Malfunctions, repair and replacement of the VAZ 2108 generator step by step instructions

The VAZ 2108 device, like any other vehicle, involves powering electrical circuits from a battery. To ensure that the battery is always in good condition and does not let you down at the most inopportune moment, a generator is always connected to it.

The battery is especially important when the engine is ignited; while driving, when the car develops sufficient speed, the entire electrical circuit is powered by the generator.

When the question arises about connecting additional powerful electrical appliances to the car, it is very important to match their load with the permissible power of the generator. To do this, it is important to know its technical characteristics. And if the battery lack of charge indicator suddenly lights up, it’s better not to even look under the hood without understanding how the electrical charging circuit, voltage regulator and ignition work.

After reading today's article to the end, you will learn about the connection diagram and dimensions of the VAZ 2108 generator, the main reasons for failure and how to check the voltage in the circuit. If trouble happens to the generator, then don’t worry, we will clearly show you the process of removing and installing it.

VAZ 2108 generator circuit

The VAZ-2108 generator has a rather massive stator winding, since it uses a large cross-section wire. It is with its help that electricity is generated. The wire is wound evenly over the entire inner surface of the stator into recesses specially provided for this purpose in the magnetic core.

It’s worth talking about the latter separately. The middle part, the generator stator, consists of a series of thin metal plates pressed tightly together. They are often boiled on the outside to prevent separation.

1. Alternator. The 37.3701 or 94.3701 series can be installed.
2. Negative diode.
3. Additional diode.
4. Positive diode.
5. Alternator warning lamp, also known as battery discharge lamp.
6. Instrument cluster.
7. Voltmeter.
8. Relay and fuse box located in the engine compartment in the compartment between the engine and the vehicle interior.
9. Additional resistors built into the fuse mounting block.
10. Ignition relay.
11. Egnition lock.
12. Accumulator battery.
13. Capacitor.
14. Rotor winding.
15. The voltage relay is located in the engine compartment.

The principle of operation of the power supply VAZ 21099, VAZ 2109, VAZ 2108

There are 6 coils mounted inside the generator set, the material is copper, the connection is star-shaped. The stator is a stationary structure, and the rotor rotates inside the stator. Magnetic brushes are pressed into the back of the rotor axis, and the excitation winding is wound and sealed.

After the key is turned in the ignition switch, the current from the battery creates a magnetic field, passing through the graphite brushes and copper winding. Alternating current is converted to direct current.

On the front side of the IP there are two power outputs with polarity “+” and “-”. Terminals with the appropriate polarity are connected to the battery.

To turn the generator set you will need a battery. After the battery has accumulated the spent amount of energy, the generator distributes the excess to other power sources. Thus, the size of the on-board network is maintained within an acceptable range.

Technical characteristics of the VAZ 2108 generator

The following generator models are installed on VAZ 2108 cars:

1. 3701
2. 3701

Technical characteristics of the first:

• The value of the delivered current (at 6000 rpm-1 and a voltage of 13 V) – 55 A — The voltage value – 13.6 – 14.6 V
• Rotor rotation direction – right – Maximum rotor speed – 13000 rpm-1
• Engine/generator gear ratio 1/2.04

Technical characteristics of the second:

• The value of the delivered current (at 6000 rpm-1 and a voltage of 13 V) – 80 A — The voltage value – 13.2 – 14.7 V
• Rotor rotation direction: right

A normally working, serviceable generator of VAZ 2108, 2109, 21099 cars and their modifications produces a voltage in the range of 13.6 V - 14.6 V. This can be visually tracked using a voltmeter on the instrument panel, but it is better to measure the voltage with a voltmeter (multimeter, autotester

Reasons for failure of the VAZ 2108 generator

Experts believe that the main reasons for the failure of the VAZ 2108 generator are:

• voltage regulator failure;
• damage to the diode bridge (aka rectifier);
• wear of current collecting brushes;
• defects in the charging circuit wires;
• damage or operational wear of the pulley;
• wear of slip rings or commutator;
• short circuit of individual turns on the stator winding;
• bearing failure.

Every self-respecting car enthusiast should understand what causes generator malfunctions most often and how they can be dealt with. It is also necessary not to forget that timely prevention helps to avoid serious problems. Towards the end of the article, we will look at some tips that will help you learn how to test the generator yourself. But let's first learn about the internal structure of the node.

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As you know, the generator device acts as a power supply for all electrical devices of the car when the engine is running. So the failure of this unit can lead to serious consequences. In this article we will talk about how the generator of the domestic VAZ 2109 car is diagnosed and repaired and what is needed for this.

Features of work

What might a faulty unit look like, how to remove and disassemble the generator, how is it rebuilt? If the device does not charge the injector or carburetor of a VAZ 21099 or 2109, first of all, let's look at the features of its functioning, namely the power circuit.

Generator power circuit

Node power circuit

So, what does the scheme include:

1. The VAZ 2109 generator itself.
2. Negative diode.
3. Additional element.
4. Positive diode.
5. The warning light also informs the driver that the battery is low.
6. Vehicle dashboard.
7. Voltmeter.
8. The fuse box is installed in the engine compartment under the windshield opposite the driver's seat.
9. Resistor elements installed in the same block.
10. Ignition relay "nine".
11. The castle itself.
12. Battery
13. Capacitor device.
14. Winding.
15. Generator voltage regulator relay installed in the engine compartment.

It should be noted that the connection diagram for the VAZ 2109 generator is relevant for all cars with front-wheel drive of the eighth line - both 2108 and 21099 (the author of the video is Semyon Pedan).

Checking for serviceability

Repair of the VAZ 2109 or VAZ 21099 generator is carried out in case of failures in the operation of the unit. There are several ways to determine generator malfunctions. The most optimal of these is diagnostics using a multimeter, but you will also need an assistant to carry it out. We will tell you further about how to check the generator on a VAZ 21099 or 2109 using a tester.

So, to determine generator faults with a multimeter, follow these steps:

1. First of all, it is necessary to diagnose the VAZ voltage regulator. As practice shows, if the generator on a VAZ 2109 or VAZ 21099 does not work correctly, the problem may lie in the functionality of the three-level voltage regulator. This is especially facilitated by overvoltage in the electrical circuit. To check, you need to set the voltage measurement mode on the tester. So, start the engine and measure the voltage at the battery terminals or at the terminals of the generator unit itself. If everything is normal, then this parameter will fluctuate around 14-14.2 volts. Then press the gas and check the parameter again - it should increase, but no more than 0.5 volts. If the indicators on a VAZ 2109 carburetor or VAZ 21099 injector are different, this indicates that the element is not functioning correctly. Most likely, the VAZ 2109 voltage relay will have to be replaced.
2. Next, the diode bridge of the generator is diagnosed. The bridge itself consists of six elements, three of which are considered positive and the remaining three are considered negative. Some diodes have mass at the anode, and the other part at the cathode. To check the diode bridge of the VAZ generator, the tester is switched to sound mode, that is, when the probe outputs are shorted, you can hear a characteristic sound. You are required to test each diode in different directions, and the sound should be heard in only one of them. If during testing the sound is heard in both directions, this indicates that the diode is broken. The best option would be to replace the diode bridge.
3. Before disassembling the unit and repairing it, check the functionality of the stator; it is a steel cylinder, inside of which the winding of the mechanism is located. For diagnostics, you need to disconnect the stator leads from the diode bridge. First, inspect the element visually - there should be no signs of damage or burning. The multimeter is set to resistance measurement mode. First, measure the resistance parameter between the winding terminal and the housing (any terminal can be used). The obtained indicators should be high and tend to infinity. If the readings are 50 kOhm, this indicates the need to replace the generator.
4. Using a multimeter, you can also check the performance of the rotor - it is a steel rod with a wound winding. At one end of the rod there are rings through which the brushes of the VAZ generator pass. You need to dismantle the rotor and visually inspect the condition of the generator winding and bearing. The integrity of the winding can be checked using a multimeter, after which the resistance parameter between the rings is measured. The results obtained should be no more than a few ohms. Replacing the VAZ 2109 generator brushes is required if they are worn out.

Node diagnostics with a tester

Possible faults

Before removing the generator and repairing the disassembled device, we will consider the main malfunctions characteristic of this unit:

1. When the ignition is turned on, the mechanism light does not light up. As a rule, this problem is associated with a broken ignition switch, possible breaks in the wire, or a broken fuse. First of all, it is necessary to diagnose the fuses and wiring; the electrical circuit is checked using a tester.
2. The unit light does not light up, and the battery is greatly discharged, but the control devices function normally. Usually the cause of the breakdown in this case lies in the performance of the generator. We are talking about a possible short circuit of the diodes, poor contact of the excitation winding connection, failure of the relay or inoperability of the brush holders. In addition, in some cases, the problem may lie in a break in the wiring that goes from the generator unit to the control panel. Perhaps the reason is simply poor contact of the light bulb itself or its failure. In order for the unit to supply current and operate normally, all its elements must be operational. If the problem is with the brushes, then they need to be replaced with similar ones of the same size.
3. The unit light works when the engine is on, and the battery can be recharged. First of all, pay attention to the performance of the regulator.
4. When the engine is running, the light on the dashboard lights up very brightly or only at 50%. In this case, it is necessary to diagnose the VAZ alternator belt - perhaps it is worn out or simply weakened. Replacing the strap or tightening it can solve the problem. In some cases, the cause of the malfunction lies in a short-circuit of the stator winding to ground or an open circuit. The problem may also be the inoperability of the diodes or the rotor outputs being unsoldered from the slip rings. You can try to solve the problem by soldering the leads.
5. If the unit is very noisy, first you should check the bearing device. In addition, the appearance of noise may be caused by a short circuit of the stator winding to ground or a short circuit of one of the diode components (video author - Vyacheslav Lyakhov).

DIY replacement and removal

So, how to disassemble a VAZ generator:

1. First, disconnect the battery by removing the terminals from it, this way you can turn off the power to the on-board network.
2. Remove the cap from the terminal and unscrew the corresponding nut, after which you can remove the wiring from the stud.
3. Disconnect the wiring block that goes to the node connector.
4. Now you need to slightly loosen the tightening of the assembly to the adjustment bar. Having done this, you can lift the assembly up until it rests against the head of the BC. The generator pulley can then be freed from the belt.
5. After these steps, you can completely unscrew the screw securing the bar to the BC. Then crawl under the car and remove the screws that secure the bracket to the engine. The unit can be dismantled by removing it from the engine compartment. The failed elements are disassembled and replaced with new ones, after which the generator is reassembled.

How to check the voltage of the VAZ 2108 generator

In order to check the performance of the VAZ 2108 generator, you need to perform the following steps:

1. Using a voltmeter, diagnose the voltage at the battery terminals. When the engine is running and the generator unit is operating normally, this parameter should be around 13.8-14.5 volts.
2. Try placing your palm on the unit body with the engine running, you need to feel the vibration. If there is vibration, you will notice it immediately. Moreover, it may be due to wear of bearing parts.
3. It is also necessary to diagnose the tension of the device strap, while the motor must be turned off. Press the strap with your finger - the deflection should be no more than 1.5 cm

Common faults

The electric generator is located under the hood of the car and operates from a belt drive. The most common causes of generator breakdowns are as follows:

• The tension is loose or the alternator belt is stretched
• Charging relay faulty
• Generator brushes worn out
• The diode bridge has failed
• The bearing (or both bearings) of the rotor shaft is jammed

Troubleshooting check

Signs of malfunctions and their identification:

• Extraneous noises are heard that are clearly audible during operation
  - this is a likely sign of wear on the shaft bearings
• Low voltage received at the “output” from the generator
  means worn brushes or weakened belt tension
• An increase or decrease in voltage received at the “output”
  may be caused by a malfunction of the diode bridge

Troubleshooting via the instrument panel warning lamp

What does a lit red light on the dashboard with a picture of a battery mean:

• In any case, this is a signal that the voltage at the output of the unit is lower than the battery voltage, or vice versa, the battery voltage is lower than the voltage supplied from the generator
• When the light goes out as the engine speed increases, the problem is most likely related to the generator
• If it starts to shine brighter, it’s time to change the battery

To perform initial diagnostics of faults, you just need to do the following procedures:

• Check the voltage at the battery terminals (contacts) using a voltmeter. With the engine running and the alternator working, the voltage on the battery should be between 13.8 - 14.5 volts
• With the engine running, touch the body of the device with your palm to detect vibration. When the wear of the shaft bearings is increased, their vibration transmitted through the generator housing is more than noticeable; it is very difficult to confuse it with something else
• Check the belt tension: with the engine stopped, you need to press the belt with your fingers - its deflection should not exceed 1 - 1.5 centimeters

Interchangeability of the VAZ 2108 and VAZ 2106 generator

The idea of ​​replacing a generator on a classic is as old as the history of the car itself, because everyone who installs more bells and whistles on their own car than a weak Chinese radio, the native 42A G-221 is no longer enough for everyone.

True, even those who neglect the hassle of installing a more powerful generator are annoyed by the weak low beam at idle and poor battery charge. Once, an acquaintance fitted me with a 55A generator on a ball and the idea arose about telling you how to install it in our classic.

Having scoured the Internet to find at least something about installing and connecting it to a car, I didn’t find anything useful, a lot of comments like “Plug it in and forget it” or long discussions of professional electricians, but they spoke in a language that would suit a simple Russian to a person, it’s like a Chinese song, nothing is clear.

In this regard, it was decided to write an understandable article for ordinary people in order to help them do this simple procedure of replacing the generator themselves, without any problems and special skills in working with electricity, but with their hands. It is important to know: There are many alternatives to a standard generator, since with the appropriate skills, means and desire it is possible to install any generator. In the provided article I examine only “economical” VAZ generators from other models, because:

• They are cheaper.
• They are more common.
• They are easier to change - you don’t need to find or make any special fasteners and completely change the electrical system.

How to remove the generator on a VAZ 2108 yourself step by step instructions

In order to remove the VAZ 2108 generator with your own hands, you must perform the following procedure:

1. In order to easily remove the VAZ 2108 generator, it is necessary to remove the engine protection.

2. During the dismantling process, the VAZ generator must be removed together with the bracket, since its fastening bolt will be impossible to pull out due to the position of the body side member.

3. Now disconnect all electrical terminals from the generator

4. Then you need to loosen the adjusting nut and the generator mounting nut from below.

5. Move the generator forward and remove the loose belt

6. Unscrew the bolt and remove the adjusting bar

7. We find it at the bottom of the engine compartment (shown in the photo) and unscrew the two bolts securing the bracket.
8. Then, carefully pushing down, remove the VAZ 2108 generator

9. After repairing or purchasing a new generator, we install it in the reverse order, taking into account the fact that the long bolt securing the bracket should be closer to the generator drive.
10. After completing the installation of the VAZ 2108 generator, tension the drive belt

Replacement and removal of the electric generator

The generator on a VAZ car is removed either for complete replacement in case of failure or to carry out repair work to replace faulty parts. To perform dismantling, prepare a standard set of tools; it is advisable to drive the car into the inspection hole.

1. Disconnect the battery.
2. Remove the protective rubber cap from terminal “30” and unscrew the nut and remove it from the wire stud.
3. Disconnect the block with wires from the generator connector.
4. We loosen the tightening of the generator to the adjusting bar, then lift it all the way up to the cylinder block and remove the belt from the pulleys.
5. Completely unscrew the bolt securing the adjusting bar to the cylinder block, then from the bottom of the car unscrew the 2 bolts securing the lower bracket to the block and remove the generator, pulling it out of the engine compartment.

It may seem wild to some, but very often you come across owners of VAZ 2109-2108 who, at the first malfunction of the generator, prefer not to repair it, but simply replace the device with a new one. There are even those who don’t bother to check the wear of the brushes, but immediately run for a new generator. In fact, you can perform a repair, that is, replace a obviously faulty part with a new one and that’s it, the device will work for another hundred years!

In order to disassemble the generator on a VAZ 2109-2108, we will need the following tool:

• open-end or socket wrench 17
• 10 and 7 mm head
• ratchet handle
• Phillips and flat screwdriver

How to install and connect a VAZ 2108 generator - step-by-step instructions

Installation of a new generator is carried out in the reverse order. Take a close look at the condition of the bottom bolt. If there is damage to the threads, it is better to replace it.

It will be easier for you to repair the generator later. When installing, pay special attention to belt tension. If it is not tensioned enough, your battery will not charge well. But if you tighten the belt too much, the bearing in the front cover will be destroyed. As a result, you will get an unpleasant whistle when the engine is running. And the reason for this is the appearance of play in the bearing.

The installation of the generator on the VAZ 2108 must be carried out in such a way that even the slightest distortion does not occur.