i would plug the plug wires and blow it out with air, same with the dist. cap, see if that makes a difference, if not pull the alt and have it checked at advanced or autozone, but i wouldnt think it would have hurt the alt, shyt ive sprayed acid on my engine to get the block and things to shine, even on the aly and it never hurt anything before, so i know purple power would damage anything as well lol