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View Full Version : Alternator/Charging System Diagnosing Question...???


ESnacky6
08-18-2004, 08:57 PM
1965 Buick Riviera, 425 engine, new Optima yellow-top battery,
good grounds on battery and engine....

I know electrical stuff is much easier to some than others (me),
but here are my current symptoms....

while driving, my volt-gauge needle will 'bounce' or 'tick'
from about 12 to 12.5 volts or so, but never over 13...
(this happens with or without the stereo on by the way)

at idle, it has a tendency to drop to 11.5 to 12 volts or so...

Now when it's hot out, it seems to do this more often,
whereas when I'm driving at night, it seems to behave better,
not bounce much at all, and have a more steady charge of
12 to 13 volts at highway speeds...(still seems low)

I haven't checked the actual output with a multi-tester yet,
but I'm thinking it has something to do with the internal regulator
on the alternator... maybe it's on it's way out and overheating..?

The effects of this problem is that my battery doesn't always
get charged enough to be able to start the car the next time....
(kinda sucks ass on short trips, like just around town...)
I'm also waiting on a new mini high-torque starter, and until I get it,
I know I am also battling the PIG of a stock starter I have now....

So, without knowing the actual alternator output,
and just based on the gauge needle bounce/gauge readngs
does it sound like the alternator is the culprit..?
Anything else I should try to check..??

I'm just wanting/hoping to get initial reactions and thoughts
from people with experience, and/or similar issues in the past...

I hate electrical problems..... hahaha


Thanks a lot..!!! -Snacks....

shoebox72
08-18-2004, 09:15 PM
Your guage should be reading 13.5 to 14.5 volts. You can test the internal regulator on GM alternators by using a small screwdriver & sticking it in the hole in the back of the alternator that is shaped like a BACKWARDS letter D. touch the screwdriver to the housing while also touching the silver tab in the hole. This bypasses the regulator & will tell you if it 's bad by a higher voltage reading on your guage. But then again the 3 wire GM alternators are so cheap (so cheap, am I allowed to say that??) it's probrobly cheaper to just get a new or rebuilt unit put it on & forget it.

Your belt is tight, Right??

Billy

Phil Stevens
08-18-2004, 09:38 PM
[ QUOTE ]
but here are my current symptoms....

[/ QUOTE ]

sounds like your problem is not enough current http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif

ESnacky6
08-18-2004, 09:48 PM
Shoebox72,
yes the belts are definitely tight...
originally I thought that was the problem, as
we had just replaced the belts a month or two ago
and after a while they loosened up a bit....
tightened 'em up, and at first that seemed to do the trick...
but nope, the same things happened....

I'll check out the internal regulator though... thanks..!!

ESnacky6
08-19-2004, 07:37 PM
It'll most likely be Monday 'til I can make any progress,
anyone else have any advice or suggestions..?

I've been thinking about getting a new higher amp output
alternator anyway... like a Powermaster perhaps..?
just need to figure out which one I should order....
thinkin' either the 70/100 amp, or the 80/140 amp model...

Thanks..!! -Snacks....

lownslow
08-19-2004, 07:44 PM
sounds like its broken to me..........that's my professional diagnosis.............i could paint the alternator for ya ...... http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif

marq
08-19-2004, 07:47 PM
sounds like one or more of the diodes has gone in the back of the alternator,any good repair shop(electrical can do this for cheap)It don't sound like owt bad ,sometimes a blow out with a decent air line does the trick but while you have it out check to see if there are any visible signs of wear inside from the outside if you get my drift ok just look inside it without taking it apart..............Lol .........Marq

ESnacky6
08-19-2004, 09:26 PM
lownslow,
I've heard you do some really sweet paint jobs man....

How much to do some hard-ass tribal flames with metalflakes on it..?
I was thinking maybe purple, orange, and magenta colors, that match,
but make it spiralling in the direction of the pulley, you know..??
so when I lift the hood when it's running, you can like really
trip out on it man, you know what I'm saying..??
I'll be using bright yellow and blue belts too...

just wait 'til I come up with ideas for the other engine parts...
you'll be stoked..!!!



Later, Snacks.... http://www.jalopyjournal.com/ubbthreads/images/graemlins/confused.gif http://www.jalopyjournal.com/ubbthreads/images/graemlins/cool.gif http://www.jalopyjournal.com/ubbthreads/images/graemlins/wink.gif http://www.jalopyjournal.com/ubbthreads/images/graemlins/grin.gif