Is there a way to tell your DV is bad by messing with it off of the car?

Like if you blow ait into the intake side andand it comescomes out the top.. is that bad?

 

Check for cracks on the inside of the dia

 

put it back on the car, take your airbox cover and filter off, andgo run it. if it sounds like a raped goose you have a bad valve. also if it opens and releaves the pressure early (foot still on the gas) you have a bad valve.