Audi А4
+ Running gear
+ Regular servicing
+ Engines
+ Turbo-supercharging
+ Exhaust system
+ Cooling system
+ Fuel tank and the fuel pump
+ The air filter and channels всасывания
- Injection system
+ System of injection Motronic
- System of injection MPI and MPFI
Additional functions
Knots of system of injection
Functioning
Adjustment by means of a ljambda-probe
Infringements in work and self-diagnostics
The self-help
The visual control
Check of knots
Dismantle of separate details
Cable throttle заслонки
Inlet collector
Idling adjustment
Check of the fulfilled gases
The help at malfunctions
+ Coupling
+ Transmission and the main transfer
+ Suspension bracket of wheels and steering
+ Brakes
+ Wheels and tyres
+ The electrotechnical equipment
+ Ignition system
+ Illumination
+ The alarm equipment
+ Tools and devices
+ Heating and ventilation
+ Body details
+ Salon
Search of malfunctions
Technical characteristics
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Check of knots
In following sections checks of elements of system of injection, possible with use of amateur means are described.
Injection valves
If there is a suspicion that one of injection valves does not function, you can easily find out it by means of the light-emitting diode indicator of pressure and an exact ohmmeter.
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- Dismantle an engine cover.
- Disconnect sockets of valves of injection.
- In the beginning pressure check: connect the light-emitting diode indicator of pressure (not a control lamp) to socket contacts. Start the engine: the light-emitting diode in the pressure indicator should flash, if is not present, pressure does not move or the block of management connecting weight, is faulty. This check cannot be spent the measuring device.
- Resistance check: disconnect sockets of valves of injection, connect an ohmmeter to both contacts of the valve: if the engine cold the device will show 13,5–17 Ohm.
- If the size is not tolerant, replace the valve (if measurement has been spent precisely).
- Tightness check: dismantle a distributive tube of fuel together with injection valves.
- Sockets of valves of injection are disconnected, топливопроводы remain connected.
- Let your assistant some times will turn the engine a starter that has earned the fuel pump and there was a pressure of fuel.
- Observe injection valves: each of them should let out a maximum of 1-2 drops of fuel in a minute. Otherwise replace the corresponding valve.
- Irrespective of it it is possible to check up a stream of injection and quantity of fuel injected by the valve if it is necessary because of infringements in engine work.
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Potentiometer throttle заслонки
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- Disconnect a socket of a potentiometer throttle заслонки.
- By exact ohmmeter measure resistance between potentiometer contacts.
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Position throttle заслонки
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Measurement between contacts
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Nominal size (clod)
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| Has no value |
1 and 2
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1,5–2,6
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| Idling |
2 and 3
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0,75–1,3
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| Full gas |
2 and 3
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As much as possible 3,6
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Having disconnected a socket (1), it is possible to measure pressure giving on valves of injection (2) by means of the light-emitting diode indicator of pressure. When the engine is turned by a starter, light-emitting diodes in the pressure indicator should flash. If is not present, pressure does not move. |
Measuring instrument of weight of air
Only MPI
On the right: in a photo (1) engines with working volume 2,8 l and a three-polar socket (2) are shown a measuring instrument of weight of air.
At the left: the scheme of an arrangement of contacts of a three-polar socket is used for check of a measuring instrument of weight of air.
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- Measurements are made at throttle заслонке in position "idling" and full gas at the idle engine.
- Following nominal sizes should be received:
- Shift back a rubber tip on a socket of a measuring instrument of weight of air, the socket remains connected.
- Connect the exact voltmeter to socket contacts behind how it is described more low:
- Measurement 1: connect measuring wires to contacts 2 and 3.
- Include ignition.
- The voltmeter should show 12–14 V.Esli is not present, defect in pressure giving.
- Check up a safety lock 32 if it is necessary, check up a wire from a safety lock 32 to contact 3 sockets of a measuring instrument of weight of air.
- Or check up connection from weight of the engine to contact 2.
- Measurement 2: connect measuring wires to contacts 1 and 2.
- Include ignition.
- The voltmeter should show 0,3–1,1 Century
- Start the engine (the wire remains connected). Switch off all consumers, the radiator fan should not work
- l Consistently force to fluctuate engine turns between idling and 4000 rpm.
- The voltmeter should show (depending on number of turns) from 1,5 to maximum 3,4 V.Esli are not present, the measuring instrument of weight of air is faulty. Replace it.
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The valve of stabilisation of idling
Only MPI
With working volume 2,8 l the valve of stabilisation of idling is in the engine on the right on a branch pipe throttle заслонки.
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- Disconnect a socket of the valve of stabilisation of idling and connect an exact ohmmeter to both contacts of a socket of the valve.
- The measuring device should show 7–11 Ohm, otherwise the valve is faulty.
- Deeper check of working capacity: dismantle the valve of stabilisation of idling; the socket remains connected.
- Rotor in air pass of the valve put in position "openly" or "is closed" (do not use for this purpose the metal tool).
- Include ignition and observe a rotor: he should fluctuate approximately on the average position.
- Check up ease of a course of a rotor: it should move for the account толчкообразного movements of the dismantled valve.
- Besides, on it there should not be jags or attritions.
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The valve of stabilisation of idling
Only MPFI
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In a photo the valve of stabilisation of idling (marksman) in the engine with working volume 2,6 l is shown. |
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The valve of stabilisation of idling (1) with working volume 2,8 l is in the six-cylinder engine near to a regulator of pressure of fuel (2) as you can see in this photo. |
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Attention! The valve of stabilisation of idling of the engine with working volume cannot be dismantled 2,6 l in a house workshop as right after installation so-called basic adjustment of system of injection should be spent that it is possible to make only by means of the device for reading of malfunctions V.A.G 1551 in workshop Audi.
If the socket on the valve of stabilisation of idling is disconnected within 1/2 hours after last deenergizing of the engine malfunction defect of the valve of stabilisation of idling will be kept in memory of the computer (that, maybe, has not been made before). |
In this valve the winding is checked only:
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- Disconnect a socket on the valve of stabilisation of idling.
- By exact ohmmeter measure resistance between contacts of a socket 1 and 4, and also 2 and 3 valves.
- If in working order the device should show 45–60 Ohm, otherwise the valve it is necessary to consider the valve defective.
- By own strength it is impossible to spend other checks.
- If the workshop replaces the valve at once spends the mentioned basic adjustment.
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The gauge of temperature of a cooling liquid of system of ignition/injection
At the left: behind on the engine screwed up in a tube of giving of a cooling liquid there is a combined gauge of temperature of a cooling liquid (1) systems of ignition/injection and the temperature indicator. Here the socket (2) is disconnected for gauge check. Contacts of a socket concern injection system 1 and 3.
On the right: the diagramme shows, at what temperature what size of resistance this gauge should show.
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Attention! If the socket on the gauge of temperature of a cooling liquid in the engine with working volume 2,6 l is disconnected within 1/2 hours after last deenergizing of the engine malfunction defect of the gauge of temperature of a cooling liquid will be kept in memory of the computer (that, maybe, has not been made before). |
General provisions: the reason can be in the gauge of temperature of a cooling liquid if in certain ranges of temperature there are lacks of engine work. Check:
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- Disconnect a socket on the gauge of temperature of a cooling liquid.
- Measure by an ohmmeter resistance between contacts of a socket 1 and 3 gauges.
- The measured resistance is compared depending on temperature of the engine to the diagramme of nominal size below. If the size is on considerable distance out of curves, replace the temperature gauge.
- In summary here it is necessary to name two more rough sizes of resistance: at temperature of a cooling liquid 20 С the ohmmeter should show nearby 2,5 clod, at 80 С – nearby 330 Ohm.
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The gauge of temperature of soaked up air
Only MPFI
On the right: the gauge of temperature of soaked up air (3) is only in the engine with working volume 2,6 l. It is on the right behind on the engine near to the valve of stabilisation of idling (1) and a regulator of pressure of fuel (2).
At the left: on this diagramme the size of resistance of the gauge depending on temperature of soaked up air is shown.
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Attention! If the socket on the gauge of temperature of soaked up air is disconnected within 1,5 hours after last deenergizing of the engine malfunction defect of the gauge of temperature of soaked up air will be kept in memory of the computer (that, maybe, has not been made before). |
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- Disconnect a socket of the gauge of temperature of soaked up air.
- Measure by an exact ohmmeter resistance between two contacts of a socket of the gauge.
- Compare the measured resistance depending on temperature of the engine to nominal size in the diagramme below. If the size is on considerable distance out of curves, replace the temperature gauge.
- In summary here the rough size of resistance is resulted: at 20 С (a room temperature, the engine cold) the device should show nearby 6,3 clod.
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