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Topic: Good news and bad news

in Forum: C3 Electrical

Good news and bad news

Posted: 12/12/12 9:54pm Message 1 of 36
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Vancouver, WA - USA
Joined: 8/25/2005
Posts: 869
Vette(s): 1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.
Good news: I think my battery is OK.
Bad news: something else is wrong.  

I haven't driven or started it for about 3 weeks.  Batt has been disconnected with the quick release, but it was NOT on the trickle charger.  Last night out of curiosity I hit the key for a second or two before I hooked up the charger - plenty of cranking power.  In the past a few days of sitting with the batt connected and it will kill it.  So that tells me there's some parasitic drain going on - hmmm.  Any thoughts about where to start or what the most likely culprit is?  Factory alarm maybe?  




 

1976 Silver/Firethorn.  L48, 4spd.  Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.
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Re: Good news and bad news

Posted: 12/12/12 10:25pm Message 2 of 36
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Grapevine, TX - USA
Joined: 8/26/2006
Posts: 1522
Vette(s): 1972 LT-1 convertible with factory air. 2017 Black Rose Grand Sport convertible.
I don't know Bo about electricity, but you could try testing for current at the fuse box with the ignition off.


   

Re: Good news and bad news

Posted: 12/13/12 4:23am Message 3 of 36
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Cramerton, NC - USA
Joined: 8/22/2006
Posts: 1094
Vette(s): black 1982 coupe slate gray interior, 350 crossfire, 1985 fuel pump, Steeroids R&P conversion

Im not an electrical guy either but some of the guys here are will probably chime in shortly.  Instead of giving my own advise, Im posting a link to a pretty good electrical troubleshooting post from another forum.  If I offend the forum gods by posting from another forum I apologize in advance.  Scroll down a bit to the post by ...ROGER...  Hope this will help you some.

http://forums.corvetteforum.com/c3-tech-performance/1783718-battery-dies-in-my-82-cant-locate-cause.html


Re: Good news and bad news

Posted: 12/13/12 7:16am Message 4 of 36
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Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20214
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas
Parasitic draw on these old turds will definitely drain a battery after a few days....most of us have just come to accept it, and use the quick dis-connects on the batteries.
A couple of the most common drain problems are the clock, and the alternator. The alarm systems can also cause excessive drain, but there are usually other symptoms associated with that, such as an alarm that don't work, or blows the horn all the time. Un-plugging the relay will tell if it is an alarm issue.
Aftermarket stereos and other additions can also be a source of excessive drain.
These cars are old....with old wiring and stuff. Battery drain is part of the joy of owning them....LOL NOT!



Joel Adams
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Re: Good news and bad news

Posted: 12/13/12 10:29pm Message 5 of 36
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Vancouver, WA - USA
Joined: 8/25/2005
Posts: 869
Vette(s): 1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.
Thanks, guys!  Good info.  Joel, you might be on to something with the clock.  When I was putting everything together this summer I fiddled around with my two mechanical clocks and got one of them working.  It even worked for a few weeks or so after I got it in.  But now it don't.  Possibly it's still causing a draw?  Chip, your link to the "other forum" was helpful, too.  (don't feel bad, I lurk there sometimes, but you do have to wade through a lot of infighting).  They mentioned the mechanical clocks on there, too.  I'll get out the test light and start playing around with stuff.  

In any case, a quartz clock conversion is high on the to-do list now for this winter/spring (even if it's not the source of my current problems)




 

1976 Silver/Firethorn.  L48, 4spd.  Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.

Re: Good news and bad news

Posted: 12/14/12 1:08am Message 6 of 36
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Cramerton, NC - USA
Joined: 8/22/2006
Posts: 1094
Vette(s): black 1982 coupe slate gray interior, 350 crossfire, 1985 fuel pump, Steeroids R&P conversion
Dave, you are right about the "other forum", lots of good information there but also lots of egos and attitudes.  I lurk but rarely post there and consider C3VR my home, Im comfortable here.  Good luck with finding your current draw.


Re: Good news and bad news

Posted: 12/14/12 5:35am Message 7 of 36
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spicewood, TX - USA
Joined: 9/13/2009
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In my past experience, I have found that it can often be caused by a faulty starter.  A dead spot.  I am not saying that the starter will even show any signs of an issue even.  But it will draw your battery down.  The best way to know is to have it tested.  Which is a PITA.  You can disconnect the positive lead from the solenoid, and let it sit.  If it does not drain then you have ruled out the soleniod. And a short in the switch on the steering column.  Then disconnect the main battery cable and do the same. Sit for a couple of days and see if it drains. If it doesn't then the starter IS likely the issue.
 
Then check anything that may be direct wired to the battery. (ie. Stereo equipment, etc.)
 
It could be a dead cell in the battery as well.  Have had them show a full charge, but when you start cranking on it, that dead cell will show its ugly head.  I always look at a battery issue as the culprit if it is more than 3 years old.  Does not matter what the rating is.  After three years it is russian roulette.  If it is taking a charge everyday, by driving, or trickle charging, you won't notice it.  But a dead cell will drain the battery while it sits.  Whether it is connected to the system or not.  Have it checked.  They usually do not charge for it, and if you have quick connects, they can check it in the car with no issue at the local parts house.  Most of them anyway.
 
Hope this helps.
Mike




 

Re: Good news and bad news

Posted: 12/14/12 1:34pm Message 8 of 36
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CUYAHOGA FALLS, OH - USA
Joined: 12/2/2003
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Vette(s): 1975 C3 Red, T-Tops, Black Interior. All I need is time and money! Getting there!
Mine can sit for two months with everything connected and still start.  You don't have to live with it.
 
Get an inexpensive amp meter if you dont have one.   Many digital meters will read amps, some won't.
 
Disconnect the battery and connect the amp  meter in line between the battery and the cable you disconnected.  If you are over 0.3 amp, you have a problem.  The lower the better.   0.5 amp will kill the battery overnight.  Ideally it should be less than 0.1 amp.
 
A volt meter will NOT work for this.  I will avoid the explantion at this time.
 
Now watch the amp meter and start disconnecting fuses, one at a time.  If at any point the meter reading drops, you have found the circuit with the problem, and you can start disconnecting items on that circuit until you find the draw.  Be sure to have the interior lights turned off or they will show a draw that is not there when you shut the doors and walk away.
 
If all fuses are out and you still have the electrical draw,  disconnect the alternator, and then the starter.  By this time you will have found the problem.   It may take you a few minutes, or a few hours, but you will know for sure, and you can correct the cause.
 
Happy hunting.



Re: Good news and bad news

Posted: 12/14/12 8:55pm Message 9 of 36
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Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20214
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas
NO disrespect to anyone, but....I'm not getting this one...
Disconnecting the cable from the starter will effectively kill ALL power to the car, so...there would be no drain at all...kinda like disconnecting the cable from the battery. Unless I'm missing something from the Zenmaster's, or the previous posts. Unless you keep the pink feed wires connected to the disconnected main starter cable, that is....
Did I miss something, or is my pea brain really that damaged from the '70s....Wacko LOL LOL

Using an amp meter and pulling fuses will certainly find the cause of excessive drain....but I'm just too dang lazy...and not flexible enough to hang upside down under the dash pullin fuses....LOLLOLLOL

Good to see ya on the forums again, Ken! Hug



Joel Adams
C3VR Lifetime Member #56    

My Link


(click for Texas-sized view!)
             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

Re: Good news and bad news

Posted: 4/11/13 10:53pm Message 10 of 36
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Vancouver, WA - USA
Joined: 8/25/2005
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Vette(s): 1976 Silver/Firethorn. L48, 4spd. Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.
So I finally started doing some diagnosis on this problem.  It looks like it's the courtesy light circuit.  With an ammeter inline on one of the batt cables I pull about .33 amps with the doors and hood closed and all (that I know of) courtesy lights off.  If I pull that fuse, I show no current draw at all with the same conditions.  Any thoughts how that particular circuit would draw current with all the lights off?  Is there something else on that circuit?

Oh, and the clock has not been plugged in for any of these tests.  I was going to put my center cluster back together tonight but decided I better do this diagnosis first while I have access to the back of that panel.  

Thanks guys!




 

1976 Silver/Firethorn.  L48, 4spd.  Original 2 bolt, vortec heads, 9.4:1 CR, Speed Pro Cam: 224/224@0.050, 112 LSA, Eagle Steel Crank.

in Forum: C3 Electrical


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