The engine is on a hoist when he tries to start it up. Why start it at that point? When he tries to start it, it spits out a flame, so he tries to start it again. Then it catches on fire.

But it still isn't running. So he keeps trying to start the car, because that's a legitimate, intelligent decision. Of course, it won't start. His next move is to try and blow it out, because this is a lot like a birthday cake.

So he then goes and grabs a red gas can that is next to the Miata. It's his fuel tank, so presumably he's hoping to starve the fuel supply by taking it away. Yeah, that red can catches on fire. That then briefly sets his shirt on fire. Right now, this is what is technically known in the car world as a "cluster****."

Instead of putting out the now large fire with a proper extinguisher, he uses a hose. Thankfully it works and does put the fire out, which restores some order to the garage