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Diagnostics of the engine with the help of the gauge
Measurement of dilution is reliable and relatively cheap way to diagnose the engine. According to the testimony vakuumetry can get an idea about the state of the piston group of tightness gaskets of the cylinder head, intake and exhaust manifold, the correct adjustment of the power of the engine and the exhaust capacity of the exhaust gas condition of valves (them is stuck or burning) and valve springs, as well as check the correct adjustment of the moment of ignition and preservation of phases timing during engine operation. Unfortunately, Vacuum gauge readings difficult to interpret and analyze the results of readings may be erroneous, therefore, vacuum diagnostics it is advisable to combine with other methods. Initial factors on which indications vakuumetry analyzed and made the most accurate conclusions about the state of the engine is the absolute instrument reading and character of movement of the instrument pointer (dynamics of indications). The scale of most Vacuum gauge is scaled in millimeters. Hg. column. With increasing dilution (and accordingly pressure drop) the instrument reading increases. For every 300 m above sea level absolute indications Vacuum gauge will vary by approximately 25 mm Hg Vacuum gauge attach directly to the intake manifold, but not to other openings through which a vacuum is separated from the manifold channel of a certain length (for example, before the throttle openings). Before the beginning of tests completely warm up the engine. Block the wheels and set the parking brake. When you position the gear lever in neutral (or in position Park on cars with automatic transmission) start the engine and leave to idle.
A warning  Before starting the engine, carefully check the condition of the fan (presence on them of damages or cracks). During operation, the motor does not bring your hands too close to the fan, hold the device at a sufficient distance from the fan, and do not stand in line with the rotating impeller.
Check the vacuum gauge. On the serviceable engine Vacuum gauge should show depression 430-560 mm Hg, and the needle should be almost immobile. The following is a description of the nature Vacuum gauge readings and methodology for determining the condition of the engine based on them. | PERFORMANCE ORDER | | 1. Too low vacuum level usually indicates gaskets between the suction manifold and the throttle chamber, a vacuum hose, as well as too late or incorrect ignition time of opening and closing valves. Before removing the cover of a gear belt and check the combination of adjusting labels check up installation of ignition by a stroboscope and eliminate all other possible causes, guided test procedures described in this chapter. | | 2. If the reading on the vacuum gauge 75-200 mm Hg below normal and are unstable (the arrow twitches) it indicates a leak in the lining of the inlet suction manifold or a faulty injector. | | 3. If the arrow regularly deviates on 50-100 mm Hg, the cause is a leak valve. To confirm this conclusion, check the engine compression. | | 4. The arrow irregularly deviates towards low indications, or twitching shows low depression. The probable cause is the increased resistance to movement of valves, or disruptions in the cylinder. Check the compression in cylinders and examine candles. | | 5. If idling the arrow quickly fluctuates within 100 mm Hg, and the operation of the engine is accompanied by smoke from the muffler, the worn valve guides. To verify this conclusion, it is necessary to conduct tests of chambers of combustion for tightness (with air pump). If the arrow quickly fluctuates at the same time an increase in engine speed, it is necessary to check the tightness of the intake manifold gasket, elasticity of the valve springs. Such evidence may also be caused by a burn-out of valves and faults in work of cylinders (ignition failures). | | 6. Weak fluctuations arrows (within 20-30 mm.rt.st.v both sides) indicate an unstable work of ignition. Check out all the provided installation and adjustment, if necessary, connect the analyzer to the engine ignition system. | | 7. For large fluctuations arrow check up a compression in the cylinders, and tested for leaks, as reasons for failure can be broken cylinder or infringement of tightness of the cylinder head gasket. | | 8. If readings slowly vary over a wide range, check the cleanliness of pipelines PCV, correct adjustment of the fuel mixture, the hermetic seal of the throttle body or intake manifold. | | 9. Sharply open throttle, and when the engine speed is reached in 2500 rev / min release valve. The damper should slowly return to starting position. Vacuum gauge readings should fall almost to zero, then increase and exceed the control indications corresponding to stationary idling approximately 125 mm Hg, then depression should be restored at the same level. If depression is restored slowly, and at sharp opening valves controlling excess evidence is missing, the reason may be the wear of piston rings. At extremely slow restoration of depression check up cleanliness of a final path (as a rule the muffler or catalytic converter). The easiest way to check this is the opening of the exhaust duct to the suspicious areas and to repeat the test. |
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