how to fix a broken tachometer

• 2021-12-29

Check whether the tachometer wire is disconnected. One side is on the engine and the other side is on the tachometer. Clean the throttle valve of the fuel injection nozzle, replace the spark plug, and then check whether the three-way catalytic package can exhaust smoothly and whether there is any sign of blockage after adjusting the ignition.

Check whether the connector of the sensor is loose and whether the sensor installation is loose. After unplugging the connector of the engine speed sensor, use the resistance gear of the multimeter to measure the resistance of the sensor coil, which is consistent with the specified value. If the resistance is too large or too small, replace the sensor.

Start the engine and measure the voltage of the sensor signal output terminal with the AC voltage gear of the multimeter. The voltage should be about 0.5V when the engine is idling, and the output voltage of the sensor increases with the increase of engine speed. Otherwise, the sensor is defective and needs to be replaced.

Check the signal circuit of the engine tachometer. Check whether the line connection at the terminal of the ignition coil is loose and whether the wire is damaged. If the connection line is normal, disassemble the instrument panel and check whether the connection of relevant lines inside the instrument panel is bad. If the line connection is good, repair or replace the engine tachometer core.

And check the needle if it is stuck. If yes , can change a new needle.

Check whether the flexible shaft is disconnected, and then check whether the mileage increases when starting. If the tachometer doesn't move. There's no need to repair it. Let's get a new one. As long as the car starts, the gears in the tachometer are rotating. They are worn out over time. The gears in the tachometer are plastic and new ones don't cost much. The tachometer is generally set in the instrument panel and placed symmetrically with the speedometer. The tachometer works according to the magnetic principle. It receives the pulse signal generated when the primary current in the ignition coil is interrupted and converts this signal into a displayed speed value. The faster the engine speed, the more pulses generated by the ignition coil, and the greater the speed value displayed on the table. Cars are generally electronic tachometers, including pointer type and liquid crystal digital display type. There is a digital integrated circuit in the meter. It drives the pointer to move or digital display after calculating the voltage pulse transmitted from the ignition coil. In addition, there is a tachometer that takes out the pulse signal from the generator and sends it to the tachometer circuit for interpretation to display the speed value. However, due to factors such as generator belt slip, the value is not accurate.

If the tachometer is not work, need to change.