Hi, I have a 2003 adventurer 38g with the 8.1. I replaced the alternator as old one failed and since then I get a voltage of 15.5 down to 14.7 fluctuatring back and forth no matter the load. I measured at the chassis battery, with scan guage from OBDII and on ems panel. Any thoughts/remedies.
There is a voltage regulator built into the alternator that should limit voltage output to 14.4 volts. I would check the voltage with a second DC voltmeter to make sure it's not a incorrect reading voltmeter. If you get more than 14.6 volts with a different voltmeter then I'm afraid your replacement alternator has a bad internal voltage regulator and you'll have replace the entire alternator.
Randy - Manhattan, Kansas
2015 Vista 27N
2016 Honda HR-V