Yugo engines were fitted with a carburetor until well into the 1980s before fuel-injected models (starting with the Koral 65) were introduced beginning with the GVX-EFI (an Electronic fuel injection system), which featured a 1300cc engine.
Первым автомобилем «Заставы» с инжекторной подачей стал Koral 65, а вскоре появилась и модель Yugo GVX-EFI с двигателем в 1300 см³, в которой EFI расшифровывалось как «Electronic fuel injection» ().