What Causes Engine Stall on Downhill?

[MacJake]

Engine stall occurs when the vehicle's running resistance significantly exceeds the engine's output power. Normally, vehicles—especially fuel-injected ones—do not stall during downhill driving. Downhill stalling may happen on steep slopes when using low gears (or reverse gear), where the vehicle's momentum surpasses the engine's current output power due to power reversal. It is recommended to use brakes and engine braking appropriately during downhill driving. Below are additional details: 1. Downhill with Engine Off: Turning off the engine while going downhill removes traction resistance and cuts power to steering assistance, making brake failure extremely dangerous. Never coast downhill with the engine off or in neutral, as this can lead to loss of vehicle control and accelerated brake pad wear. 2. Forced Downshifting: Do not turn off the engine to save fuel on downhill sections. If the engine stalls abnormally, manual transmission vehicles can employ forced downshifting or gradually apply the handbrake using a repeated pull-release method to slow down and stop the vehicle.