After 3 days in the inability to start (for some reason), and my battery start to become increasingly weak from trying, I resolve to call a repairman at home, having no idea why it injects the failure occurs through the air box of the car and there miracle it starts. This product is really MIRACULOUS. For over worries start and suddenly I bought a bomb, always good to have on hand in case .... My car: Audi A3 TDI 2L. 170cv.