kalli

from what "67 evil eleanor" said:
at the battery post there is a tiny black cable going to the side of radiator. This is usually connected to the headlight. Can you confirm
Then there's the thick one, can't see what that is connected to. can you let us know?

what doesn't make much sense is the fact that your battery drains yourself when it's standing for a while but a test shows no current. From this I'd rather suspect that you are not properly charging while you're driving, arrive home on your last leg of your battery and it just won't start anymore the next morning (it probably wouldn't even start just after shutoff the night before).
Further you have more problems with your headlights one.
Since they had it tested, do we have any information on what amps the car was drawing with headlights on?

My opinion to all this is that it's nice to measure volts but useless when you should check for ampere and more important what direction. it would be great to know who much amp flow in what direction at idle, at 3000revs and the same tests again with headlights on. maybe your headlights suck so much power (corroded connectors, bad switch, connectors/cables) that the alternator simply cannot cope.

The last thing i want to do is saying bad things about a brand, but buddy of mine just fried one of those in your picture (after less than 1000 miles) ...

the first and foremost things to check:
do you have a proper grund wire from chassis to engine. If you do make sure you have a proper ground wire from battery- to chassis. It is likely you have as otherwise the car will have big problems starting (can't start when starter is not grounded through engine)

Second thing is the alternator belt. it has to be tight. so tight that you can just turn it 1/4 over it's own axis at the longest stretch yousing only thumb and index finger (obviously engine off)

then i believe there is a need of measuring the following:

ignition off: how many ampere are drawn
ignition on: how many ampere are drawn
headlights on: how many ampere are drawn
full lights on: how many ampere are drawn

This should already show bad connection in headlamp/switch wiring.

engine running in idle: how many ampere are drawn from bat OR how many ampere are we charging battery with
the same at 3000 rpm

as you said, the voltage is jumping around the place. is there any consitency to it?
I mean like: does it stay at a certain voltage in idle, does it stay at a certain voltage at 3000, does it stay at a certain voltage with headlights on

fakesnakes

Rewire the alternator/battery/solenoid as you have described. It will not fix your drain problem, but it will help address the one-wire sensing issue you are having. In basic electrical engineering terms, if you look at each wire as a resistor and the fact that there is a small amount of alternating current riding on the alternator output, you are not using the battery as a capacitive tank to flatten the ripple and it is affecting the ability of the internal regulator to manage the voltage output. Your wiring would be fine with a traditional 3 wire with a separate sensing wire to the regulator, but not optimized with your set up. You want the battery and alternator outputs meeting at the load (solenoid B+ terminal).

The troubleshooting tips given above on how to isolate your short are very good and should be followed. Good luck, these things are always difficult!

bodyputtyless

I'd be willing to bet that you have tapped a wire that supplies power to something associated with the stereo head and continuously draws. Make sure you haven't made a connection that is allowing some other circuit a straight path to ground. The stereo may indeed be turned off, but if you have used a power source that is continuously drawing you will wind up in the situation your are in. Also, make sure you have not removed ground wires from locations such as, headlamps,brake/tail lights etc. Removing the small ground wires can entice the electrical circuit to find the path of least resistance. This will cause a draw of power as well. Again, my money is on the stereo unit being accidently wired into a circuit that causes constant power use.

lefty3382

update:
so I found a cheap test light in my tools and so performed the same battery test as the shop. sure enough, the light went on when I connected the battery post and cable (both positive and negative) with the car off. So there is a draw somewhere. Why the test came back positive for me and not at the shop I have no idea. Now its just a matter of finding where the draw is coming from. As someone else suggested I removed the fuses one at a time and repeated the test, the light still came on even after all the fuses were removed.

At the shop the volt readings varied wildly from the high 12's to the upper 15's with the one exception being with the headlights on while the rpm's were high, then the voltage reading would drop to the low 12's. I will double check these numbers with my new multimeter.

Is it reasonable to assume the draw is somewhere in the headlight circuit since the drain becomes much stronger when the headlights are on? I will search for any bare wire touching metal, as well as any missing ground wires. The negative battery cable is secured to the engine block as it has always been, and I also have a ground going from the firewall to the rear bolt on the intake manifold, both of which were there when I bought the car. The stereo gets its power from the cigarette lighter wire, which the mechanic took care of for me in Van Nuys. Before that it was hooked up to a power source that disconnected every time I turned the car off.

I will change the alt/battery wiring as discussed, probably tomorrow. I'll go buy a multimeter as well.

I'm still exchanging my current alternator for the 140 amp, it won't arrive til next week but thats okay since I'll be out of town for Thanksgiving for the rest of the week starting wednesday morning. Progress!

bessemerengine

I would disassemble and clean every ground wire you can find on your wiring print. Make sure there is not paint under your ground lugs where the contact is made. Bad grounds can hurt your voltage regulator by spiking voltage as the connection makes and breaks. Bad grounds can create high amp draw much like a short.

kalli

when you buy a multimeter you might want to get one specif for cars that reads dwell and rpm as well (might come in handy at some stage). if you don't the absolute minimum to have is a multimeter that measures Voltage, curent and resistance (the usual volt, amper and ohm).

once you have that I can give you clear instructions on what to measure (after changing the cables like fake and evil said)

MDCCCCLXVI-Ragtop

Had the same problem on my 66. It ended up that the slide connectors attaching to the voltage regulator just weren't making good contact. Snipped them all off and replaced them and haven't had the problem since.

rst08tierney

How many COLD CRANK AMPS is your battery? Also what gage size is your ground wire?

I had a similar problem with my 67 and tossed out my 60amp alt and got 140 along with the largest CCA battery I could find which was the Optima (Red Top) which had 800 CCA. Problem solved.

To play things safe as well, I keep my car on a trickle charge when its not being driven. I have yet to have a problem since I changed the parts.

Im not a fan on the 1 wire alt my self. Keeping things OE for the time being until you locate the problem with your electrical system is your best bet.

lefty3382

So after determining there was a draw on my electrical system with the car off I spent the afternoon trying to figure out where it was coming from. I figured if I disconnected the right circuit or wire ahead of where the short is occurring then my test light wouldn't light up at the battery and I'd have my culprit. After trying many things, like removing my gauge cluster and disconnecting my headlamp switch, I discovered that the draw stopped when I disconnected my alternator.

So, why would my alternator cause a draw when the car is off? Could it be because the alt is chrome and is grounding to the engine block? If so, then why is running the headlights draining the battery? Is it just because its 60 amps isn't enough? Could switching my alt for a 140 amp that is powdercoated, which is what i'm going to do, solve this whole mess? If thats true, I will want to break something. Something expensive.

My battery is a Duralast Gold 750 CCA. Although its been drained somewhat and recharged so it might not be working at full capacity. Its still under a 3 year warranty which is how I got the last couple batteries I killed replaced for free. I'm not willing to spend the money on a fresh one while these problems continue anyway, for fear of ruining another battery. My battery cables are 2 AWG.

If all this does turn out to be because 1 or 2 bad alternators, it will make me less of a fan of the 1 wire units than before, but I'm not going to go through the trouble of switching it all back to stock without knowing for sure that this is the case.

I'll update again when I install the new alternator.

rst08tierney

Its crazy how many chrome engine components are complete garbage.