German characters not showing properly on csv file using php

I am trying to generate a CSV file, which gets created perfectly except for the german characters ä,ë,ï,etc I just get the information to a $data variable and tried to use:

utf8_encode($data);

but I get weird text, h开发者_运维知识库ere are my headers for the file:

header("Content-type: application/octet-stream");
        header("Content-Disposition: attachment; filename=\"file1.csv\"");

I have tried using also iconv(); but no luck thus far.

EDIT

just noticed that my $data is already utf-8 so I removed the utf8_encode(); still, when I try to print it I get ?

and changed the header to:

 header("Content-Type: text/plain; charset=utf-8");

Use:

header("Content-Type: text/plain; charset=utf-8");

And make sure your $data isn't already utf-8!

Don't know, if this may cause the error: csv is an ascii-text file. You should use text/csv or at least text/plain. At all every text/*-mime-type is more useful, then application/octet-stream, because this defines binary data, what csv-files are obviously not.

Then if the file is already encoded in UTF-8, don't re-encode it

utf8_encode($data); // not useful, if $data is already utf-8

Next, add the charset to the content-type header

Content-Type: text/csv; charset=utf-8

(at all)

header("Content-Type: text/csv; charset=utf-8");

And last but not least: Make sure, that the application, with which you want to open the file, understand utf-8 and also uses it for the file.