I have an 03 Neon that keeps throwing code P0204 and missing. Number 4 injector wasn't spraying so I swapped it with number 3 and it works fine there. I grounded the driver wire for number 4 and nothing so I grounded the other wire that goes from the injector to the coil and the engine died immediately and now won't even crank over. When you turn the key on there's power but no hum from the fuel pump and when you try to turn it over there is no clicking or cranking just silence. What did I do???

 

You shorted the ASD 12V circuit to ground. There should be a fuse, probably 25 amp that feeds it.

 

Thats exactly what it was, found it this morning. Thank you.