What causes a sudden failure to start in a BMW 730?
2 Answers
BMW 730's sudden failure to start may be due to electrical circuit or fuel system malfunctions. Here are the specific details: 1. Electrical circuit malfunction: The phenomenon of electrical or electronic failure is very sudden, without any warning. Possible electrical circuit failures include: blown fuse, open circuit in the high-voltage coil, open circuit in the low-voltage circuit, detached central ignition wire, leaking distributor rotor, or damaged spark plugs. Electronic failure mainly refers to the loss of function in the central computer control board. 2. Fuel system malfunction: Engine stalling caused by fuel system issues often comes with symptoms like weak engine power or a spongy accelerator pedal. Possible fuel system problem areas include: fuel pump failure, blocked fuel line, clogged fuel filter, carburetor malfunction, or damaged injectors. Sometimes, it could also be due to an empty fuel tank that the owner is unaware of. Adding a few liters of gasoline may resolve all the issues.
I used to drive a BMW 730, and when it suddenly wouldn't start, the most common issue was the battery. After the car sat for a few hours or overnight, insufficient battery charge was the most frequent cause, especially since BMWs have many electronic devices that drain power quickly. That time in the parking lot when it wouldn't start, I got a jump start and it fired right up. It could also be a stuck starter or a failed relay—you might hear a clicking sound but the engine won't turn over. Ignition system failures are another problem, like spark plugs fouled with carbon that won't ignite, or a fuel pump that stops working and cuts off fuel supply. Electronic system errors, like a depleted key fob battery or an anti-theft lockout, can also prevent the car from recognizing the signal. Additionally, an overheating cooling system or faulty sensors might trigger a protective mode, causing a no-start. My advice is to try simple fixes first, like checking for loose battery terminals or replacing the key fob battery. If that doesn’t work, call for a tow to avoid draining other components. It’s best to regularly check the battery health at a 4S shop to avoid getting stranded.
