VAZ 2105: tachometer for a car and its main functions

A tachometer is considered a useful device for a car, since it records the revolutions made by the crankshaft. Many car owners often install it on carburetor VAZ-2105 cars, because these elements are not provided by the manufacturer.

They are especially necessary for novice drivers who cannot track the operation of the engine only by its sounds.

And in order to prevent serious breakdowns and malfunctions, you should install a tachometer on the VAZ model 2105. But first you should consider the features of this device.

Installation Features

As noted above, owners of the VAZ-2105 are recommended to replace the instrument panel with the one that was mounted on the 2107. If you do not want to do this, then a remote option is selected.
It is fixed either on the bracket supplied in the kit or in a special frame-pocket - those are sold separately. For the 2105 model, the tachometer designed for the VAZ-2106 is perfect. To connect it, you will have to cut off the connector with contacts, since there is nowhere to plug it into the “five”. Further switching is done by extending the wires and connecting them with terminal strips (sold in electrical goods stores). It is important to consider the following:

• one cable (marked with brown insulation) is attached to the plus of the ignition coil;
• black and white goes to mass;
• orange (sometimes yellow) connects to battery positive.

The electronic tachometer is installed in the same way.

Installation on a car with a carburetor

Before connecting the tachometer, it must be installed in the location chosen for it. This way you can immediately see what length of wire you will need. Then the negative cable is connected to ground. It, as previously reported, is black and white or quite charcoal in color.

Connect the brown or reddish wire to the ignition switch contact. Look at the diagram where the positive comes from the battery. If it is not there, then find it using a tester. This is done like this:

• Set the multimeter to 20 V;
• Place the dark probe on ground;
• Touch all the contacts alternately with the red one - the one you are looking for will have 12 volts.

The last posting is used to obtain data on the number of crankshaft revolutions 2105. Its color is not defined; each manufacturer uses its own. This cable in the contact ignition system goes to the distributor breaker. Otherwise, it is connected directly to the voltage switch. If the tachometer has its own backlight, then it is additionally connected to the car’s side lights circuit.

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Design, principle of operation, repair and replacement of the tachometer of the VAZ 2106
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Why

Step-by-step connection of a tachometer on a VAZ 2109: diagram, video

The tachometer is not one of the “vital” devices of the “seven”, but its malfunction causes certain inconvenience. In addition, the situation when the VAZ 2107 tachometer jumps is a sign of problems in the ignition system or fuel supply to the engine. Therefore, at the first sign of a malfunctioning tachometer, you need to understand the causes of the breakdown and eliminate them immediately.

The connection diagram for the tachometer on a VAZ 2107 with a carburetor engine is slightly different from that used on models with an injector. But in general, the causes of the malfunction and the methods for eliminating them are similar.

Connecting a tachometer on carburetor and injection models

The connection diagram for the VAZ 2107 tachometer on an injection machine differs in that in this case the device reads data on engine speed not from the ignition coil, but from the engine ECU. In general, the connection procedure and operating principle are no different. The device has three terminals, two of which are connected to the “plus” from the ignition switch and “ground”, and to the third - a wire from the ignition coil or engine ECU.

Where to start troubleshooting

To troubleshoot, you will need a multimeter or “tester”. If the tachometer on a VAZ 2107 (injector) does not work, you should first look to see if the “Check Engine” warning light is on. If this is the case, then you can find out the cause of the breakdown by reading the error code from the controller. If the lamp does not light, you can skip this point.

Next, on the injection and carburetor models, you should check the condition of the electrical wiring going to the tachometer. The insulation of the wires must not be damaged, the tachometer must have good contact with ground, power and terminal “K” of the ignition coil or the engine ECU output. In addition, there may be a break or poor contact inside the device itself. In this case, it will have to be replaced.

If everything is in order with the wires and contacts, the problem is in the Hall sensor (on the injection “seven”), the ignition or fuel supply system.

Checking the ignition system

The VAZ 2107 tachometer circuit is the same for all models, the only difference is where it gets the data from. In the carburetor “seven”, information about engine speed is read from the ignition coil: every two spark discharges on the spark plugs is one engine revolution.

The tachometer may malfunction if the insulation of high-voltage wires is broken or the ignition coil is faulty. In this case, interruptions in engine operation and “floating” speed are also possible. In addition to the wires and coil, it is necessary to check the condition and adjustment of the breaker contact and the capacitance of the capacitor on it.

Faulty wires and, as a result, unstable engine operation, cause the tachometer to “jump” on injection VAZ models.

Hall Sensor

The tachometer on the VAZ 2107 (injector) reads information about engine speed from the computer. The latter, in turn, receives data from the Hall sensor. Poor contact at the sensor terminals or its malfunction leads to interruptions in engine operation and fluctuations in the tachometer needle. If the contacts can be cleaned, the sensor itself cannot be repaired. It is designed in such a way that the possibility of its repair is excluded. The faulty sensor must be replaced with a new one.

Fuel system malfunction

The cause of interruptions in engine operation and jumps in the tachometer needle can be either low-quality fuel or problems in the injection system. On carburetor models, disassemble the carburetor and clean the jets.

Most often, a “jumping” tachometer is the result of a clogged idle jet. The VAZ 2107 tachometer (injector) can “jump” if there are problems in the injection system. In this case, it is necessary to flush the injectors.

To check and clean the injection system, you need a special stand and equipment. It is better to entrust such work to service station specialists.

Malfunction of the gas distribution mechanism

When the tachometer needle begins to “jump” at high speeds, the problem may be associated with a malfunctioning gas distribution mechanism. In this case, it is necessary to check the tension of the timing belt connecting the crankshaft to the camshaft.

In addition, the speed may “float” due to a malfunction of the engine itself. Here it is worth checking the compression in the cylinders or contacting an auto mechanic.

If you delay diagnosis and repair, serious damage to the piston system may occur, which will require expensive complex repairs.

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Tachometer malfunctions

Despite the fact that the TX-193 tachometer is considered quite reliable, it also has malfunctions. Their signs are:

• lack of response of the needle to changes in engine speed;
• chaotic movement of the arrow up and down, regardless of the engine operating mode;
• obvious underestimation or overestimation of readings.

What kind of breakdowns do the listed signs indicate?

The arrow does not respond to measuring the number of revolutions

Usually, the lack of response from the arrow is due to a broken contact in the connectors of the main wires of its connection, or damage to the wiring of the circuit. The first step is:

1. Inspect the fastening of the conductor in brown insulation to terminal “K” on the ignition coil. If you detect poor contact, traces of oxidation, burning of a wire or terminal, fix the problem by cleaning the problem areas, treating them with anti-corrosion liquid, and tightening the fastening nut.
2. Check the reliability of the connection of the black and white wire to the vehicle ground. If contact is broken, clean the wire and the surface to which it is attached.
3. Using a tester, determine whether voltage is supplied to the red wire when the ignition is on. If there is no voltage, check the serviceability of fuse F-9, which is responsible for the integrity of the instrument panel circuit, as well as the condition of the ignition switch contacts.
4. Disassemble the instrument panel and check the connections of the contacts in the tachometer wiring harness block. “Ring” all the wires going to the device with a tester.

Video: tachometer needle does not respond to engine speed

The tachometer needle jumps chaotically

Jumps in the TX-193 needle in most cases are also a symptom of malfunctions associated with its electrical circuit. The reasons for this behavior of the device may be:

• lack of good contact at the negative terminal of the battery;
• oxidation or burning of the brown wire on the ignition coil;
• burning or wear of the contacts of the ignition distributor cap or slider;
• wear of the distributor shaft bearing;
• shorting the red wire powering the device to vehicle ground;
• malfunction of the crankshaft position sensor (for injection engines).

A similar problem is solved by stripping the contacts, replacing the ignition distributor cap, slider, support bearing, restoring the integrity of the insulation of the device’s supply wire, and replacing the crankshaft sensor.

Video: tachometer needle jumps

The tachometer underestimates or overestimates the readings

If the device is outright lying, then the problem most likely lies in the ignition system. In other words, it shows correctly, but the number of pulses created by the chopper per revolution of the distributor shaft is more or less than four. If the tachometer readings are incorrect, there is usually a deterioration in engine performance. In this case, the speed may fluctuate, misfires periodically appear, which is accompanied by engine vibration and white or bluish exhaust.

In this case, the fault should be looked for in the breaker, or rather, in its contact group or capacitor. To fix this problem you need to:

1. Disassemble the ignition distributor.
2. Check the condition of the breaker contacts.
3. Clean contacts.
4. Adjust the gaps between the contacts.
5. Check the serviceability of the capacitor installed in the breaker.
6. Check the serviceability of the crankshaft position sensor. In case of malfunction, replace it.

However, the reason may be in the tachometer itself. Malfunctions occur related to the parts of the electronic board, as well as to the milliammeter winding. You can't do without knowledge of electronics here.

Incompatibility of the TX-193 tachometer with a contactless ignition system

Older models of TX-193 devices are designed exclusively for contact ignition systems. All owners of “sixes” who independently converted their cars to a contactless system subsequently encountered problems with the tachometer. It's all about the different forms of electrical impulses arriving at the device from the breaker (in a contact system) and the switch (in a contactless system). The simplest way to solve this problem is to install a capacitor in the cut of the same brown wire coming from the breaker. But here it is necessary to experimentally select the desired container. Otherwise, the tachometer will lie. So, if you have no desire to engage in such experiments, just buy a device for a contactless ignition system.

Possible damage to the tachometer and methods of elimination

VAZ 2114 tachometer sensor where is it located

If we talk about malfunctions, if the tachometer fails to work, the process of finding them may vary depending on the type of motor.

1. Carburetor. On such a motor, 3 wires are connected to the device, 2 are power, the 3rd is connected to the coil. To determine the cause of damage to the measuring device, it is necessary to approach the control panel (rear part) and disconnect the terminals included in the device. Next, using 3 other working wires, the device must be directly connected to the battery and coil. When starting the unit, the device should begin to function if the cause is the circuit. If this does not happen, you need to look for a problem in the ignition or the device itself.
2. Injection engine. In this situation, the tachometer connection diagram is different. There are 4 wires used here, 2 for power, 1 is directed to the electrical control unit, another 1 is directed to the crankshaft sensor. A fairly acceptable option would be to perform computer diagnostics. In addition, it’s time to try checking the position on the contact connectors or install a new DPKV.

Comments

good idea

It turned out so well, I didn’t have enough tach in my five. But in the beard, where the instruments stand, put some kind of solid plate so that the plugs are not visible. And so-zer good!

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good idea

I did the same for myself, only I cut out a solid plate into my beard, and now no plugs or other crap are visible there