The tachometer is a device, which is actively used on gasoline and diesel cars. This device is used to measure the speed of rotation (revolutions) crankshaft or generator. Most modern vehicles are equipped with a standard tachometer directly from the factory.
The need to install a tachometer on a diesel engine can arise for various reasons. It should be noted, that the connection scheme of the tachometer on the diesel is slightly different from a similar solution for gasoline engines. This feature must be taken into account when choosing a diesel tachometer, as the tachometer for petrol engines on the diesel engine will not approach.
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Where does the tachometer signal from the diesel engine come from?
Today, electronic engines are available for sale, digital and analog tachometers, the connection scheme which provides a number of features. The point is, that the place of connection of the tachometer for the diesel engine in the vast majority of cases is the generator.
To implement the connection to the generator it is necessary to have a tachometer, insulated wire and accompanying instructions for installation and operation of the car tachometer.
device connection
The principle of operation of the electronic tachometer is based on the reading of electrical pulses. Pulses are read in petrol units, which are supplied in certain quantities to the ignition coil. As for the diesel engine, then the reading is carried out with a special terminal, which is located in the generator housing.
To connect the tachometer to the diesel engine, it is desirable to carry out work on the lift or use the manhole. At the initial stage it is necessary to dismantle the protection from the generator, avoiding dirt getting inside the device. The next step is a visual inspection of the generator coil, on which there are several terminals. Tachometer contact (input wire) should be connected to that terminal, which is usually marked with the letter "W".
Also in some sources it is recommended to implement additional contact closure, coming from the oil pump. This operation is performed for this purpose, that the tachometer after installation gave the correct indications, as well as to exclude other problems. Marked, that otherwise after the output of the motor on a certain frequency of rotation of a crankshaft on the panel of devices erroneous ignition of a signal lamp is possible, indicating a critically low engine oil pressure in the engine lubrication system.
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If the terminal, marked "W", on the generator is absent at first, then you will need a separate output of a separate contact wire. Pre-prepared wires must be well insulated. The generator must be completely removed to facilitate access, as it requires partial disassembly. After disassembly, the wires will be visible (3 pieces), coming from the generator winding to the rectifier, which is also built into the device.
The prepared wire can be attached to any of these contacts, and then carry it out of the housing of the device. When finished, the generator cover is put in place, the generator itself is mounted back. Be sure to check, that in the course of assembly the wire deduced outside did not come into contact with moving elements in a design of the generator.
Next, the tachometer wire is connected to the contact output from the generator in the same way as in the presence of a terminal marked "W". The other tachometer contacts are connected according to the diagram, which is contained in the instructions for the specific device.
It is also worth considering, that direct connection of the wire to the tachometer will lead to incorrect values. Additionally, you will need a divider board, which will make the speed readings correct.