View single post by answerman
 Posted: 10-11-2012 06:41 am
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answerman

 

Joined: 09-10-2012
Location: Little Chute, Wisconsin USA
Posts: 435
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 Hello again.  Tonight, I decided, since I had an hour to kill, to try to figure out why Ms. Jenavieve's tach hasn't worked since I got her.  So, armed with the foldout wiring diagram from the owner's handbook, I started poking around (yes, I was finally introduced to the Lotus position).  I pulled the tach out and did some voltage testing on the wires... and they mostly seemed to test the way I expected them to (white and green were each 12v when the ignition switch was turned on, and the body of the tach was definitely grounded).

However, the white/slate (the one that runs from the tach to the ballast resistor) was only giving me about 0.7v.   From what I've been reading, that should be more like 9 to 10v.  Granted, I didn't have the engine running when I ran the tests, so maybe I am misunderstanding how the connection from the solenoid fits into the whole equation, but it appeared to me that I should have gotten some sort of backfeed through the ballast resistor to the white/slate wire connector.  Or is that connection only "hot" when the solenoid is actually engaged (i.e. during starting)?   Now that I think about it, that would make more sense...

Anyway, my question: what should the resistance of the ballast resistor be?  I haven't found any reference to it anywhere.  Should be easy enough to test if I knew what the resistance should be, and just trying to narrow down possibilities before I assume it's a faulty tach.

I had previously attempted a test by pulling the white/slate wire off the ballast resistor and trying to start her... and she would cough once and die, so I assume the resistor is doing "something".  Just not sure it's doing what it's supposed to.