1966 Buick Sylark not charging

[als66]

Good morning,

 

I have a 1966 Buick Skylark convertible with a 300ci 4.9 liter engine.  I purchased the vehicle in 2009.  When I bought it the car had a "parasitic draw" that would drain the battery.  I've tried new alternators and batteries and nothing works.  I am determined to fix this issue this summer.  In the past week I have purchased a brand new optima battery, a new alternator and a new voltage regulator.  The batteries displays 12.6 on the voltage meter but as soon as I start the car it drops so I'm assuming that it's starts at the alternator.  My question is, Does this car have a fuse that runs the alternator?  I checked the fuse box and they're were no bad fuses.  There's some kind of resistor connecting to the voltage regulator that I'm purchasing today.  I'm stumped and I'm tired of having to charge the battery every night and crossing my fingers that it doesn't die when I'm driving it.  So,  I can't use the headlights, the wipers or turn on the radio because the battery drains.  I tried to figure it out myself but I'm starting to lose my mind.  I'm literally getting a headache just writing this.  PLEASE HELP!

 

Al

[JACK M]

Did you try taking out the fuses one at a time in an effort to find where the draw might be?

I does sound like it may not be charging as well. Try for voltage at the alternator post rather than at the battery.

[TerryB]

When the car is running, what is the voltage at the battery?

[Bloo]

Should be 14.something volts when running.

 

When you turn the key on, but before you crank the starter, does the GEN light come on?

 

Does the light go out when the engine starts?

 

There wasn't a fuse on the alternator, but there very well could have been a fuselink in 1966. Look where the large wire attaches to the alternator, and at the other end of that same wire where it ends down at the starter. You should find it on the same post as the battery cable.

 

Edited June 14 by Bloo (see edit history)

[ABear]

9 minutes ago, Bloo said:

There wasn't a fuse on the alternator, but there very well could have been a fuselink in 1966.

To be clear, a fuselink is a special short piece of wire which acts like a slow blow fuse. It is typically several wire gauges lighter than the wire it is connected to and is there to protect the rest of the wiring from a short circuit.

 

Don't know how GM marks theirs but Ford would mark them with a big plastic flag on the end that attaches to a connection stud. Flag had fuselink on it and color of the flag identified the size. See first pix.

 

If no flags then wire may have fusable link printed on it like second pix, color generally identifies what the correct link is.

 

Blown fuse links can be a bit difficult to find visually so checking the voltage right at the alternator should be helpful and should be at least 13.8V when engine is running.

 

As far as finding your battery drain goes, a 12V light bulb wires in series with your battery will help identify the culprit. If there is something drawing power, the bulb will light up. You will do this when engine is not running.

 

Connect light bulb, if it lights or glows with key off then you have something drawing power, one by one remove a fuse at a time checking to see if the intensity changes or goes out with each fuse pull. Once light goes out, you have identified what circuit is drawing power and now you can start figuring out what all is on the circuit.

 

 

[rocketraider]

Visit here.

https://forums.aaca.org/forum/57-buick-post-war/

 

Then acquire these. Same books dealership mechanics used to service your Skylark.

 

There's usually several for sale on ebay, amazon or other sources at any time. Among other things it will have electrical wiring diagrams which will help you troubleshoot this problem.

 

Get an original print copy if possible. Reprints and digital copies often lose critical detail.

[Wascator]

With a cold engine and a charged battery, feel the alternator. If it’s warm, there is your parasite: the voltage regulator is not disconnection power to the alternator field on shutdown. Everything will work but it will drain the battery when sitting.

You can also disconnect the alternator wiring; if the drain stops, there you have it.

Edited June 15 by Wascator (see edit history)

[joe_padavano]

Let's back up. Did you first fix the parasitic drain? Shoveling money into new parts without first fixing the underlying problem is a great way to throw money away and introduce new and creative failure modes in the process.

[Frank DuVal]

I've worked on 1966 Pontiacs that did have a fuse in the harness on the engine going to the alternator. I've never seen one on a 1966 Chevrolet. Glenn is right, the 1966 Skylark shop manual should have information if a fuse was in there.

 

Joe is right, fix the parasitic drain. Gove box light, trunk light, and cigarette lighter (yes, they can start drawing small current as to not get hot but still drain the battery, simply pull it out and see if problem goes away) are prime suspects on a 1966 Buick.

 

Connect 12 volts to alternator's F terminal while monitoring voltage at the nut/bolt terminal of the alternator. It should jump to full output which might be 16. 17 volts! So, just a quick test, do not leave the jumper on. No increase in voltage? Then alternator bad. 

[EmTee]

8 hours ago, Frank DuVal said:

...and cigarette lighter (yes, they can start drawing small current as to not get hot but still drain the battery, simply pull it out and see if problem goes away)...

Check the lighter socket for a wayward penny or dime.  The front ashtray was often used as a piggy-bank for parking, toll, or phone booth (remember those?) change.  It wasn't unusual to have one of those coins find its way into the lighter socket...