The solution of BMW 525 cylinder shortage depends on the root of the problem. Some possible problems and solutions include: 1. Oil supply problem: make sure the fuel pump works, check whether the fuel filter is blocked or not, and check whether the fuel pipeline leaks oil. 2. Ignition system problem: Check whether the ignition coil, spark plug, spark plug coil and other electrical components are normal to ensure the smooth circuit. 3. Engine control unit (ECU) failure: If ECU failure is found, diagnostic tools need to be used for diagnosis and maintenance. 4. Air intake problem: If the air filter is blocked, it may lead to insufficient air entering the engine and affect the normal operation of the engine. 5. Other mechanical failures: such as engine cylinder wall damage and poor valve adjustment. Need mechanical repair. It is suggested that when faced with this situation, you should go to an experienced maintenance technician for diagnosis and maintenance as soon as possible, so as to ensure that the problem can be repaired in time and avoid damage.