i was recently working alongside an aircraft mechanic on a turbocharged 6 cylinder fuel injected engine (a Lycoming TIO-540 if your curious) and the complaint from the customer was that it would occasionally hiccup when run in cruise. Maybe once or twice a day for a 10hr per day operation.
What the mechanic showed me was a pressurized air line leading from just after the turbocharger to each of the fuel injectors. He found some fuel in this line, and stated that was likely the cause. However, when i asked him why that line was there, he didn't know the function, just that he has seen contaminants in there cause past issues.
I can't for the life of me figure out why each injector would need a pressurized air line from the turbo. Any ideas?