What Causes Engine Shaking After BMW 5 Series Drives Through Water?
4 Answers
Reasons for engine shaking after BMW 5 Series drives through water: Minor water ingress in high-voltage wires: When water enters the vehicle, small amounts may penetrate the high-voltage wires. The engine air filter element becoming soaked increases intake resistance and allows water into the combustion chamber, resulting in poor ignition system performance. In severe cases, spark plugs may fail to ignite, potentially causing the vehicle to stall. Excessive water depth: Driving through excessively deep water affects exhaust through the tailpipe. Open the hood and inspect the air filter element for moisture - if dry, the vehicle can be used normally. When water submerges the exhaust pipe, significant power loss occurs. If acceleration becomes ineffective, maintain high throttle through the water without shifting gears mid-process.
I've been driving a BMW 5 Series for several years, and the shaking after wading is mainly related to water entering the engine. If water is sucked into the cylinders through the intake, the pistons hitting water can cause engine shaking, a phenomenon that often occurs during rainy days or when there's standing water on the road. Wet spark plugs or ignition coils can also lead to unstable ignition, making the car jerk while driving. BMW engines are quite precise; once water gets in, electronic sensors like the crankshaft position or air flow sensors may send erratic signals to the computer, leading to inaccurate control. There's also the possibility of water accumulating in the air filter box, blocking the air passage and affecting the combustion of the air-fuel mixture. In severe cases, it can damage the cylinder block or cause cylinder scoring, which is expensive to repair. I recommend not forcing the engine to start after wading and instead towing it directly to a professional repair shop for inspection. They can use diagnostic tools to read fault codes and analyze the root cause. When driving, it's best to avoid deep water areas, and regular maintenance of the air filter and watertight components can prevent such issues.
As a car enthusiast who loves studying technical details, post-fording shaking may stem from water residue affecting the electronic control system. BMW's numerous sensors are often installed in low positions, where splashed water could short-circuit components like the crankshaft position sensor or ignition module, sending false signals. When the ECU receives erroneous data, it disrupts ignition timing, causing rough engine operation and vibrations. Additionally, moisture in high-voltage coils weakens spark intensity, leading to incomplete combustion that exacerbates shaking. Water accumulation in the exhaust system might also be sucked back into cylinders. In severe cases, the computer may enter protection mode with false fault judgments. If shaking occurs after fording, immediately shut off the engine to prevent further component damage. You could try removing the key to air-dry for several minutes before restarting, but the best solution is prompt towing to a dealership for multimeter testing of resistance and insulation. For prevention, monitor water depth - avoid fording when levels exceed half the wheel hub height.
Stop the car if it shakes after wading through water; don't force it to drive. Water entering the engine compartment can affect combustion, and the piston movement will be hindered, causing shaking. The BMW 5 Series has a lower air intake position, making it prone to sucking in water. Wet spark plugs or short circuits in the ignition wires can also cause this issue. Continuing to drive may lead to cylinder scoring or engine damage, which is expensive to repair. It's safer to turn off the engine immediately and have it towed for inspection.
