What Causes a Car Not to Start on Rainy Days?
2 Answers
If a car fails to start on rainy days, it is likely due to rust or leakage in the battery, or the engine spark plugs getting damp. The best solution is to move the car to a sunny spot when the weather is clear to evaporate any moisture in the corners. Here are some additional details: 1. Low Battery Voltage: In cold temperatures, the electrolyte viscosity in the battery increases, reducing its permeability and increasing resistance, which lowers the output power. This makes it difficult for the starter to crank the engine to the minimum starting speed, affecting engine ignition. Additionally, the weak spark from the spark plugs due to low battery voltage, combined with the increased resistance between electrodes caused by dense air-fuel mixture, makes it hard to ignite the mixture, further complicating engine startup. 2. Short Circuits or Clogged Fuel Lines: Since most of the vehicle's wiring and fuel lines are concentrated in the engine compartment, driving through water can cause these components to get wet. Over time, this may lead to short circuits in the wiring or clogged fuel lines, directly resulting in the car not starting. For vehicles that have been submerged in water, there may be even more issues. Even after drying the engine compartment, attempting to start the engine still carries some risk.
I remember one rainy day when my car wouldn't start either. After struggling for a long time, I finally realized it was because the ignition system got wet—rainwater had seeped into the wire connectors, causing a short circuit or oxidation. Check under the hood; wire connectors and battery terminals are prone to rust and corrosion, especially in older cars. If the spark plugs or ignition coils get wet, they can also prevent the car from starting. The solution is to wipe the connectors with a dry cloth, spray some rust inhibitor, and try again after the rain stops and everything dries out. Avoid repeatedly attempting to start the car, as it can damage the starter. I learned my lesson—now I always try to park in dry spots, maintain the electrical system regularly, and avoid similar troubles. When the weather is bad, I leave extra buffer time before heading out.
