Are you using a real R134 recover and recharge system or just the Wal-Mart special?
If its the AC in a can from Wally's you can't really go by that gauge. They aren't very accurate. I just put it enough to where my compressor is cycling properly and the AC is getting to the correct temp.
If its the AC in a can from Wally's you can't really go by that gauge. They aren't very accurate. I just put it enough to where my compressor is cycling properly and the AC is getting to the correct temp.