Vacuum diagnosis

The measurement of vacuum in the intake manifold is one of the most effective methods of diagnosis engine. The vacuum or negative pressure is a "negative" pressure, whose value is below atmospheric pressure. The negative pressure in the combustion chamber and intake manifold is formed during the piston down into the intake stroke, and its total value consists of consecutive (in order of the cylinders) pulses generated by each cylinder in turn. Timing the engine selected in such a way that individual pulses of each cylinder practically merge into a single, continuous stream of dilution due to which the carburetor in diffusers force appears, mixing air and petrol and engulfing the working mixture in the combustion chamber of each cylinder. In addition, the power vacuum is used to activate a variety of complementary mechanisms, which are located in the engine compartment or in the car. Different engine trouble, carburetor, ignition system and exhaust system muffling lead to a decrease in the vacuum or the appearance of its pulsation in the intake manifold. Any fault that affects the magnitude of dilution of the engine, will also affect the total amount of air flowing into each cylinder. This, in turn, affect the power and engine efficiency as well as disrupted additional vacuum mechanisms. To measure the dilution used a simple vacuum gauge, which is connected via a rubber tube to any branch pipe to the carburetor or intake manifold, which is constant (at routine motor) there is a vacuum. The diameter of the inner sleeve openings must not be less than one millimeter. Nipple on the intake manifold must be located at a distance equidistant from all the inlet valves. If the connection point closer to any of the intake valves, the pressure gauge begins to capture the pulse of the nearest cylinder, and it will make an error in reading. The best option to connect a vacuum gauge to the carburetor or on the nipple on the intake manifold, which is designed to supply vacuum to the air heating system. On cars "Satellite", "Samara" and other vacuum gauge is included in the original equipment and set (called econometrics) on the dashboard instrumentation. Drivers of these vehicles is offered during the movement to support the arrow in the green econometrics. This means economical driving without a sharp pressing the gas pedal. With a sharp arrow is pressed on the gas goes into the yellow or red sector and it shows on the fall of the vacuum in the intake manifold. Driving in this mode requires a lot of gasoline. Units in which the scale is calibrated to your pressure gauge, in principle, are not significant. Before the diagnosis should "calibrate" your device on several serviceable engines, remember to manometer. To warm the engine with good idle speed vacuum value is almost constant. The value of deflection for different engines can be different, depending on the number of revolutions and engine condition. The higher the value of vacuum at idle speed, the better the condition of the engine. When you open the throttle on the engine size proper dilution drops sharply and then begins to climb up to a value that is higher than the values ??of the dilution idle. After the closing of the throttle value dilution is gently lowered to a value that was at idle. There are faults that make it impossible to climb the value of dilution by increasing the angle of the throttle valve. When in a smooth increase in the angle of the flap opening observed uniform decrease power vacuum while reducing engine revolutions, it can mean the following faults: a significant blockage of exhaust gas switch fault in the electronic ignition system, improper installation belt timing. Strong rhythmic vibration arrows at the idling speed indicative of a thermal gap adjustment or the valves may be a problem in the valve drive mechanism. Strong pulsation vacuum suggests that disturbed motor pumping effect, disrupted the flow of constant dilution. Such an effect may give: Reduced clearances on the valves, valve stem sticking to the guide (especially after the repair head), high blood pressure in the oil system of hydraulic disrupts gap on the valves, the size of the hydraulic lifters and the valves no longer close, strong burnout valve or seat also has the effect of fluctuations in the vacuum idle. Adjusting the carburetor in the presence of fluctuations in the vacuum motor is warmed up - is ineffective and premature. Significant air leak under the carburetor or intake manifold leak breach is accompanied by a floating idle. The arrow shows the vacuum gauge smooth change in the intake manifold vacuum. Increased speed causes an increase in power vacuum, lowering the speed decreases the power vacuum. Such manometer indicates the following faults: a damaged gasket or a rubber pad under the carburetor, throttle axle wear, partial clogging of the fuel jet idling or violation of its threaded fasteners, loose closing of the throttle the second chamber, sealing gasket between the violation of the intake manifold and cylinder head . broken or loose vacuum hose, tightness of vacuum brake booster. Adjusting the carburetor in the presence of air leaks - a meaningless exercise. There are triple-carburetor in which to open the throttle of the second camera is used the vacuum actuator. The magnitude of the dilution and the time of its occurrence in the channel vacuum actuator can be controlled with a vacuum gauge. The work of the vacuum regulator ignition engine at various speeds is also possible to control this device. If during the adjustment of the carburetor or engine diagnostics, along with other appliances constantly use vacuum gauge, then after a short time you will learn to identify such faults that other experts do not notice. Indications vacuum gauge a broader range of tests, and it improves the quality of diagnosis and facilitates troubleshooting.