My V-air 380’s are acting up! one of them anyway. I re plumed my entire air system today. I turned on my air compressors and it sounded like one of them was working its @$$ off while the other one was real quiet. I did a test by pulling the fuse off of one and then the other. The one that is making all the noise is BARELY Filling the Tank while the other one (The Quiet one) Fills the tank up like it should. I think I might have over tightened the Check valve on one? If I did then is my air compressor finished?
Have you loosened the check valve that u suspect you have over tightened?
Did you use PTFE tape?! Have you tried disconnecting the compressor pipe and then tried running it?
AH HAH!!! I found the issue this morning!! I did In fact over tightened the Check valve! I loosened it about a turn and a half and now it is working EXCELLENT!!! And I also Didn’t have the air compressor line running from the air Compressor to the check valve tightened So it was bleeding air off as it was barely filling the tank! Whew! Thank Goodness 
You got lucky. Usually, once the check valve locks up - its stuck.
Glad to hear it worked out for you!