There is no solid scientific evidence linking the phase of the 11-year solar cycle to ENSO. There is also no plausible physical mechanism connecting the solar cycle to ENSO. (How would it work?) So I would argue that any relationship between the two that you have found, is due to luck using a small sample size. There was once a theory that El Nino is triggered by volcanic activity, and that is another example of an idea that bit the dust once more data became available.