I had my HVAC PE like you before I took my FP exam. If you have any questions, let me know.
Some of the things you really want to know:
- I started studying in June for the October test.
- The best thing you can do is sign up for the SFPE class. It's a little expensive ($1495) but it's totally worth it.
- Compared to the HVAC test, I would say it's a little easier.
- Be patient with the reference materials. There are a lot of typos in the SFPE and NFPA Handbooks and they can be a little frustrating as you're studying.
- I made the transition from ME to FPE and it's opened up a lot of doors for me. I feel like I have better job options with the FPE than with the HVAC PE. But that's just my experience, YMMV
Anything else, just post it here.