8AWG. Done. I tried to buy 2 6-foot pieces, one with red and the other with green insulation. The green one ended up being 6AWG. What a beast. Really thick. Hard to wrk with, so I stuck with the 8.
Wish me luck tomorrow.
Cryoman
You will need to get some heavy gauge terminals in order to terminate the new wire properly. You might have to have a shop put them on that have the crimp tool to do that.
In order to reduce wire losses eliminate the side run to the horn relay and tie the new wire directly to the main fuse and then the battery so you have the least distance to the battery you can get. The horn circuit should tie to its’ own separately fused circuit from the fuse panel under the dash.
I re-routed the new 8GA wire in the same manner that it was originally. I didn’t put heavy duty terminals on it, which is a good idea. I’ll have to look into that.
However, I am still having trouble. None of the work I have done has solved the problem. I still have a voltage difference of apx. 0.7 between the battery terminal of the alternator and the (+) battery terminal. The GEN light still comes on at low idle.
Now, the carb is running poorly. I can’t rev the engine without it stalling out. There is also a problem with the choke system.
Anyhow, I’m going to continue tinkering and will provide updates and ask for advice when I can.
Thanks again
Cryoman
I should state that the voltage between the BAT terminal on the alternator is only high when the idle is low and the GEN light comes on. When the idle is higher (even around 1000 RPM engine speed) the GEN light is off, and the voltage between the BAT terminal and (+) battery terminal is about 0.27.
I decided that I am just going to replace the alternator, and after having taken it off, it is rather warm too. Must be an internal problem.
Lots of fun…life could be worse, of course. First-World problems.
Best-
Cryoman
I’m late to this discussion, but 4 feet of copper #8 is 2.6 mΩ. If you are seeing 0.7 volts across it, that is a current of about 270 amps, much more than the alternator is capable of, and enough current to badly damage the battery.
Aluminum wire or poor connectors would change that, of course.
My guess would be that the regulator isn’t working correctly, and the alternator is being asked to supply all it can.
"the voltage between the BAT terminal and (+) battery terminal is about 0.27"
This statement you made about the voltage drop doesn’t make sense to me. What BAT terminal are you referring to?
You say you still have about a .7 volt drop between the alternator output stud and the positive battery post. I’m not sure where you ran the battery end of the new output wire and if you check the voltage drop across the new wire I’m sure it will be pretty low. The remainder of the voltage drop will be the end of the new wire and the battery post. There should be a some sort of fuse in line so check the drop across it. There may be a bad connection there. I assume you still have a 12 gauge wire tied to the battery and if so that should be swapped out also.
I think I am getting my terminology mixed up.
I’m now having trouble keeping it running so it is hard to diagnose much at this time. The carburetor seems to be off, so, for instance, even when the engine and carb are warm, most of the time when it is at idle speed, if I open the throttle it acts like it is chocking itself out and dies. Often, the idle will drop down as if it is coming off the high idle and then dies. I can’t keep it running for any significant amount of time for me to determine if a problem still exists.
When I say the BAT terminal, I mean the terminal on the alternator where the wire runs to the battery to charge it. It is not a direct connection, as I have mentioned, but the wire terminates on a piece of metal that is part of the horn relay, and is apparently not part of the horn function, but just a place where several wires can connect that need the current from the battery. The connection to the battery goes to that place as well, although indirectly now, as the original circuit first travels through an aftermarket ammeter as discussed earlier.
Now, here are a couple of recent observations:
Having just put a new alternator in the car, during a recent idle, having placed the red wire of the volt meter on the BAT terminal of the alternator, and the black wire of the volt meter on the (+) battery terminal, the voltage now reads about 0.27, which appears to be what one would expect according to a previous post. However, the big issue now is that I can’t keep it idling. Seems to choke itself out when the idle speed drops, so I have to solve that problem before moving on.
I can’t say for sure that the charging system is fixed, because the readings I have taken may have been when the engine was running slightly above the RPM threshold where the apparent charging problem goes away.
I’m starting to feel like I am wasting everyone’s time now, so I’ll sign off and try to tackle the carb/idle problem and then get back to the charging problem.
Thanks for your continued advice.
Cryoman
BillRussell-just FYI, I have put a new regulator in the car before getting to this point. However, as others have mentioned, it might not be working properly despite being new. I need to see if I can test the terminals somehow. But, as mentioned, I have a hard time keeping it idling, so I am kind of stuck right now.
What is the battery voltage when the engine is not running, and when it is?
not running, around 12.5; running around 13.7. However, this whole issue started because when the car is at warm idle, the GEN light came on, and the voltage dropped back to the value of 12.5, as if the output of the alternator was terminated. I have replaced or cleaned nearly all of the wiring, just out on a new alternator, and did replace the voltage regulator.
the problem with the battery voltage may not have been corrected with the wiring replacement, as I saw that problem earlier today. However, since replacing the alternator, I can’t get it to stay running long enough at warm idle speed to see if the problem has gone away.
There are no electrical connections to the carb on this car, so I don’t think all of the wiring work I have done changed the carb at all.
Any immediate thoughts?
Cryoman
Those numbers are good. So the problem with running is not the battery/alternator.
If the battery is somewhat discharged I’d expect the alternator to be putting out more than 13.7 volts, more like 14.5 volts. If the battery is really discharged, more like 15 volts from the alternator. You don’t mention where that voltage is measured, at the alternator or at the battery. You say you have a 0.7 volt drop between the two, so where the measurement is made makes a difference.
Re high current wiring: I had a problem w/this on my Corolla’s starting motor circuitry (I’m responsible, I did some creative wiring to install a relay) which I could never figure out the cause, until I finally bit the bullet and carefully soldered all the crimped connections. That fixed the problem. Something to consider anyway. You shouldn’t be seeing a 0.7 volt drop between the alternator and the battery, and with 8AWG wire the problem isn’t the wire, so it has to be either the connections or the crimps at the connectors.
Sorry you are having difficulty, engine not running smoothly. If you have an electrical problem that could create a weak spark. But it sounds more like what you say, a carb problem. For ideas suggest to take a look at my recent thread where I had engine running and idling problems on an early 70’s Ford V8 and had to rebuild the carb to fix it, among other things. A carb rebuild on a 68 vintage Olds 442 being necessary from time to time is to be expected.
Thanks again, GeorgeSanJose-
I have been trying to do my best to get good connections. I have soldered each one. The last time I measured the voltage drop (from the BAT terminal on the alternator to the (+) battery terminal, it was about 0.27. That seems more in line with what someone else mentioned is usual. I’ll keep tinkering.
I am going to tackle the carb. I may use this as an excuse to teach myself how to rebuild it. In fact, before this weekend I had bought a good book on Rochester carbs (Doug Roe is the author). I’ve been frustrated by carb problems all of my adult life so now is the time for me to buckle down and figure them out).
I’ll keep you posted.
Cryoman
GeorgeSanJose- I should also mention that at times the alternator output does get up in the 14+ V range. I think that tends to be shortly after starting it when the battery is a bit drained.
When the engine is running, it is pretty smooth, so I don’t think there is a misfire. I also changed plugs and wires last weekend. The points are pretty new, but I have not tested the dwell angle yet. Hard to do when it won’t stay running for long
Good night
Cryoman
Thanks for the explanation of the wiring. From what you say now things are looking pretty good for the charging system. If the ammeter still has 12 gauge wire going to it then that will cause a fair amount of the drop you are now seeing. I would remove the ammeter and install a voltmeter if it was me.
For your engine issue I would have to guess either have a fuel delivery problem or a vacuum leak due to an open vacuum hose. You might see what happens as you open the throttle up slightly and use a squirt bottle to spray a small amount of gas into the air filter. If that helps then I guess you have a fuel problem.
Good morning.
A few updates.
The carb/running problem is solved. Got it running this morning, and when it began do stall, I sprayed a little starting fluid into the throttle, and it picked up again…fuel problem.
For a little background on this about which I posted last a while back, the car had been in storage for about 15 years. When I finally got it trailered to my new home and ran it a few times, the same symptoms occurred. I new I had an old gas and related issues, so I put in a new gas tank and replaced as many lines as I could. The stock steel lines are practically impossible to replace without having a lift and a lot of time (neither of which I had then). I left them on, and added a secondary fuel filter just in front of the fuel pump. When I took out the primary fuel filter that is housed in the carburetor, it was completely plugged with very fine, rust-colored material. (rust, i.e. oxidized steel probably). So, I installed a new fuel filter there too. I was prescient enough to buy 2 of these thinking it would not be long before the new one was clogged. Well, not long became yesterday. This new one was nearly clogged also. Added the new filter, and it runs good.
Unfortunately, the voltage issue has not gone away. At warm idle, the voltage between the BAT terminal on the alternator and the (+) battery terminal bounces between 0.1 and 0.3. While writing this, I decided to go out and check the battery voltage at different RPMs. When the idle is set high enough that the GEN light goes off, the voltage across the battery terminals is about 14.5ish. As I tune down the idle, that gradually drops, until it is in the high 12s when the idle seems normal for a warm car in Park.
I checked the voltage of the alternator from the BAT terminal to ground, and that seems to follow this pattern. Is that a clue? Should it or would one expect it to be around 14.5, as if it is putting out the appropriate current?
I am going to swap out the wiring for the ammeter and hook up wiring as it should be according to the wiring diagram and see if that solves this problem. Since the GEN light and buzzer seems to be doing its job, I may not install a volt meter. We’ll see. I want to get on to fixing other things after I solve this issue (tell me if that is unwise).
The good news is that the horn relay is no longer hot, and the voltage from the alternator to the (+) battery cable is much closer to where it should be. Hopefully one more re-wiring and that problem will be solved.
Thanks again everyone. I’ll be i touch
Cryoman
It seems the alternator is not putting out enough current to charge the battery at low idle. That is, the current out of the alternator is less than the load on the battery (ignition, lights, etc). With a fast idle, the output current increases enough so there is some excess current for the battery.
This would probably change if you turned the headlights on, for example.
In more detail, the voltage output of the alternator is controlled by the battery voltage plus any IR drops internal to the battery and in the cables. The internal no load voltage of the battery is about 12.6 volts (varies a bit with construction and temperature). As you draw current from the battery, the external voltage drops from 12.6 due to the IR drop of the internal resistance of the battery. If instead you are charging the battery, the voltage increases from 12.6 due to the IR drop of the internal resistance again, but because current is into the battery, the voltages add, not subtract.
An example may help. (neglecting any loads like ignition and lights)
If the internal R of the battery is 0.02 ohms and you draw 50 amps out of the battery, the apparent battery voltage would be 12.6 - (0.02)(50) or 12.6 - 1.0 = 11.6 volts.
If you are charging with 50 amps, the apparent battery voltage would be 12.6 + (0.02)(50) or 12.6 + 1.0 = 13.6 volts.
The latter number is at the battery. If there is an additional 0.01 ohms in the wires between the battery and the alternator, the alternator voltage would read 13.6 + (0.01)(50) or 13.6 + 0.5 = 14.1 volts.
Hope this helps.
As to the problem, it seems the alternator is not putting out enough current at low RPMs or the loads on the system are too high.
Re the former, it could be a bad alternator, or the wrong pulley size, or just the way the system was designed. I remember back in the generator days, pre-alternator, the light always came on when idling.
Re the latter, if that were true, something would be overheating, or, again, a design problem.
b
The engine issue did seem like the problem was due to a lack of fuel. Glad you got it solved.
All the new voltage figures you stated are GOOD and within reason. When the engine is at idle the output of the alternator has to go down also. It can’t produce the rated power unless you have the engine revved up some. Having 14.5 volts at normal engine speed is right where it should be. You don’t want to have more than 15 volts going to the battery, excessive charging voltage will cause too much charging current and will damage the battery. The fact that the horn relay doesn’t get hot means you corrected a bad connection there with the new wiring. One other thing you could do to check the voltage drop to the battery is to turn the blower and lights on high and then check the voltage while the engine is running around 1,500 RPM. If things are good you shouldn’t see more than around a 0.3 volt drop.
If you want to keep the ammeter that is fine as long as the proper wiring is used to handle the high current of the charging system. I would use the same 8 gauge wire you used since ALL the current from the battery has to flow through that meter. If the meter gets damaged somehow and opens then all power to the car will be out, dead. When a voltmeter is used it just needs some normal sized wire to operate it. The meter requires very little current to operate it since it has high impendence and it is in parallel with the power system and not in series like the ammeter is. A voltmeter will tell you all you need to know about the state of the charging system. If you do decide to install one then you just need to wire it in to power that is after the ignition switch so it turns off with the ignition power.
My knowledge of electricity is very limited, so I’ll just toss in my experience with waking up old engines that have not run in years and years. Rust and dirt in the fuel system is a nagging and difficult issue. Short of replacing every fuel line and the gas tank, do what you can to flush things out, then see if you can find an old style fuel filter that has a glass or clear settling bowl. You might get lucky at a boating supply place, because this is a more common problem in boats that sit for long periods. Those bowl type filters allow the rust flakes to settle off the filter mesh, out of the way, and you can open them, clean out the bowl, and put it back together.
I remember the glass bowls of long ago. You could really see if you had fuel getting to where it was suppose to and if there was any sort of contamination in the fuel.