1972 Audi 100 Series Engine: 1.9L L4 GAS; Position: Air Pump;. 1975 Audi 100 Series Engine: 1.9L L4 GAS; Position: Air Pump;. 1973 Audi 100 Series Engine: 1.9L L4 GAS; Position: Air Pump;. 1974 Audi 100 Series Engine: 1.9L L4 GAS; Position: Air Pump;.