Engine power supply system. General information (BMW 3 Series E30)

The engine fuel system includes the fuel tank, fuel lines, fuel filter, fuel pump and carburetor or fuel injection device with air filter.

The fuel tank is divided into two parts and is located behind the rear axle. The fuel level in the fuel tank is indicated to the driver on the dashboard. The fuel tank has a ventilation system.

To refuel with unleaded fuel, the following conditions must be met.

The valve seats in the cylinder head must be made of hardened material, otherwise the seats will wear out quickly. Additional installation of hardened valve seats is not justified due to high costs.

Since unleaded super gasoline has a maximum octane rating of only 95 (leaded super gasoline: 98), a "later" ignition timing should be set to prevent engine detonation. As a result, engine power decreases and fuel consumption increases.

It is recommended to consult a service station about how much the ignition should be set.