I had a leak which I thought was the inflator. As soon as I went underwater in my shiny new (expensive) drysuit, I was wet around the inflator.
Ooops, found I'd not connected the drysuit hose. Must be that then.
Connected it and submerged again. Damn it. More leaking from that inflator. Grrrrr.
So got out and realised I was soaking. Got out of the suit and I was really wet, the undersuit sodden.
As I hung the drysuit up I noticed that the Si-Tech quick neck seal ring had popped out for about 1/4 of the neck seal! d'Oh. Check the neck seal!
Dried it at home and went back the next day. A dry drysuit. Yippee.
Moral of the ramble. It's not always the inflator. The water pools around your chest/waist/crotch.
Would suspect the zip. They commonly fail. It's amazing how small the holes are when you find them!
As
@Gone for diving said; it's possible that pressurising the suit will not identify the hole, for example if it's in a seam that seals with internal pressure.