Illegal forward and backward passes thrown to conserve time (which means incomplete forward passes, and backward passes thrown out of bounds) cause the ball to become dead. Except inside 2-minutes in the 2nd/4th periods, by rule, the game clock will start on the referee’s signal, after the related distance/down penalties are enforced (LOD at spot of foul for intentional grounding; 5-yards from the spot of the foul with LOD for other types of illegal forward passes and illegal backward passes). Inside 2-minutes in the 2nd/4th periods, these fouls are subject to a 10SS (in addition to the distance/down penalties). If the 10SS is accepted, then the game clock starts on the referee’s signal. If the 10SS is declined, by rule, the game clock starts on the snap (which supersedes other rules).
Just wanted everybody to understand when the game clock starts after illegal passes. Keep in mind though, that time/score must be considered for passes outside of 2-mins in 2nd/4th periods (i.e, was the pass thrown to conserve time or yardage?). Most such passes will be to conserve yardage, so the clock will start on the snap.
Easy, eh?