The 33-year-old Finn shot a 7-under 65 in wet conditions Saturday to move to an overall 18-under 198 on the Bro Hof Slott course.
The 114th-ranked Ilonen, whose last Tour victory was winning this event in 2007, had back-to-back birdies at Nos. 13 and 14. He then eagled the par-5 15th when his short wedge shot into the green spun back into the hole.
Noren posted an 8-under 64.