These are EhPro KF 2+ lites, right?
Did you tear them down and clean them first? Not from Fluid Vapes, and maybe wasn't even EHPro, but I had one some time back had a metal shaving blocking the air intake.
Try taking the air adjust screws all the way out, then use a straightend paper clip to probe both directions - i.e. in
through the intake and where the screw was.
And some have found that, with the dual intake ones, if you can't see
through the two intakes, you may need to "adjust" the 510 screw so you can. Has to be open for that, as you'll loosen the positive block. If they won't line up, you can use a small o-ring as a "washer" near the 510 screw head.