I was curious if anyone knows what is causing my car to loose battery juice?? I've replace the battery, alternator, and starter and even change out the main relay and both fuse box in and outside of the car. But if I was to put a new battery in then it will last me almost a month but then if it sits for just two days the car will loose battery juice and won't start. Also when I start the car up I can sometimes hear the fuel pump come on then sometimes it will not come on but if I were to tap on it the fuel pump it will cut on. When the car is turning I could hear a grinding noise coming from the motor and thought maybe I had a bad flywheel but check and flywheel is in good shape. A buddy of mine suggested me to change out my ignition switch that it may be the cause of my battery drain? Please help... cars been like this for about 3 years now and can not figure out what the problem is.

See if the link below helps:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-46563-3.html#post241804

Run the K-Test on your ECM at varying times. There's a real possibility that at the heart of your problem lies a failing ECM. The alternator control system, within the ECM, changes the voltage generated at the alternator (through the field windings), in accordance with driving conditions. Therefore, the voltage regulator and the ECM work together to manage the voltage generated by the alternator. The alternator control system in your ECM may be bad. This theory that you have a bad ECM could also explain the intermittent nature of your fuel pump not running, because the ECM (through the grounding terminal) controls the main relay's second relay. It's the second relay that controls the fuel pump. Try substituting a known-good ECM and see if the problems go away.