tachometer reading too high

• 2021-12-30

The design of the tachometer of each manufacturer is roughly the same. The reading of the tachometer is generally the indicator of the tachometer multiplied by 1000 or 100, that is, the engine speed per minute. For example, the engine is generally 700-1100r / min at idle speed, that is, 700-1100 rpm. Generally, the tachometer will be divided into several areas. The white scale area is the range of safe speed, the red scale part is the range of dangerous speed, and some models will be divided into green areas, which is the most economical use range of the engine.

The reasons for high vehicle speed are poor oil quality, throttle assembly failure, fuel pump and oil circuit system failure, air conditioning clutch slip or damage, etc.

Poor oil quality

If the vehicle uses inferior fuel, the fuel in the engine cylinder will not fully burn with the air, resulting in abnormal engine and high speed of the vehicle.

Throttle assembly failure

When the opening of the throttle valve is large, the speed will become higher. The gasoline engine throttle does not control the fuel injection quantity, it controls the throttle opening. That is, the opening is small, and there is less mixed gas entering the cylinder, so the power emitted by the engine is small, and vice versa. The more mixed gas entering the cylinder, the greater the force generated by combustion. In this way, the greater the force to push the piston and the faster the piston moves, which makes the car rotate at a high speed.

Fuel pump and oil circuit system failure

Leakage or blockage of the fuel injection nozzle makes it impossible to inject fuel according to the instructions of the electronic control unit, resulting in too rich or too thin mixture, resulting in poor operation of individual cylinders and unstable idle speed.

Air conditioning clutch slips or is damaged

Manual transmission, double clutch transmission and semi-automatic transmission all use friction plate clutch to transmit the power of the engine. If the pressing torque is not enough or the friction plate is seriously worn, slip will occur, resulting in high speed of the car.

You can check whether there is much carbon deposit on the throttle. Generally, too much carbon deposit on the throttle will lead to unstable idle speed and high vehicle speed. Also, check whether the gap of the spark plug is large!