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bmw e46 speedometer not working
The reasons for bmw e46 speedometer not working:
1. The intake pipe leaks. There are many intake manifolds or various valves in the intake system, and the leakage in the intake manifold will let the gas that should not enter, causing the concentration of mixed gas in the intake manifold to be too high or too low, which will eventually cause the engine to suffer from unstable idle speed or high and low idle speed.
2. The fuel system is blocked or faulty. As the vent hole of the fuel tank cover is blocked, the fuel tank switch, fuel filter and the fuel pipe between the fuel tank and the carburetor are partially blocked, the corresponding fuel quantity cannot be obtained when the vehicle is idling, resulting in the dilution of the mixture and unstable idling of the engine.
3. Idle speed control valve failure. The idle speed operation of the EFI engine is mostly controlled by the idle speed control valve. Once a fault occurs, the air intake will be unevenly distributed, and the engine power will vary from high to low when idling.
4. Carbon deposition. When there is too much carbon deposit in the engine, the ignition energy of the car will be reduced, and the intake efficiency will be reduced, which will eventually lead to unstable power output of the engine, idle speed jitter, and weak acceleration.
5.Cold start. When the cold car starts, the fuel injection volume of the engine is large and the idle speed is high. Especially when the car is not started for a long time or in a cold environment, it will return to normal after the engine temperature rises.
There are several main reasons for cold start jitter: carbon deposition, weak ignition, low cylinder pressure, unqualified fuel, etc.
More detailed reasons are as follows:
1: Excessive carbon deposits on the throttle, fuel injection nozzle and intake port may be one or all of them.
2: When there is too much carbon deposit in the engine, the gasoline ejected from the cold start fuel injector will be absorbed by the carbon deposit, which will lead to the lean mixture during cold start and make the start jitter.
3: Mechanical faults such as ignition coil, spark plug and fuel injection nozzle lead to cylinder shortage.
4: Low oil pressure or cylinder pressure, resulting in insufficient power, etc.
5: The fuel quality is unqualified.
6: The idle control valve is damaged or dirty.
7: Air leaks from the intake manifold.
8: The engine support arm or claw pad is damaged.
9: The oil is oxidized or of low grade, mainly due to poor low-temperature fluidity and inadequate engine cold start protection.
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