Audi TFSI Engines Suffering Deadly Problems? by Ollie Published Updated If you’re considering a new VW or Audi with . litre TFSI engine, then you may want to think twice before signing on the dotted line..Discussion forum for the rd generation cylinder . liter turbocharged direct injection TSI VW TFSI Audi engine. This forum is sponsored by COBB Tuning..FSI TFSI principle At Audi, FSI stands for gasoline direct injection, a technology in which fuel is injected directly into the combustion chambers, rather than into the intake manifold in the traditional manner..Tfsi Turbo fuel stratified injection or TFSI combines petrol direct injection with turbocharging. Compared with conventional naturally aspirated V engines, a turbocharged direct injection four cylinder engine delivering the same performance uses percent less fuel..