"I tried turning off the master, which disconnects the alternator from the essential buss, and the voltage on the non essential side spiked to 18V.  Realistically, this probably won’t kill anything, but I haven’t decided what I want to do about it. "

 ---

It will kill your alternator. It's running unregulated, that's why the 18V spike.  Mike C.

 

Yep, I figured it wasn’t good, but I don’t think it would be exactly unregulated.  It still has a voltage sense line that’s attached to the non-essential buss, so it knows what the voltage is.  Of course it loses the load of the battery on the line when you turn off the master, so that’s probably what causes the voltage jump.  I guess you could refer to that as unregulated also. 

 

Assuming that it’s bad for the alternator to power the buss without the battery hooked up, it would have to be even worse to let it power nothing, such as what would happen if you put a contactor inline with the alternator B lead.  Heck, I’m leaving it like it is, minus the switch. 

 

Cheers,

Rusty

 

 

PS- I found my injector problem.  The good news is that it was the connection in the cable, and should be fixed now.  It measured OK from the pin to the injector,  and it clicked just fine when manually powered, but I knew there was something wrong.  I decided to go ahead and take off the plastic connector cover, and found the connection loose.  It was being held more or less in position by the heat shrink, which was making some connection.  When I first cranked the engine yesterday, it seemed like it was working, then it dropped out.  Since there’s a decent amount of current on those cables, the poor connection was probably heating up, and getting dirty from arching.  If the threatening thunderstorm goes away, I’ll drag it back out and try it.  If all’s well, including my leaks, I’ll be off to the hanger by next weekend.