Thanks! Yeah, it takes a good amount of force to actually take down one HP on the health/parts bar, and the icons just appear/disappear (so it doesn't really grab your attention very well).
I think you would know if phoenix rush was activated-- there's a loud sound effect and flames shoot out of the car :P I think I may have made the timing too tight on the button (you have 1/2 second between each press to charge it up, and it activates on the fourth press), or it could be that you were out of HP? It uses one HP to activate, and it won't do it if you have none.
Thanks for the feedback and for playing my game! I'll return the favor within the next day or two.