Lein family

I'm having another problem finding people! Amund Lein b abt 1840 Norway, wife Mary b abt 1850 Norway. They emigrated about 1882 to 1885. I can't find them in any immigration, no Norwegian census....nothing! They ended up in Worth and Winnebago Counties, Iowa. Their children are: Anne b abt 1870, Osmund b abt 1874, Andrine b abt 1876, Soren b Mar 1878, and Oline b abt 1882/3....All these were born in Norway. 2 children were born in Iowa. Is there anyone who can help?! Please!! Thank you[:D]