I’m new to the board but it looks like you guys can sure help me. (I hope your’ out there Rockn-Roll).

I have a 1979 L-82 that won’t start. It has a new starter and good battery. I check the voltage on the battery and it reads 12.35V. Then I put it in the car and it reads just over 10V. Checked ground and all connections and they are good.

I have traced it down to the red wires coming off the starter B-Post. These are the wires that feed all of the car’s electrical system, except the starter. If I remove these wires I can get a 12.35V reading at the battery. If I reconnect them it drops to 10V – not enough to start the car even if I’m trying to jump it.

How do I go about finding out where my voltage loss is coming from?

Sure would like to be driving again!

:confused:

 

I hate to say this, but what you are noticing may be caused by your handling of the probes, as well as other bad connections....but in short form, it seems you have a bad frame ground connection/s.....the negative goes to a bolt with starwasher under the battery compartment, clean to bare metal and reinstall, up front on pass engne mount, there is a 6-8 inch grounding cable...
that needs cleaned and reinstalled,
then be careful how you handle and where you place your test leads...
reading 10 volts the way I read your note, means that battery would have to be near exploding if your connections were good, OR your testing/probe handling is leading to false conclusions....whichis easy to do in a corroded metal situation...

GENE

 

Try removing your fuses one at a time until you see the voltage return to normal. That will at least isolate the problem to a general area of the electrical system.

 

King, at this stage of the game, from my interpretation of what he posted...I would have to disagree with you, as those fuses are downstream of the fusible link and or fuse/breakers inline from the battery terminal on starter to the wiring harness.....if he has inadequate voltage at the starter when any 'load' is applied, I vote that in fact he has a bad connection still, maybe a bad wire terminal..same thing... or incorrect instrumentation...his meter seems ok, from what he said, so that means probe handling...
at this point, well any loading capable of reducing battery voltage to 10 volts in fact would exceed cranking amperage...that would instantly FRY any wires except the battery cables....

GENE

 

You're probably right! As I posted my reply I was having second thoughts along the same line as you. However, removing the fuses won't do harm but will remove anything down stream from the equation. Wait.... Now as I think through this I'm disagreeing with myself. That voltage drop would probably have blown the fuse in that circuit! So, yeah he probably has a problem ahead if the fuse block. :smash:

Ted

 

TED, :D :D :D :D :D :jester :jester :jester :sleep: :sleep: :cool: :cheers:

 

As long as we are on the subject of things electrical, how often does the ground strap problem show up in these fiberglass beauties? I am guessing that a grounding problem could appear as almost any electrical problem?

I have not seen it often on the forum, but it has to be crucial stuff. I have seen ground straps kits available. About 20 bucks for about 8 straps? (That is not the self-installing type. That would be more.)
In my 81 there is so much evidence of Bubba, I know that a groud strap analysis is something I better do before hitting the road...

 

Stevo, the body has 4 main bolts tying it to the frame, in front and two just forward of the rear wheels....I never seen any other grounding for the birdcage it'self....
the battery is as described, to the frame, and then frame with cable to engine...
headlights are to rad cross support, fans to engine/alternator if electrical...
blower and WSW to engine ground with too thin a wire, causing voltage drops...
rear lights to frame on driver's side.... inside, as I recall, two grounds, one above driver's kick panel to birdcage, other maybe under pass dash area somewhere....
I don't recall ever seeing any others.....
I redid the entire engine compartment and interior wiring last winter, did my own hookups and harnesses, simplified hell out of it, must have a drywall bucket full of extra wiring torn out....and same added for fuel injection/computer....even trade ....

GENE

 

Me again.

Thanks for the quick response. I’ll look at it again tonight but I did clean the main ground under the battery housing and also the ground at the starter. I may not be using the probes well, I kinda new at it.

I want to clarify one thing. When I measure the voltage on the battery, I get 12.35V. When I put it in the car, I get just over 10V – a loss of 2 volts and the only thing different is that it is in the car with the cables hooked. Then, if I disconnect the wires with the fuseable links, I’m back to the 12.35V. Which, I think, means I have a 2+ volt drain with only the dome light on (my a** is hanging out the door).

Also, for my information, how much voltage does the starter draw when everything is cool?

So is the problem upstream of the links or down stream or can you tell?
:rolleyes:

 

Blydy, YES, I have now reread everything you sent here, and from what you saying, it seems that any drain drops the battery voltage....well apparent battery voltage...try it with the headlights on....they should draw just enougn to burn bright yellow, and not drop the battery below say 11.5 volts, and only that low after a period of time...maybe 10 minits or so....
I think you have a bad/spliced battery cable....either at the battery connector end OR a splice in the hot lead, it's a long cable to that starter, and someone could have spliced it, and now it's corroded and no good connection...either that or you have a bad terminal end...very common, even in the sealed tips of a side post battery....
measure the battery voltage from the battery posts themselves, NOT the connectors.....and or the bolts into a side post battery....the bolts should of course be squeeky clean, literally, shiney metal...and then securely fastened down, check the inner contact point on the side post cables, shiney metal required also....same as for any other electricals....dull metal is corrosion and will drop voltage across any point like a stone....and get hot in the process depending on the current drain....
like I said my may even have a bad end terminal on the cable, not unheard of...

email me offline for direct help...

mrvette72@interstateweb.net

GENE

 

Wow...thanks. That's even a better answer than I expected. Your check is in the mail ! :seeya

 

Thanks for all the help Gene. It's running again.

Replaced the battery (old one was less than 2 years old) and that took care of it. Checked voltage with the car running and alternator is working too.

Thanks again! :cool: