Why does the idle speed increase when turning the steering wheel while stationary in Hyundai Elantra?

[HenryAnn]

The reasons for the idle speed increasing when turning the steering wheel while stationary are as follows: Fuel pump and fuel system issues: The fuel pump and fuel system affect fuel pressure. If the pressure is too low, the actual fuel injection volume decreases under the same energizing time of the injector coil, leading to poorer spray quality and a leaner idle mixture. If the pressure is too high, excessive fuel injection results in an overly rich mixture. The fuel system pressure is related to the technical condition of the fuel pressure regulator, fuel pump, fuel pressure solenoid valve, and their circuit operation. Idle switch signal circuit issues: The engine control unit (ECU) determines whether the engine is in idle condition based on the potential level of the idle switch signal (IDL terminal). When the idle contact closes and inputs a low potential to the ECU's IDL terminal, the ECU identifies the engine as being in idle condition and activates the idle control program to regulate engine operation. Due to improper adjustment of the idle contact gap, poor contact, damage, or circuit faults, the engine ECU cannot correctly determine the idle condition, leading to idle control errors and various idle speed abnormalities. Therefore, this possibility should be prioritized and eliminated during inspection.

[StKing]

Last time I drove my friend's Elantra, I also encountered this situation where the tachometer suddenly jumped when turning the steering wheel while stationary. Actually, this is quite common - the power steering system increases engine load when applying pressure. Especially in hydraulic power steering models, the heavier you turn the steering wheel, the greater the workload of the power steering pump. To prevent stalling, the engine automatically increases fuel supply to raise the RPM. If the RPM increase isn't too large, say from 700-800 RPM to around 1000 RPM, it's basically normal. But if the RPM surges significantly or is accompanied by gurgling noises, it might indicate excessive wear of the power steering pump or a loose belt. I recommend avoiding stationary steering wheel turns as much as possible - it damages the steering gear and wastes fuel. It's better to let the car move slightly before turning the steering wheel.