Voltage @ cruise

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rumblefish360

rumblefish360

I have escaped the EVIL Empire State!
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I have been having electrical issues as of late. (Woo-Hooo!) On the Magnum. ("79)

There also could be a fuel delivery issue as well. I just have not gotten there yet. But anyways. I was going though a bunch of voltage regulators. The Alt. was hammering the battery with a full hundred amps.

A loose connector on the voltage regulator was replaced and the issue has been good so far. But I installed a gauge to see where the voltage is at. just incase it happens again. The smell of cooking battery is bad and offensive not to mention, well, too late!

Now I cruise around at 15 volts. Is this anygood?

Part of the inquiry is the inabilty to drive above 55. (LOL, this sucks!)
Hence a fuel delivery thought.
 
You should not be "going through" voltage regulators. It may be that the field in the alternator is partially shorted and drawing too much current in the field circuit. Of course in today's world, "Chinese" parts can be ungood

Make sure the regulator is grounded to the battery. Check this by:

With the engine running at fast idle, stick a meter probe RIGHT ON the regulator case, the other probe RIGHT ON the battery neg. post. You should read very little, the less the better. Anything more than .2V (two tenths of a volt) means you don't have a good ground in that path.

Do the same, hot side of circuit. Stick a probe right on the bat. positive post, the other probe right on (close to the reg. as you can get) to the ignition supply. Once again, the less voltage the better, zero is perfect, and more than .2v is too much.

If you have a high reading here, it indicates poor connection from the regulator--ignition feed--through the bulkhead--to the ignition switch connector--or the switch itself, or maybe out through the other side of the switch and back through the bulkhead to the battery.

It is also possible that you have boiled the battery enough that you just plain ruined it.

Cheapest way to check, if you have a couple of vehicles, is to temporarily swap batteries with a known good one and see "if the problem moves."

15 Volts is "getting high." It may be that you are getting LOW IGNITION voltage to the regulator and ignition system, as the tests above should show. In other words a bad connection from the switch may be giving the ignition and the regulator both low voltage compared to the battery, and this will cause the VR to run high.

Some VR's are wrong, too of course.
 
My Duster stays about 15v most anything off idle. It has been this way all summer and
so far has not been an issue.
 
Years ago a friend had a similar issue with his 68 chevy. Repeating electrical issues. Replacing alt', reg', or both. First thing I noticed was electric tape on battery ground cable at the block. A slight tug and the wire pulled right out of the terminal. New ground cable cured it.
 
67Dart273, thenks. Um, OK, since re-grounding the voltage regulator, the volts are 15 constantly.
I'm going to replace the battery ASAP. I was thinking this would be an issue since iot has been beat up a few times by a super overcharging.
 
Oh, and yes, I'll be going over grounds to be sure. This problem came out of no where. I've had the car 8 years without issue. So it has been a surprise to me and in an area I'm not to good with.
 
Factory 1979 service manual reads:

Ambient temp. near voltage regulator / Voltage range

-20deg. F 14.9v-15.9v
80deg. F 13.9v-14.6v
140deg. F 13.3v-13.9v
above 140 deg.F less than 13.6v

For the 100 amp. alternator, bench testing of the field coil current draw is as follows: isolate the alternator on wood or rubber, connect one field terminal to a fully charged battery, connect one ammeter lead to the other field terminal and the other ammeter lead to the other battery post. Slowly rotate the alternator by hand and you should get 4.75 Amp. to 6 Amp draw @ 12 volts.
 
I am doing the same thing with the duster I just purchased.
Start it up and you can watch the voltage climb, I seen it as high as 15.8 volts.
The ECM when I bought the car had already had the epoxy on the back running out of it and down the inner finder.
It ran long enough to get it on the trailer and back off before the ignighter in the distributor took a crap.
Changed the voltage regulater and no change.
I bought a one wire alternator but have not have time to install.

My dad had the same problem on this 78 truck about 10 years ago, and it wiped the amp gauge out, which everybody knows kills all the electric to everything.
 
NBDarts, so generaly speaking, I shouldn't really be seing more than 14.6 volts then?
 
rumblefish360 said:
NBDarts, so generaly speaking, I shouldn't really be seing more than 14.6 volts then?
Click to expand...

In reality 13.8 to 14.2 is really what you should have. Factory ammeter? Have you checked voltage at the regulator? My book shows a dark blue and a dark green plugged into the regulator.

When the car is sitting there running at idle:
What is battery voltage?
What is the voltage at the dark blue wire at the regulator?
What is the voltage at the output of the alt.?

You should get the same voltage at the battery as you are seeing on the dark blue wire on the regulator, maybe .4 volts less at the regulator.

Was it a factory 100 amp. alternator? it might have been because of rear defroster and A/C.
 
rumblefish, I would suspect a weak battery. As the battery gets weaker, it will require more current from the charging system. Since you said it was gettin "hammered" with a full 100 amps, that's a ton. they can't take all that for long.
 
StrokerScamp said:
rumblefish, I would suspect a weak battery. As the battery gets weaker, it will require more current from the charging system. Since you said it was gettin "hammered" with a full 100 amps, that's a ton. they can't take all that for long.
Click to expand...

Very good point!
 
Hey guys. I was about to go and get a battery since I was thinking the same thing about it being hammered real well over and over again. At cruise and such, it's nearly dead on 15 volts. In neutral, it comes down a bit, but only after it has been running awhile. Like the battery is slow on taking a charge back into it.

I'd tell ya the voltage on the wires, but as my luck has it...or lack there of, my meter just busted. Along with most of my other stuff. (Electrical tool wise) This is getting annnnouying in a big way. LOL, It's like all my stuff is dropping dead at the same time. I'll have to rummage through some papers first before I leap at the battery. Shouldn't be a problem. (I hope! LOL!)
 
RedFish said:
Years ago a friend had a similar issue with his 68 chevy. Repeating electrical issues. Replacing alt', reg', or both. First thing I noticed was electric tape on battery ground cable at the block. A slight tug and the wire pulled right out of the terminal. New ground cable cured it.
Click to expand...


Lol,it's standard practice for me rthat WHENEVER I have odd electric problems I replace the ground cable right away. I had an 88 ?Caravan that stalled on right hand turns,did lots of funky electrical stuff. New ground cable and it all went away. Same again more recently with my GMC truck. Signals going haywire,rough idle etc etc.replaced the ground cable,all problems except the rough idle are gone. Rough idle is probably plugs.
 
And a new battery is in, group 27, what should be there...and the voltage at cruise went up a 1/2 to 1 volt at all times no matter what I'm doing or running. 15-1/2 - 16 volts.

Weird........

However, now I find out I do not have a horn, so I put in a fuse, get a horn, loose power windows. Use'em once and the horn goes out along with windows.

Replace fuse in windows, fine, replace fuse into horn...pop, OK, no horn but have windows. I'm OK with that for now, I can stay warm/dry and they watch for finger....

This car is a FUBAR of wires, nothing new for MoPars or these years, I was starting to think a painless wiring system to get around all cave eats. IDK. (Bummmmmmmed, but driving)
 
I would wait a few days before you make a judgement. A lot of times, them batteries sit on the shelf at the store and get discharged to some degree. When you put um in, the chargin system will put out a good bit until it gets the battery fully charged again. How much have you driven it with the new battery?
 
Was it a factory 100 amp. alternator? it might have been because of rear defroster and A/C.
Click to expand...
Factory 100 amp Alt.
Rear defroster not on yet, or actually before the problem, works OK now. (Sort of, all 4 rows of element.)
A/C disconnected. Electricaly and mechanicaly.
OH, almost forgot. Amp meter dead. Been dead, allways dead.
Own car 8 years.

Only about 15 miles or so., 20 min.s. or so.
 
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