The situation is as follows: I am a third year PhD student in theoretical biophysics and recently had my first jointly-authored journal paper published. My advisor thinks that I am on track, though to be fair a lot of the credit goes to another student who did a substantial part of the work for the paper. In any case, before working on this paper I was working on a completely different project, which my advisor asked me to abandon in order to work on this paper. We never talked about the previous project again.
Now I am wondering what I should do with the previous project. I have quite a fair amount of results and put several months of work into it. However, it is hard for me to put the results into context and even convince myself that they are interesting enough for a publication. My advisor is not an expert on this particular topic, and I think that to convince him to revive the project I would have to come up with a brilliant idea of what to do next (which I also don't know at the moment).
So I am torn about whether I should put more effort into trying to revive an old project my advisor told me to stop working on or to give up the project altogether. The last option would be a difficult decision, because of all the work I put into it, but if I can do better research instead and it does not hurt my chances of finishing my PhD on time, I would be able to accept it.