Stiff starter has no life

 I've been following this forum for about 5 months now and appreciate all the good information available here. About 4 weeks ago I converted my 100% hydration starter 50/50 rye and bread flour to a 50% hydration starter. My goal is to make a more sour loaf of bread. I took 67 grams of the ripe starter and added 33 grams of flour 1/2 rye 1/2 bread flour, mixed and let it rise about 25%. I placed it in a container with plastic wrap and a lid then into the fridge. After 2 weeks I removed 5 grams and refreshed it 1:3:3 along with my 100% hydration starter. After 8 hours the 100% starer more than doubled while the stiff starter only made it to about a 75% rise. I repeated the refreshment with the same ratios and after 8 hours the 100% starter tripled and the stiff starter made it to double. I bake a loaf with both starters, same recipe. The stiff starter loaf did not rise as much as the other loaf but close. There was a very slight difference in flavor. 2 weeks later I attempted to repeat the same task. this time when I remove the stiff starter from the fridge it had a very sour smell to it, like vinegar, which initially I was excited about but when when I refreshed it 1:3:3 the mixture did not rise at all. I repeated with another piece of stiff starter and had the same results. Both starters are kept in the same fridge which is not used much so there is very little of opening and closing of the door. Any advice would be greatly appreciated.                                                                   

Vinnie