Audi A3

Since 1997 of release

Repair and car operation

Audi A3
+ The maintenance instruction
+ Current leaving and service
- The engine
   Compression check in engine cylinders
   Check of the engine by means of the vacuum gauge
   Removal and installation of the bottom cover of an impellent compartment
   Removal and engine/rkpp installation
   + Four-cylinder petrol engines 1.6, 1.8 l
   + Diesel engines
   + Major repairs
   + Greasing system
+ Systems of cooling, heating
+ The power supply system and release of the fulfilled gases
+ Engine electric equipment
+ Manual box of a gear change
+ Automatic transmission and models with a full drive
+ Coupling and power shafts
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment
+ Electroschemes

Check of the engine by means of the vacuum gauge

THE GENERAL DATA

Substantive provisions and fluctuations of an arrow of the vacuum gauge at diagnostics of malfunctions of the engine

Using the vacuum gauge, it is possible to receive the information on a condition of the engine and to define that the lining of a head of the block of cylinders is punched, the power supply system is damaged, rings are damaged, the power supply system is incorrectly adjusted, valves etc. Unfortunately are damaged, vacuum gauge indications can be interpreted incorrectly, therefore these measurements are necessary for using in a combination to other methods of check of the engine. For correct definition are important both absolute value of indications of the vacuum gauge, and speed of their change.

Connect the vacuum gauge to the inlet pipeline. Start and warm up the engine to normal working temperature.
Consider vacuum gauge indications. If the engine is in a normal state, vacuum gauge indications should be 430–560 mm Hg, and the arrow of the vacuum gauge should be at a stop.

Low constant indications of the vacuum gauge testify that the lining between the inlet pipeline and the throttle case is damaged, the vacuum hose is damaged, the moment of ignition or wrong installation of phases timing is incorrectly established.

If indications of the vacuum gauge below norm on 80 – 200 mm Hg also fluctuate, that, probably, the lining of the inlet pipeline near to an entrance aperture is damaged or the injector is faulty.

If indications constantly fall on 50 – 100 mm hg concerning stable value, that, probably, valves are damaged. In this case it is necessary to measure a compression in engine cylinders.

If indications fall, but is not regular, that, probably, gets jammed the valve or there is a failure in ignition.

If indications quickly fluctuate with amplitude about 100 mm Hg, at constant turns of idling, and from an exhaust pipe there is a smoke, probably, directing plugs of valves are damaged. If indications quickly fluctuate at increase in turns of idling, that, probably, the lining of the inlet pipeline or a lining of a head of the block of cylinders is damaged, springs of valves are weakened, valves have scorched or there is a failure in ignition.

Small fluctuations about 25 mm are hg usually connected with failures in ignition system.

If indications strongly fluctuate, that, probably, the lining of a head of the block of cylinders or the cylinder is damaged.

If the arrow slowly moves largely values, that, probably, the system of compulsory ventilation картера is littered, the lining of the inlet pipeline or a lining between the case throttle заслонки and the pipeline is damaged.

Check up, indications of the vacuum gauge after sharp and full opening throttle заслонки and its return to a starting position are how fast restored. If the engine is in a normal state, indications fall almost to zero, then increase approximately on 130 mm Hg above norm and again decrease to former values at constant turns of idling. If indications are restored slowly and pass through a maximum after closing throttle заслонки, that, probably, piston rings are damaged. If there is a long delay, that, probably, the exhaust system is littered.

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