Mine has a very light scent, almost undetectable. You have to get right up to the flowers to notice it.

Good luck with the trumpet vine. I tried to get rid of it for 8 years without success. Now I just try and keep it along the back fence.

Do you have the double or the single variety? I only have the double rangoon and it is pretty fragrant. Not knock you down like night jasmine or anything but I can definitely smell it when it is blooming and I am anywhere in close proximity to it.
~SJN

The flowers on my Rangoon creeper are fairly fragrant when they first open, and are white. After they turn pink, not so much, and the fragrance is nearly nonexistent after they turn red.
Jim