If an alternator dies on a SA does it make the tach act weird?
10-10-09, 07:30 PM
#1
If an alternator dies on a SA does it make the tach act weird?
I've never had an alternator die on a 7 until now and some peculiar happened. When I start the car, a '79 with Volt/Tach combo, wherever the tach was positioned to read voltage it sort uses as 0rpm and doesnt fall back down. In other words it hovers up around 6k and the volt meter doesnt turn off. Is this caused by the alt failing or something else? Also, GEN OIL and i think parking brake lights stay on.
any ideas?
Shawn
any ideas?
Shawn
10-10-09, 11:10 PM
#4
Yep. Probably an alt issue. With the '79, there could also be a problem with the external voltage regulator (if you are still running the stock alt).
What happens is the alt send a signal to the choke & check relay to tell it that it is charging. This relay is what switches it between volts and tach. Also, when not charging, the lights that you mention will also be on.
One quick thing to also check: make sure that the alt belt isn't broken. That will cause the same issues and it is a lot cheaper to fix if that is the problem.
If you do replace the alt, I would recommend going with a later model so that you get the internal voltage regulator (unless you are wanting to keep it all original).
What happens is the alt send a signal to the choke & check relay to tell it that it is charging. This relay is what switches it between volts and tach. Also, when not charging, the lights that you mention will also be on.
One quick thing to also check: make sure that the alt belt isn't broken. That will cause the same issues and it is a lot cheaper to fix if that is the problem.
If you do replace the alt, I would recommend going with a later model so that you get the internal voltage regulator (unless you are wanting to keep it all original).
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