mark after 610 meters gives low results at 83 mm Hg. Art. Connect the gauge directly to the inlet connection of the inlet pipeline - not to the port of the throttle body. Make sure that no hoses during the inspection did not stay disconnected - it will lead to a breach of confidence in the results. Before you start checking, allow the engine to warm up fully. Lock (wedges) wheel and cock a lay brake. Translating transmission in position "P", start the engine and leave it running at normal idle speed.  | Before starting the engine, inspect the fan blades for cracks and other damage. Make sure that in the course of the procedure not to touch the fan and avoid contact with them vacuum hoses. After starting the engine should not become directly in front of a car or in the plane of rotation of the fan. |
Consider the testimony of the gauge; for reference, on average, serviceable engine should create a vacuum depth from 431 to 559 mm Hg. Art. When a stable position of the instrument pointer. The test results can be interpreted as follows: | - Stable low reading gauge usually indicates breakage gasket between the intake manifold and the throttle body, the presence of "leakage" of vacuum hoses, retarded ignition timing or distribution of violation of the valve mechanism (camshaft). With strobe check the ignition timing, and then spend all enumerated in this Chapter diagnostic check before proceeding to remove the cover of the distribution chain and validation of combining the distribution of labels.
- If the reading is below normal in the 75 - 200 mm Hg. Art. and stable at this level, the probability of leaks through a lining of the inlet pipeline in the area of the intake port or fuel injector failure.
- If the needle falls on the regular 75 - 100 mm Hg. Art. stably restrain on these values, it is possible to suspect a leak valve. Inspect compression pressure or leak testing of the engine.
- Irregular drop or reject the arrows can be caused by valve jamming or misfire. Inspect compression pressure and engine testing for leaks, and check the spark plug.
- Frequent jitter arrows at about 100 mm Hg. Art. when the engine is idling, followed by smoky exhaust speaks about worn valve guides. To confirm this assumption, make a test of the engine for leaks. If jitter occurs at higher engine speeds, check for leaks intake manifold gasket or cylinder head, evaluate the degree of weakening of the valve springs, make sure there are not burned valves and have there been misfiring.
- Minor fluctuations in the range of 25 mm upside-down can indicate a problem with the ignition. Perform all the usual settings, if necessary, start the engine to work with the analyzer ignition.
- In case of significant deviations make test compression pressure or leak testing of the engine to check the degree of wear or failure of the cylinder or head gasket integrity violations.
- If the needle gauge slowly "walks" in a wide range, check for blockage in the system is controlled crankcase ventilation (PCV), appreciate the quality of the fuel-air mixture and check for signs of leakage gasket throttle body / carburetor and intake manifold.
- Inspect for a slow recovery after reading "revival" of the engine by quickly opening the throttle and release it after the lifting of the engine speed of 2,500 rev / min. Typically, readings should fall almost to zero, to rise above the norm (about 130 mm Hg. V.), And then return to its previous value. If the depth of the vacuum recovered slowly and does not form a peak when closing the throttle, it is possible to speak about deterioration of piston rings. If there is a significant delay, check the patency of the exhaust system (often blocked muffler or catalytic converter). This assumption is the easiest way to check disunite section exhaust system above the alleged blockage.
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