18v overcharging!


New member
New to forums so sorry in advance if i break any protocol im unaware of. So i just bought a 93 xj 4.0 with a automatic transmission and now im having a overcharging issue, everytime i floor it the idiot gauge just about pegs to 19, normally it will settle back down after a few seconds and go back to 13.7. One day it pegged after i floored it and stayed there so i cranked the heat turned on the lights to drop the voltage a little and limped it home. Grabbed the ol meter and sure enough battery was at 17.6. I ran to oreillys they hooked it up and said the battery came back good, alternator came back good and its a bad voltage regulator. Id rather not replace my pcm if i dont have to so im hoping someone has an idea as to what this can be. Also i let it sit for a while came back out and then everything was back to working normally but again when i floor it my battery goes up to about 18.