Hi, I'm a Wiening, originally from America but currently living in Austria and working in Liechtenstein. I also have done some modest research into my family roots in Germany.I've been able to locate ancestors in Martenshagen/Wiepkenhagen/Ahrenshagen/ Ribnitz-Damgarten (in what is now Mecklenburg-Vorpommern along the Baltic Sea coast) while I was stationed with the army in Berlin.Stettin is just across the border in Poland (I've been there too)so I would not be surprised to hear of some family connection in that area also.But I'm especially curious to hear about this town Wiening in Passau.
There is a brewery called "Wieninger Bier" in Teisendorf, southeastern Bavaria which is quite popular in towns like Berchtesgaden and eastern reaches of the Chiemsee.In fact, I just returned from a vacation in that area and stopped by the brewery again.
I looked on a few maps and did not locate Wiening, but I had heard from some relatives about this town in the past.If you have some coordinates (like, the distance and direction from Passau, names of surrounding towns, etc.) I'd be glad to take a look next time I'm in that part of Germany.