Auto Manual of VW Passat B5

2.7.3. Compression check in engine cylinders

THE GENERAL DATA

Use of a tester of measurement of pressure of compression for compression check in cylinders of the diesel engine


Check of a condition of the engine can be made by measurement of pressure of compression in engine cylinders. If this check to make regularly it is possible to learn in advance the beginning of deterioration of the engine, without waiting the moment when deterioration of the engine will be shown in a low overall performance of the engine.

Warm up the engine to working temperature. Thus the accumulator should be completely charged.

Unscrew all spark plugs.

Engines 1,6-I

Disconnect an electric socket from the ignition coil.

Five-cylinder engines

Remove the air branch pipe located between the air filter and заборником of air for what ослабьте collars and disconnect an electric socket from a measuring instrument of the expense of air. Remove an air branch pipe together with the ventilation valve картера the engine.

Five - and six-cylinder engines

Disconnect an electric socket from the block of management of ignition. The block of management of ignition is in электричес which chains between a control mean and the ignition coil.

Six-cylinder engines

Disconnect all electric sockets from fuel atomizers or take a safety lock № 28, established in a feed circuit of the fuel pump.

Include neutral transfer and tighten a manual brake.

In an aperture of a candle of the first cylinder establish компрессометр or a tester of pressure of compression.

The assistant should press an accelerator pedal against the stop and turn the engine a starter. After проворачивания a cranked shaft pressure of compression should increase by one or two turns to a maximum, and then be stabilised. Make record of the maximum received result.

Similarly check up a compression in other cylinders.

Pressure of compression in all cylinders of petrol engines should not differ more, than on 3,0 bar, and on the diesel engine – 5,0 bar. Pay attention that the compression size should increase quickly on the serviceable engine. Low pressure of compression upon the first turn of the cranked shaft, accompanied by gradual increase in pressure at the subsequent turns of a cranked shaft specifies in deterioration of piston rings.

The low size of pressure on the first turn of a cranked shaft which slightly increases further, specifies in a thinness прилегания the valves, the punched lining of a head of the block of cylinders or crack presence in a head of the block of cylinders. Deterioration of the ends of cores of valves can lead to low pressure of compression also.

If pressure in one cylinder lowered conduct following tests. Fill in through a candle aperture in the cylinder of a few engine oil and check up pressure of compression.

If pouring oil in the cylinder increases pressure of compression, it specifies that the cylinder or piston rings is worn out.

Low pressure in two next cylinders specifies in a lining burn-out between cylinders.

If pressure in one cylinder is less on 20 %, than in the others, and the engine works unstably idling, it specifies in the worn out cam of a camshaft.

If pressure of compression is too high, it specifies that the combustion chamber is covered by a thick layer of a deposit.

After this check screw in spark plugs.

Connect an electric socket to the block of management of the ignition coil. On the six-cylinder engine connect sockets to fuel atomizers or establish a safety lock in a chain of the fuel pump.

Five-cylinder engines

Establish into place an air branch pipe and fix its collars. Connect an electric socket to a measuring instrument of a stream of air.

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The prevention

After a detachment of electric sockets of system of ignition and fuel injection in an electronic control control mean the engine the message on malfunction registers. It is recommended to erase at the first possibility the information written down in memory on malfunction in a specialised workshop "Volkswagen".

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The diesel engine

Disconnect an electric socket from the valve of a stop of the engine.

Disconnect an electric socket from a flowmeter on the fuel pump.

Unscrew all candles накаливания.

Instead of candles накаливания screw in a tester of measurement of pressure of compression with a flexible transitive hose, fig. Use of a tester of measurement of pressure of compression for compression check in cylinders of the diesel engine see.

Turn a cranked shaft of the engine a starter until стабилизи руется the pressure fixed by the measuring device. Make record of the received result.

Similarly check up a compression in other cylinders.

Screw in candles накаливания, having tightened their moment of 15 Nanometers and connect to candles the tyre of giving of pressure.

Connect all earlier removed electric sockets.