K.B.
I would suggest trying some days of putting her down to nap even faster, because often if she is already tired and cranky when she's going down then she's overtired. Overtired babies have a chemical released in their brains to keep them up and it's hard for them to get good sleep. It's possible that she is having these short naps precisely because she is too tired. So although only an hour and a half of awake time seems really short, maybe she needs a smaller window of awake time, especially for the first and last naps of the day. I used the Weissbluth book, but what's best to take away from him are a few choice nuggets: sleep begets sleep, put them down earlier than you think, and learn to catch your baby's wave of sleep. My two kids were a little different: my son could stay up for longer and my daughter was toast after 90 minutes. Each kid is different and the book is only a guideline. Try nudging her naps a little sooner, say by 10 or 15 minutes, so you're putting her down when she is just starting to get drowsy, NOT when she's cranky. I hope it helps, good luck! Also remember that she could change her sleeping habits on her own one day no matter what you do, so try to shake off that feeling of failure!