Wiring Problem

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Buckeyeboy

Buckeyeboy

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Hi. I'm fairly new to the forum and have spent a lot of time reading and learning so that I could learn to work on my barracuda and maybe help someone else. That being said I was wondering if someone could help me with my charging system. Last fall I decided to replace the wiring harnesses under the hood, the dash harness and replace the gauges with the redline reproductions. Ever since, when I start the car the ammeter goes to full charge and only comes back half way to the middle. The only time it will come back to center is with the lights, radio and blower on. The car is a '69 Barracuda that's been converted to MP electronic ignition. The VR is the old style with electronic internals and it has the round back alternator.
Based on what I've read in dozens of posts these are the results of my tests.
With key in on position...
Bat + to green connected wire at alternator 1.77
Bat + to fusible link .09
Bat + to red wire at bulkhead .24
Bat + to ammeter red .4
Bat + to ammeter black .43
Bat + to ignition switch black .47
Bat + to ignition blue .47
Bat + to ignition blue at inside bulkhead.53
Running warmed up bat - to vr case 0
Running with lights, radio and blower to vr case .1
Running at 1,500 rpm voltage at alternator stud 15.3
Running at 1,500 rpm voltage at battery 13.5
I also noticed doing these tests that the fused link and the short red wire leading to it get warm sometimes. I've been working on this all summer and am out of ideas. Any help is appreciated! Thanks
 
A....First...........do you have any loads (lights stereo etc) connected to the starter relay "big stud?" Doing so puts loads on the "wrong side" of the ammeter, causing this sort of reading


B....So far as your voltages.........
The two that really really matter and they "seem OK" is

1....With key in RUN, batt pos to blue VR or alternator field, as low as possible.

2....With engine running fast and charging, measured first with loads off and again with lights, heater, etc on, is batt neg to VR case

Both these readings should be very low or zero.

If I understand your post, they are pretty low? "Except" looks like .47--.53? If your VR is at 14.2 (let's say) that ADDS to the VR giving you a running voltage of 14.75, pretty close to 15. "Not all that bad" but still

C....You may have a sulfated or other problem with the battery. I would round up a "known good" battery and swap in for long enough to "tell"
 
67Dart273 said:
A....First...........do you have any loads (lights stereo etc) connected to the starter relay "big stud?" Doing so puts loads on the "wrong side" of the ammeter, causing this sort of reading


B....So far as your voltages.........
The two that really really matter and they "seem OK" is

1....With key in RUN, batt pos to blue VR or alternator field, as low as possible.

2....With engine running fast and charging, measured first with loads off and again with lights, heater, etc on, is batt neg to VR case

Both these readings should be very low or zero.

If I understand your post, they are pretty low? "Except" looks like .47--.53? If your VR is at 14.2 (let's say) that ADDS to the VR giving you a running voltage of 14.75, pretty close to 15. "Not all that bad" but still

C....You may have a sulfated or other problem with the battery. I would round up a "known good" battery and swap in for long enough to "tell"
Click to expand...
 
Thanks so much for helping me!
Nothing is attached to the starter relay.
I rechecked the blue wire with the white tracer at the ignition switch and got .3 then got .35 at the inside bulkhead same blue wire with white tracer. I'm not sure why it's different than the .47 and .53 I got last time.
With the key in run bat + to vr blue I got .45
Engine running at 1,500 no load I get 0 from bat - to vr case
Engine running at 1,500 with headlights, radio and heater I get .01
I replaced the five year old battery with a new one and nothing changed.
I also forgot that the previous owner wired a choke to the hot wire coming off the radio.
 
I would check the regulator for proper ground.
 
I thought measuring from the bat - to vr case both with with and without loads did that. I got zero without loads and .01 with loads. I did have to mount the vr from the back because the holes were stripped but I ran a wire from the case to the negative post.
 
Buckeyeboy said:
Thanks so much for helping me!
Nothing is attached to the starter relay.
I rechecked the blue wire with the white tracer at the ignition switch and got .3 then got .35 at the inside bulkhead same blue wire with white tracer. I'm not sure why it's different than the .47 and .53 I got last time.
With the key in run bat + to vr blue I got .45
Engine running at 1,500 no load I get 0 from bat - to vr case
Engine running at 1,500 with headlights, radio and heater I get .01
I replaced the five year old battery with a new one and nothing changed.
I also forgot that the previous owner wired a choke to the hot wire coming off the radio.
Click to expand...

It is starting to sound like you need a regulator which would be rare

The reason the batt---to ign blue changes is because any small "wiggle" in a ?? terminal OR THE ignition switch contacts themselves will change that drop. IE set up the voltmeter, and try "gently" wiggling the key while in "run." I bet the reading changes.

OTHER THINGS that change that reading:

Changes in LOAD on that circuit. "If you have" a choke heater, and the timer trips off, if you have break points ignition and the points are open vs closed, or the alternator brushes may be in a "poor" or "good" spot and drawing less or more field current.. In other words anything fed by the ignition switch "run" contacts that could change current draw.
 
I tried that and yes wiggling the key does change it by about .15. Do you think I should replace the regulator? It's only a year old but it is Chinese
 
This is starting to look to me like the only thing left
 
Replaced the old Chinese VR with a new Chinese VR. The only change is that the gauge doesn't peg the charge side but goes to the end of the scale then settles between charge and the middle
 
I wouldnt put any faith in an ammeter, a volt meter is more indicative of any problems.
 
I was a little overzealous in my reporting. The battery was low from all my testing. After putting it on the charger for a couple of hours and then running the car till its warm, the ammeter settles to one line to the charge side. I'm getting between 12.7 and 13.1 volts at the battery depending on rpm and load. I wonder what would happen with an American made mechanical regulator.
 
13.2 is voltage of new battery. 14.2 to 14.6 is optimum running voltage. If reg is properly grounded,and alt has proper ign power and wiring is correct there is no reason for it to not charge.
 
Changing the regulator made a big difference but now based on your numbers it's undercharging. Everything in the system is new or a year old. I'll go back and check the regulator ground. Thanks for your help.
 
Regardless of what a voltmeter says,known good battery, when car is running voltage needs to be minimum 1 volt above battery volts. So if your suspected faulty voltmeter reads battery at 11.5 with key off, then you want to see 12.5 with engine running. No less. Should hold that with loads on, fan,headlights and so on.

Perhaps a better piece of diagnostic equipment is in order.
 
When I posted that, I was referring to the ammeter because when I get 14 or a little more at the battery the ammeter shows a strong charge. When I switch regulators and get in the low 13's at the battery the ammeter reads closer to "normal" ( one line to the charge side). I really don't want to pull the cluster and swap the ammeter only to find it's not the problem. I find it interesting that each regulator gives me different results. All that being said, you did give me something to think about. I'll see about rounding up another volt/ohm meter and recheck the voltage running and not running at the battery. I'm using a $40 Craftsmen digital. Thank You!
 
Dont touch the ammeter.
Amps vs.volts. We are working on getting the volts correct,amps will follow.

When i dig into my dart and barracuda, both ammeters are getting bypassed. Volt gauge under dash.
It tells you everything. Condition of battery, starter ,voltage regulator and alternator.
 
This is definitely adding to my confusion.
2 brand new Voltage regulators.
#1 battery at rest 12.8
Warm at idle 13.3
Warm at 2,000 13.3
Load at idle 12.6
Load at 2,000 13.1

#2 battery at rest 12.8
Warm at idle 14.0
Warm at 2,000 14.1
Load at idle 12.9
Load at 2,000 14.1
I guess the second is closer to what I want. Maybe I should just drive it for awhile and see how the ammeter reacts
 
14.1 is close enough,its well into the minimum 1 volt over battery at rest.
Pay no attention to your ammeter. They are all good for nothing.
 
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