What happened when the Eight-Generation Accord fell and rose?

It may be caused by engine throttle failure, idle speed control valve failure, air leakage in engine intake pipe, engine carbon deposition, charging circuit failure and other reasons. It is recommended that you contact your local 4S store for inspection and maintenance.

The reasons that cause the engine speed to fluctuate up and down during driving are as follows:

1, the charging circuit is faulty.

The failure of charging line may be caused by generator failure, battery voltage sensor failure, loose battery pile head and other reasons.

Because the generator needs to charge the battery when the vehicle is running. When the battery can't be charged or is not fully charged, the engine ECU will increase the engine speed and let the generator charge the battery, causing the tachometer to go up and down while driving.

2. The throttle valve is faulty.

The fault of the throttle may be the fault of the throttle position sensor or the fault of the throttle control motor. Throttle position sensor, as its name implies, detects the opening of throttle to control the fuel injection quantity. The function of the throttle control motor is to open the throttle at a certain angle according to the depth of the throttle.

When these two components fail, the air intake of the engine will change, causing the tachometer to fluctuate up and down when the vehicle is driving.

3. The 3.PCV valve or carbon canister solenoid valve is faulty.

PCV valve, that is, the crankcase forced ventilation valve, is used to make the combustible mixture that has escaped into the cylinder return to the intake pipe and be sucked into the cylinder for combustion; The function of the carbon canister solenoid valve is to send the gasoline vapor in the fuel tank to the intake pipe and suck it into the cylinder for combustion, thus reducing fuel consumption.

When these two valve bodies fail, the fuel entering the cylinder for combustion will deviate from the setting of ECU, causing the tachometer to fluctuate up and down while driving.

4, engine carbon deposition

Carbon deposition in engine throttle and combustion chamber will seriously affect the combustion of mixed gas. Throttle carbon deposition will affect the engine intake; However, carbon deposition in the combustion chamber will affect fuel injection and ignition, which will seriously lead to early combustion and deflagration. This will lead to unstable engine speed.