▁model ▁ 7 2 0 0 ▁Variable ▁Vent uri ▁( V V ) ▁Car b ure tor . ▁ ▁This ▁was ▁the ▁last ▁car b ure tor ▁designed ▁and ▁built ▁by ▁Ford ▁US . ▁ ▁It ▁was ▁considered ▁to ▁be ▁the ▁p inn acle ▁of ▁car b ure tor ▁design . ▁▁ ▁Air - f uel ▁ratio ▁was ▁controlled ▁by ▁a ▁ste pper ▁motor ▁that ▁operated ▁a ▁ra ck ▁which ▁moved ▁a ▁pint le ▁that ▁opened ▁and ▁closed ▁the ▁float ▁bow l ▁vent . ▁ ▁When ▁closed , ▁no ▁air ▁could ▁enter ▁the ▁bow l , ▁causing ▁the ▁fuel ▁mixture ▁to ▁be ▁lean . ▁ ▁When ▁open , ▁the ▁fuel ▁mixture ▁was ▁rich . ▁ ▁While ▁this ▁car b ure tor ▁worked ▁well , ▁it ▁was ▁extremely ▁expensive ▁to ▁manufact ure . ▁ ▁Each ▁car b ure tor ▁was ▁hand - cal ibr ated ▁in ▁a ▁pressure ▁controlled ▁room . ▁ ▁Although ▁there ▁was ▁much ▁in ▁common ▁" inside ▁the ▁box ", ▁the ▁size , ▁shape ▁and ▁main ▁conne ctor ▁were ▁different ▁between ▁E EC ▁I ▁and ▁II . ▁ ▁The ▁processor ▁design ▁was ▁significantly ▁upgrad ed ▁as ▁a ▁candidate ▁for ▁use ▁in ▁E EC - III ▁but ▁was ▁not ▁chosen . ▁ ▁E EC - III ▁ ▁This ▁system ▁is ▁used ▁on ▁certain ▁ 1 9 8 1 - 8 3 ▁models . ▁There ▁were ▁two ▁different ▁E EC - III ▁modules : ▁Fe ed back ▁Car b ure tor ▁( F BC ) ▁and ▁Central ▁F uel ▁In jection ▁( C