Charging issue '70 Swinger

[Robj]

I'll try to give as much detail as I can. Charging systems have always been my weakness.

1970 Swinger 318 with a two field alternator. My dash ammeter started dropping to discharge always at idle. Approaching a turn, my turn signal would make the needle wave back and forth between charge and discharge. If I turned the lights on while driving it would drop to the center line. I checked the voltage at the battery and at idle it was about 11.5 volts and at higher RPMs it was just over 12.

I replaced the alternator which to be honest looks like the original old style alternator with a 1969 date stamp on it so I’m guessing maybe it had been rebuilt and repaired previously as opposed to being replaced. I replaced it with a 60 amp alternator from NAPA and also installed a new NAPA voltage regulator. I put a new end on one of the field wires which had some frayed strands. The odd thing is that since owning the car I could never figure out what this shiny goo was dripping down the firewall. It turns out the resin or whatever it is filling the backside of the old regulator was melting and dripping. Anybody ever seen that before? Maybe typical but it’s the first for me or is this a sign of other problems. See photo.

Now that I’ve replaced those two components, the ammeter sits just a hair above the centerline at idle and moves up to the first charge line at any higher RPMs. It lowers about a needle’s width towards center when the headlights are on. And flutters into discharge at idle with the headlights on and a turn signal on. As long as I’m above idle it’s always up near that first charge line. See photo.

I checked the voltage of the battery and it was 12.68. At idle it dropped to 12.62. I ran up the RPMs and it jumped to 13.02 and then did a digit-by-digit slow creep up to 14. Headlights on and it slowly dropped to 12.83 at higher RPMs and 12.57 at idle.

After that idle was 13.31 with the headlights off.

I swapped to a second regulator from my son’s project car and it replicated the first results.

Is this a bad new alternator? Bad battery? Maybe grounds? Bad dash ammeter? What should I be testing here? Am I about to fry some wiring or the battery with the apparent constant state of charge or is this just the quirkiness of a 1970 charging system?

Thanks.

 

[67Dart273]

This is NOT normal, but it's difficult to imagine just what might be wrong.

You MIGHT have serious issues with the 'ol bulkhead connector, OR you might have an alternator that is not capable of putting out enough amperage,

Here's how I see some of the possibilities, and you might have multiple problems

FIRST how did you measure this voltage at the battery? It SOUNDS like you measured it with engine running? If so, it should be charging much closer to 14 RUNNING with the battery "normalized" and all loads (lights, heater, etc) off

Possibilities:

Might even be a battery problem

Resistance in the charging path from the alternator to the battery. This goes through the BULKHEAD CONNECTOR and is the no1 suspect. Read this:

http://www.madelectrical.com/electricaltech/amp-gauges.shtml

and note their simplified diagram. It outlines just how this circuit is put together.

Might be resistance in the field circuit not allowing the alternator to develop full output when needed, OR might just be a defective alternator Just one example might be a couple of bad diodes which can turn a 60A alternator into less than a 20A alternator.

In your case, this seems so screwed up, read through your shop manual in the electrics section concerning testing the alternator. If you don't have one, download one here:

http://www.forabodiesonly.com/mopar/showthread.php?t=132309&highlight=manual,+download

IN your case the 72 manual is as good as any for this purpose.

Some things to check:

Check the voltage drop in the circuit path from the battery--fuse link--bulkhead connector--ignition switch connector--through the switch--back out the switch connector--back out the bulkhead--to the alternator field.

TO DO THIS, turn the key to "run", engine OFF. Get a probe or clip lead so that you can probe the BLUE wire (not the green) at the alternator field. Put one meter probe directly on the battery positive post, and the other on the blue wire on the alternator, and you are measuring "voltage drop" so you are hoping for a very low reading. Zero would be perfect, you hope to see NOT OVER .2-.3V, that's three TENTHS of a volt. Anything over about 1/2volt means you have a poor connection somewhere.

IF that checks out, start the car, all loads off (lights, heater, radio, off) and run at an RPM to simulate "low cruise" (fast idle cam is OK) until the battery "normalizes" IE ammeter CENTERED.

IF it just won't do that, ignore, and check the battery after starting and running for 5 minutes. You would LIKE to see very close to 14V. Turn on the headlights, heater, and recheck. IF this voltage drops dramatically at the battery, move the meter probe over to the alternator output stud and recheck, loads on, loads off.

This voltage should NOT be much higher than battery voltage. If it is, this shows that you have a bad connection in the circuit path from the alternator to the battery. Refer to the Mad Electrical diagram at the link I posted to see how this works.

If the voltage between the battery and alternator output stud are NOT quite different, IE about a volt, maybe 2, then you MAY have an alternator that is not capable of enough output.

To "quick check" this, use clip leads, and disconnect the alternator field connections. Clip one of the two field connectors on the alternator to GROUND, and clip the other to the battery.

Start the engine, and carefully bring up the RPM. The battery voltage should start to climb, up over 14, but do NOT let it get over 15--15.5. You can turn on lights heater, and bring up RPM again, slowly, and recheck. Once again, you should be able to get the voltage up over 14.

IF NOT, recheck the difference in voltage between the battery and the output stud of the alternator. IF these two voltages are within say, 2 volts or less, then you have some problem in the alternator.

This nonsense of dripping resin from electronic boxes has been with us for some time now. GENERALLY it either means the box has some problem, or that it's a cheap Chineseo copy that simply is not as good as OEM.

Once again---you may have multiple problems here. You may find yourself seeking shop help.

 

[Robj]

That's great information. Thanks. I have dealt with the bulkhead connector problem with my 74 Satellite I just gave to my son. We ended up running the wires through their own grommets and took care of it.

I've spent the evening reading up on alternators and voltage regulators and what you're saying is making sense to me now. I have a 71 factory manual and the wiring diagrams seem to match so far.

If I get to the test of connecting the jumpers to the field connectors, does it make any difference which goes to the ground and which to the battery? In this test the regulator is being bypassed which is why the max voltage has to be so carefully watched I assume?

This gives me some really good places to start. I actually had a brand new alternator for my wife's car have a bad diode right out of the box some years ago. Thanks again.

 

[RedFish]

I like to start with basic inspection and cleaning connections. The fusible link at the firewall has a service disconnect that will corode or melt. The battery terminal connections at the engine block, starter relay, etc.. are all suspect. Sometimes the factories molded rubber terminals look OK but a ohms meter will prove otherwise.
Good hunting

 

[wjajr]

Aside from all the locations for voltage drop redfish mentioned, the battery is the third component in the charging circuit triad.

Don’t rule out a defective or degraded battery. Old age and off speck charging levels can damage the batterie’s ability to hold and or accept a charge. When battery is in this condition, charge level will be high. Take the battery somewhere and have it load tested.

 

[67Dart273]

I was thinking more about this. Bear in mind, I am not accusing the OP of mis-describing the problem, BUT what he described is contradictory

High ammeter readings indicate OVER charging, yet the battery voltage seems low

First thing I'd do is check the battery

Second thing is look--has the wiring in the car been chopped up? Are there some big heavy, or re-wired loads that have been added to the car?

 

[Bulldozer]

my duster has a new battery, alternator and voltage regulator. it shows a light discharge in gear but shows a charge while rpms are up and the gauge also fluctuates when the signals are being used. for my car, it is normal.my battery has never gone dead and the system is charging when i pull the + side cable off the battery.i have relays for my HID headlights and they never go dim or show a voltage drop beyond my "normal" discharge reading even in gear. those older gauges are very sensitive to voltage and the slightest fluctuation in voltage will usually register.it cranks right over even on the coldest of mornings.my gauge never shows a "centerline" charge reading.it is always moving.i have never had a problem with it. i have been running the same charging parts for the last two years. i dont know if this is even relative to your problem but there arent very many parts that can cause a draw in your charging system in these old cars outside of a short circuit somewhere. but as stated, you could have gotten a defective part, it happens a lot.if you have another old mopar that charges correctly. it is easy to weed out the most obvious parts first ie; alt,battery,VR. BAD GROUNDS have been a huge part of the problems i have had. i have had bad starter solenoids draw a current off of the charger system as well. just a thought.....

 

[wjajr]

73AdodEE,

my battery has never gone dead and the system is charging when i pull the + side cable off the battery

Gezzz, never disconnect battery with engine running, this action will kill diodes.

or show a voltage drop beyond my "normal" discharge reading even in gear. those older gauges are very sensitive to voltage and the slightest fluctuation in voltage will usually register

Unless you replaced Amp Gage with Volt meter, the stock gage is showing current or amps, passing through the bulkhead connector, and which way current is flowing in relation to battery charge level, and alternator output.

there arent very many parts that can cause a draw in your charging system in these old cars outside of a short circuit somewhere

Current draw is relative, if you have a 36 amp alternator, headlight, heater fan, and recent starting of engine can be a lot draw. With a 60 amp alternator, upgrade sound system, headlights, heater fan, and electric radiator fan will be a big load at idle. The reason your relay powered headlights don’t move the amp gage is because the current flowing from alternator is bypassing the gage going directly to lighting load.

By the way, using relays to operate lighting loads, electric choke, engine cooling fans, and convertible top motor is about the best wiring up grade one can do on an old Mopar. Good job there 73.

Oh one more housekeeping thing. Please help us half blind old farts out a little by using caps to start sentences, and spacing between paragraphs for easer reading and understanding of your thoughts.

 

[67Dart273]

....................... never disconnect battery with engine running, this action will kill.......................

X10. I WISH I could put this wives tale to bed. THIS NEVER WAS a legitimate test, and you will never see this "test" taught in any automotive school, or in any textbook, shop, or motors manual, or even Haynes or Chilton, for that matter. The newer the car is, and the more electronic components in the car, the greater chance for a failure.

AND it PROVES NOTHING.

A If the engine happens to be idleing SLOW enough that the system won't charge, you might mistakenly believe you have a problem

B If the alternator has some damage, IE bad stator or diodes, you might have a "10A" alternator instead of a 30, 40, or 60A alternator. So it MIGHT just generate enough juice to operate the engine and you might mistakenly believe you do NOT have a problem

using relays to operate lighting loads, .

THIS IS ONE situation that actually might contribute to a problem with these symptoms. IF YOU USE relays for several things, such as lights, and the ignition/ regulator circuit, AND if you still have the factory ammeter, the AMMETER WILL NO LONGER READ CORRECTLY, and furthermore, when you have the "relay loads" turned on, (might add fans, stereo) this will cause the ammeter to FALSELY read upscale and lead you to believe it is charging when in fact it MIGHT be centered or even dis-charging.

 

[Bulldozer]

73AdodEE,


Gezzz, never disconnect battery with engine running, this action will kill diodes.



Unless you replaced Amp Gage with Volt meter, the stock gage is showing current or amps, passing through the bulkhead connector, and which way current is flowing in relation to battery charge level, and alternator output.



Current draw is relative, if you have a 36 amp alternator, headlight, heater fan, and recent starting of engine can be a lot draw. With a 60 amp alternator, upgrade sound system, headlights, heater fan, and electric radiator fan will be a big load at idle. The reason your relay powered headlights don’t move the amp gage is because the current flowing from alternator is bypassing the gage going directly to lighting load.

By the way, using relays to operate lighting loads, electric choke, engine cooling fans, and convertible top motor is about the best wiring up grade one can do on an old Mopar. Good job there 73.

Oh one more housekeeping thing. Please help us half blind old farts out a little by using caps to start sentences, and spacing between paragraphs for easer reading and understanding of your thoughts.

LOL Sorry about the caps. When i said "draw" , I was only referring to a significant draw that would register a complete discharge, and not normal operation. I still have my factory amp gauge. I am an old fart and I get lazy shifting to caps on my keyboard. We have always tested alternators in OLDER cars by simply making sure it was charging by pulling the + side battery cable without any ill-effects. I would never tell any one to do this, only sharing what works for me. I only used the relays for the HID as per instructions and i dont use them for any other application. I was only sharing what works in my car. People start throwing meters and testers on everything and if they dont have an exact reading, they start freaking out thinking that they have a screwed up system when actually it is ok. Like the guy at checker that throws your brand new battery on a tester and it is showing 12.4 volts at idle, and then tells you the battery is no good because it should be showing 13.6 without checking anything else. ops:

 

[oldkimmer]

..............A lota years ago i had the same problem, went to ma mopar, problem solved............thats y u pay 4 the factory oem regulator........but i have seen where its the battery thst was the problem.....kim........

 

[Robj]

"Check the voltage drop in the circuit path from the battery--fuse link--bulkhead connector--ignition switch connector--through the switch--back out the switch connector--back out the bulkhead--to the alternator field.

TO DO THIS, turn the key to "run", engine OFF. Get a probe or clip lead so that you can probe the BLUE wire (not the green) at the alternator field. Put one meter probe directly on the battery positive post, and the other on the blue wire on the alternator, and you are measuring "voltage drop" so you are hoping for a very low reading. Zero would be perfect, you hope to see NOT OVER .2-.3V, that's three TENTHS of a volt. Anything over about 1/2volt means you have a poor connection somewhere." I'm getting 1.57...I'm guessing that's bad...


"...check the battery after starting and running for 5 minutes. You would LIKE to see very close to 14V." 15.5



"Turn on the headlights, heater, and recheck." 14.86



"IF this voltage drops dramatically at the battery," move the meter probe over to the alternator output stud and recheck, loads on, loads off." 15.75 load on load off

I've tried two voltage regulators with the same results. I'm feeling like it's not getting the correct message to control the voltage. I assume this is attributed the voltage drop I tested first?

Start cleaning and checking connections throughout the entire loop in through the bulkhead connector and back out again and everything in between?

 

[67Dart273]

It appears that you have two separate failures, both of which are contributing

No1 problem is the voltage drop in the harness. You have GOT to find that, and as I said, your no 1 suspect is damage in the bulkhead connector. Pull it apart, inspect, clean, replace connections, or spice in bypass wires and just thread them through the holes

Another thing you can do so far as the ignition/ regulator drop is to install a relay out on the firewall to operate the ignition / regulator. You can buy "Bosch style" relays with a mounting hole, run a fuse from the starter relay stud to the relay, and use the relay to "fire" the ignition and regulator.

Second, you DO have a lot of drop on the charging lead. For NOW I would consider doing a temporary (or permanent) bypass of that circuit. Read the MAD article:

http://www.madelectrical.com/electricaltech/amp-gauges.shtml

from here:

http://www.madelectrical.com/electrical-tech.shtml

and basically, run a nice big, say, no8 wire from your alternator stud directly over to the stud on the starter relay

But you STILL need to examine the bulkhead connector, clean and fix it.

I'd bet these two things will go along way towards getting you down the road.

 

[Robj]

I replaced the blue and green field wires and connectors under the hood. I noticed there was no grounding strap from the engine to the body so I put one on.

I pulled the engine compartment plugs from the bulkhead connector and everything was super clean and looked good. No signs at all of corrosion, burning or melting or heat of any kind. In the passenger compartment everything is very clean. I didn't mess with the ammeter ring connectors. They are shiny and bright and look like they were installed yesterday. If it ain't broke....I did fabricate a bypass to run under the hood between the battery terminals on the alternator and the starter relay. I tried it out and it works great but took it off for now so I can observe and compare the ammeter's behavior from before and currently.

When I start it up the needle moves just to the right of the center line on the gauge. After running for a few minutes it comes back to center and sits within the white line just barely a hair to the right dead center. When I turn my lights on the needle flickers for fraction of a second and returns to the original position. It no longer makes a big wide swing.

The voltage at the battery when running is 14.9 on my meter- regardless of idle speed- lights on/off.