At the part where Mel gets that special car to track down the bad guys, and in the big chase seen he hits a switch to give the car more power. Granted you can do this with Nitros injection, but what it activated was a forced induction system known as a Blower and is run by a drive belt thus is always on with no way to shut it off. Besides if it was off to begin with due to the tollerances in one of those things it wouldn't get any gas to the pistons.