Hahaha, happened to me. I was all ready and set and happy with my first ever nitrous install and it didnt work. Took me 2 days to figure that out, the dumbest thing can turn into a nightmare. Now i love my spray but i havent used it alot, i have alot of respect for it.

 

I never said there can't be nitrous backfires. Hell, I was shooting a race and the car backfired so hard that it blew the fiberglass front end right off the car and put a 10" hole in the plexiglass windshield, and I was standing 5 feet behind it! I have rarely seen one caused by just fuel alone.