I just dealt with a similar issue. I think the big clue here is that when you switch on the ignition your voltage drops to 11. You've got a big voltage drop somewhere - check your battery voltage under those conditions and it'll probably be well over 12. On my car the crimp terminals at the alternator and at the master cutoff switch were corroded. Check each connection with a volt meter across the connection while current is flowing - an ohm meter won't show the problem. Check from the alternator + to the battery + and from the alternator case to the battery -. Track down where that voltage drop occurs.
I also had underdrive pulleys on both the crank and the alternator - removed the one on the alternator. With all the fixes now my full load battery voltage is about 1 volt higher than it was.
Marty Doane
ITS RX-7 #13 (sold)
2016 Winnebago Journey (home)
Bookmarks