Why Won't My Car Start on Rainy Days?
4 Answers
The reasons why a car won't start on rainy days: 1. There is a problem with the ignition system; 2. There is a problem with the intake system; 3. There is a problem with the electrical circuit. After encountering this situation, you should immediately go to a professional institution or a 4S shop to have a professional technician read the fault codes to check the cause and location of the fault, and then repair it. The ignition system of a car engine is very important for the vehicle. The main components of the ignition system include spark plugs and ignition coils. Spark plugs are wear parts that need to be replaced regularly. As the usage time increases, the electrode gap of the spark plug will become larger. If the electrode gap becomes too large, it will cause the ignition energy of the spark plug to weaken, which can lead to the engine failing to start.
I've repaired countless cars in my lifetime, and failure to start on rainy days is particularly common, mainly due to moisture. Rainwater seeping into the engine compartment can cause electrical shorts—for example, if the ignition coil or starter connections get wet, the current becomes unstable, and the spark plugs can't ignite the gasoline. My advice is not to panic: first, open the hood and use a dry cloth to wipe the battery terminals and distributor dry. Sometimes, this alone can get the car started. If the battery is dead, use jumper cables to borrow power from another vehicle. For regular maintenance, frequently check the battery connections and apply a bit of petroleum jelly to prevent rust. When parking, choose a covered spot to avoid rainwater accumulation. Old starters are also prone to sticking, especially on rainy days, so regular replacement helps prevent this issue. Above all, safety comes first—don’t force-start the car if it won’t turn over, as this could flood the engine. Instead, seek help or consult a professional mechanic.
I've had similar troubles before. Last time during a heavy rain, my car wouldn't start no matter what I did, which was really frustrating. Later, a friend suggested it might be a battery issue - the dampness could have caused corrosion on the battery terminals, disrupting the current flow; or water might have gotten into the ignition keyhole, causing the car's computer system to malfunction. I ended up using a hairdryer to dry out both the keyhole and the engine compartment before it worked again. Now I make sure to maintain the battery properly, checking its condition before and after the rainy season, and keeping a portable jump starter handy. Temporary solutions: If the car won't start, wait a few minutes to let any moisture dissipate; if that doesn't work, call for a tow or assistance. I always keep a toolkit in the car with rags and multi-purpose pliers to handle such emergencies. Prevention is better than cure - parking in an underground garage is the most reliable option.
From an electronic perspective, car breakdowns on rainy days are often caused by circuit failures due to moisture. Rainwater reduces the insulation of wires, leading to damp spark plugs that cannot generate strong sparks; or it increases the resistance of starter coils, resulting in insufficient energy. I've encountered such cases during my work, where fuses blowing due to short circuits are a common issue. It's recommended to check if the ignition system is dry and to wipe key components; long-term maintenance should include anti-aging treatment for wires. Don't overlook sealing—water accumulation in the wiper trough can also seep into control modules.
