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Discussion Starter · #1 ·
I’m trying to get my truck to where I can take it wheeling just once before this summer ends. I thought I had it running okay until recently. There are a few things that I think are related but I can’t be sure.

The first problem exposed itself while driving one day. If I tried to get in the gas too hard, it would hesitate/misfire pretty severely.  I thought it was a fuel issue, so it sat a couple days and then I took to it to fill up. It started up, although a little slow. On the way to the gas station, the hesitation was still there. I get there, fill up, go to restart, and it just clicks. I get a jump, starts right up, throw it into gear and it dies. Jump again, I idle it and rev it a little, and doesn’t die in gear this time, although I had to baby it in the way home.  Testing with a meter, battery and alternator show low voltage. I had another alternator sitting around, so I throw it on. If I remember right, the alternator showed around 16 volts when grounded in the case and the battery around 14-14.5 or so. At this point, my ammeter was pegged at the “C” and the wiring started smoking but I chalked it up to old wires and common ammeter problems. Over time, it seems the alternator and battery have been showing less voltage than it did right when I swapped it out.

Are both alternators bad, or maybe a bad regulator or wiring? Battery is only a few months old, but I had used it to crank a lot in the process of getting the truck together. That and running with it not really charging may have killed it already.

My other thought was possibly timing or carb tuning. I had initially timed it around 12* BTDC but wasn’t ever sure it was correct. Digging into it more, I found my vacuum gauge, and checking the full vacuum port on my edelbrock 1906 was around 22 inches of  steady vacuum. I backed it off to about 20 and called it good. I forgot to double check timing with my light, but I think I ended up about 10* or so. I also tried tuning the idle mixture screws but I’m not confident in what I did there all. After the timing and carb adjustment, it died on me 3 days in less than an hour of run time.

Again, I have no real idea these are related and I’m not 100% sure in how I tuned the carb. The truck just seemed low on power but may require more than just idle mixture screw adjustments.
 

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It is likely your starting and running problems are related to low operating voltage from a charging system failure. When voltage gets low enough,there's not enough juice to run ecm and ignition coil and why truck shut off. Surprised you were able to drive it home.

How long did you have the alternator full fielded(grounded) and what wires were smoking?
It's possible you discovered the problem or may have caused more problems by leaving alternator full fielded for too long. The full field test you did was supposed to be done with a voltmeter hooked to battery and have field grounded no more than a couple seconds.

Start by removing battery and have it charged and tested. Need to put eyes on wire harnesses underhood and behind dash for melting and damage. Pull the dash and inspect wiring coming to and from ammeter.

  Remove the bulkhead connector in engine compartment and inspect terminals on both sides for overheating/burning.
Trace out alternator output wire from alternator back around to battery for overheating and/or corrosion.

You'll need a fsm to trace and understand wire diagrams. Dodgeboys on this site may be able to help you with that. Unless you/re lucky and good,it's going to take more than a few days to diagnose and repair your truck,but it can be fixed.

Until you are able to start working on the truck it would be a good idea to disconnect the battery. When wiring gets hot enough to smoke,insulation can be melted between wires fusing circuits together that were never meant to be. Weird things can happen,disconnect battery while truck is sitting. Good luck with repairs.
Post back with questions you have.
 

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Discussion Starter · #3 ·
modelcitizen said:
It is likely your starting and running problems are related to low operating voltage from a charging system failure.

How long did you have the alternator full fielded(grounded) and what wires were smoking?

Start by removing battery and have it charged and tested. Need to put eyes on wire harnesses underhood and behind dash for melting and damage. Pull the dash and inspect wiring coming to and from ammeter.
I wouldn't be surprised if it did come from a charging system failure. I just wasn't sure there was enough correlation or other issue considering this is a fairly new carb.

What exactly do you mean full fielded/grounded? When I checked the output on the alternator, I had the positive end of my multimeter on the stud and the negative on the alternator case itself. The charging wire was on the stud, and both field wires were connected. The only smoke I saw was coming from inside the dash. I already had the bezel removed so it was fairly easy to see were it was coming from. After running for a little bit after the initial alternator change, and any time after that, it hasn't smoked anymore. I had looked in the engine compartment when it started smoking, and hadn't noticed anything even getting hot.

I'll pull the battery out today and get it charged and tested. I'll look further into the wiring and see if I can identify anything else. So far I've just blamed it on the common poor contacts in the ammeter.
 

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Your statement"the alternator showed around 16 volts when grounded in the case" tells me the alternator is overcharging whether thru a fault in the voltage regulator or its associated wiring.
The only other way for the alternator to charge 16 volts is when one leg of field in alternator is grounded for a few seconds. It is a go/no go test to see if the alternator is bad or the voltage regulator might be the cause of a no charge condition.
Your statement and what i just wrote are pretty similar,no?

Reading what you just wrote about how you tested alternator output voltage,clears that up. So your overcharge-at that time-would be caused by defective voltage regulator or problems from the field wires from alternator and back to the regulator or an under voltage condition from the wire that supplies voltage to the regulator.

The voltage regulator uses this input voltage that should [email protected]= to battery voltage to determine how much field voltage is needed to increase alternator output to charge battery back to regulator set voltage.
A regulated alternator should never put out more than 14.5 volts,that's one identified problem.

The smoking in the dash that you now say you knew? about is another. Where exactly is it smoking. For what it's worth,whenever  a circuit-any circuit or connection is hot enough to smoke,it is now damaged. Because it is not smoking anymore doesn't mean it's ok or "fixed".
The reason it's not smoking anymore could be one reason why your truck is not charging anymore.
What wires/connections were smoking? Pics?

I'll wait til you post an answer to that.

You will need to fault trace the regulator wiring for shorts to ground or to each other and repair whatever is found-if anything.The sense wire coming to voltage regulator needs to be sorted out.
Next you will need to determine if your alternator is still good and then if the regulator is good.
 

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Discussion Starter · #5 ·
If I understand correctly, full fielding or grounding out the alternator, would make it charge at 16 volts (or whatever the max alternator output is) and is only done for a couple seconds as a test or there is an issue present in the wiring or voltage regulator. This again is similar to what you wrote, but repeating makes it easier for me to be sure I have it correct.

If full fielding/grounding is a test, what is the proper way to go about this?

I never said I thought it was fixed, just that I knew the ammeters were known for developing a poor connection and smoking. Since this is now damaged, will a burnt out ammeter prevent the charging circuit from working completely?

I just started looking at the truck for a couple minutes. Here are a few things I’m checking. I’m not sure all these tests are necessary or relevant but here is what I did.

Battery voltage after sitting for only a day or two and before starting the truck was 12.5 volts. The stud on the alternator with the engine off also reads 12.5 volts. Both of these tests are with key off. Is it normal to have voltage at the stud with the key off?

Next With the key on, the battery shows 12.25 volts. From here I unplugged both field wires from the alternator. One probe in one, the other to ground. The red wire showed 0 volts, the black showed 10.5. I believe from my reading, that one wire should be zero, and the other should mimic the battery voltage? If so, I am obviously a couple volts off.

My next set of tests were with the engine running. I’m not sure how much of a difference it makes, but the truck is not warm and ran only a couple minutes. Just slightly more than enough time to check my voltage. Idling around 800 RPM’s the battery showed anywhere from about 13.5-14.5 volts. The stud on the alternator still shows around 15.5 volts.

I did not do any testing on the regulator.  What is the best method/where should I test to get a good reading?

Pictures will come shortly.

Do any of these numbers give me a solid path to start?
 

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Start the truck again and while idling open throttle with throttle linkage to about 1500 rpm for couple seconds. What happens to battery voltage,how high does voltage at alternator output stud go?

Disconnect connector from regulator,turn key on ground negative test lead and test green-i think it is,wire in  regulator connector,what is voltage reading? Take the voltage regulator off the firewall and look  at back side of it. Post pic.

Take some pics of backside of ammeter and connectors. and post.
 

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Discussion Starter · #7 ·
Ok, with a helper holding the throttle at around 1500, battery voltage was at 15.3 and alternator was about 16.3. I’ve definitely got an overcharge situation going on.

Key on, the green wire on the voltage regulator connector reads 11.3 volts. Right away it did look like there is a little bit of corrosion on that connector.

I do however have a used spare voltage regulator and connector I can test with. I’m not sure what I’m looking for on the voltage regulator but the back was not all completely flat and had what looked like a little hole in it.


The pictures will come later. I am unable to post them from my phone.
 

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What was the battery voltage when you  got 11.3 volts at regulator connector-this is important.

Take a pic of back of regulator. Need to see these pics. Have you tried sending pics to your pc. I have to do this occasionally,i text pics to my email and download them and post them here.
 

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Discussion Starter · #9 ·
I know I tested it but I can't quite remember. I believe it was 12.3 or so.

I usually have to email them to myself as well. Only problem being my truck is stored elsewhere currently and my computer was at home.

I've attached a few of the voltage regulator. It's kind of hard to get a quality pic of the back. You can tell however its not flat (I'm not sure it is supposed to be or not) and that there is a little hole in the bottom left of every picture.

I also attached one of what the back of the cluster looks like. I guess I know for sure where the smoking was coming from. From the outside, the wiring all looked good, only the plastic of the cluster was burnt and black.

There is also two pictures of the ammeter itself. The studs were both loose and look black-ish/like they got hot. Looks like the little mount is broke as well.

On an unrelated note, I'm sure I've just caused myself a nice headache. I broke 3 of the 4 metal clips holding the front of the cluster on, I broke the needle on the speedometer, and the biggest issue is that I broke a few pins off the large connector on the circuit board and they are stuck in the connector itself.

I guess I need to learn to stop myself after I break one thing.
 

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the alt field voltage is about 1/2 of what you want it to charge at .. so about 7 volts . It is controlled by the amount of GROUND supplied by regulator , if/when you apply 12 volts positive to one field wire and GROUND the other side yourself , a good 12 volt alternator will try to make around 24 volts , 16 volts would be a weak alternator .  If its wired as factory and making 16 volts , remove both field wires , turn key on , test with your meter's - on ground find the 1 field wire that has battery volts , put it aside , place your meter's + side on the large post , check for battery voltage .. O.K. ? put meters - side on the other field wire read volts , figger a good alt will doubble that , reading 8 volts? regulator bad , or power INTO regulator from key low .  note your truck has a harness that runs around the motor , a connector ON the pass side valve cover area is KNOWN to be bad ..... loose dirty burnt ....
 

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laxjunkie said:
I know I tested it but I can't quite remember. I believe it was 12.3 or so.

I usually have to email them to myself as well. Only problem being my truck is stored elsewhere currently and my computer was at home.

I've attached a few of the voltage regulator. It's kind of hard to get a quality pic of the back. You can tell however its not flat (I'm not sure it is supposed to be or not) and that there is a little hole in the bottom left of every picture.

I also attached one of what the back of the cluster looks like. I guess I know for sure where the smoking was coming from. From the outside, the wiring all looked good, only the plastic of the cluster was burnt and black.

There is also two pictures of the ammeter itself. The studs were both loose and look black-ish/like they got hot. Looks like the little mount is broke as well.

On an unrelated note, I'm sure I've just caused myself a nice headache. I broke 3 of the 4 metal clips holding the front of the cluster on, I broke the needle on the speedometer, and the biggest issue is that I broke a few pins off the large connector on the circuit board and they are stuck in the connector itself.

I guess I need to learn to stop myself after I break one thing.
Strongly recommend you do the ammeter bypass,what you have found here is a partial answer,possibly the whole problem,to your charging issues and some of your other low voltage complaints.
Take a pic and post here of the two wires/terminals that bolted to ammeter. If they have seen enough heat they may need to be replaced.
I think the best thing you can do is eliminate the terminals cut back each wire @1/4"and crimp each end of ammeter wire into a 10 gauge lug and solder and heat shrink,electrical tape and hockey tape the connection to insure best case insulation. Needs to be a good solder job,this connection basically supplies voltage to everything in truck other than starter.

This is 1st thing i would do. The pics of your regulator look ok,suspect the alternator may be ok too.
You can do this and recheck voltage at regulator connector key on.
It needs to be within @.5 volt of battery voltage for system to charge battery properly.If close to that,reinstall regulator and field wires to alternator and start and run truck and check battery voltage then check voltage at output stud of alternator,it should not be any higher than 14.8 volts.
You don't need your instrument cluster installed to turn key on for voltage checks and start and run truck for testing purposes.

Reinstall ammeter into cluster-to fill the hole. Sorry to hear of breakage problems in instrument cluster,can't say i've never done anything like this. Best answer for this will be to find a used cluster for your generation truck and make one out of two,have done this myself. You should be able to extract broken pins from cluster connector without too much trouble,try not to enlarge sockets while doing so.

You are deleting ammeter function,recommend installing a voltmeter somewhere in truck to monitor condition of battery and electrical system. A voltmeter will give more accurate info than an ammeter.
 

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our trucks that had an actual amp meter , had problems with them burning because ALL electrical functions ( except starter) had to pass thru that meter Dodge switched it to a shunted amp meter , later a simple volt meter . IMO that's all ya really need ... you are diagnosing an non computer truck with a computer  ???  when you read 15.xxxx at the battery and 16.xxx at the alt , there is already a problem , a whole volt went missing between the alt and the battery . I'd get a factory wire diagrame  for YOUR truck . then change to a voltmeter , wiring the alt output TO battery positive , ( where it eventually winds up now ) eliminating all the bad connections along the way ( as seen in you wire diagrams ) with protection in line .  behind the voltage reg ... they pour liquid in right over the components to seal them , flat or not means nothing ....
 

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Discussion Starter · #13 ·
Ok, i was able to grab a couple pictures of the wires that go into the ammeter. They look fine to me, but ill put the pictures up.

I have a few questions.

1. When checking the voltage at the alternator stud, field wire, and voltage regulator, what should i be seeing in relation to the battery? With key on, engine off, battery voltage has been right around 12.25 volts. Should these 3 locations mimic battery voltage?

dodge82273 said:
the alt field voltage is about 1/2 of what you want it to charge at .. so about 7 volts . It is controlled by the amount of GROUND supplied by regulator , if/when you apply 12 volts positive to one field wire and GROUND the other side yourself , a good 12 volt alternator will try to make around 24 volts , 16 volts would be a weak alternator . If its wired as factory and making 16 volts , remove both field wires , turn key on , test with your meter's - on ground find the 1 field wire that has battery volts , put it aside , place your meter's + side on the large post , check for battery voltage .. O.K. ? put meters - side on the other field wire read volts , figger a good alt will doubble that , reading 8 volts? regulator bad , or power INTO regulator from key low . note your truck has a harness that runs around the motor , a connector ON the pass side valve cover area is KNOWN to be bad ..... loose dirty burnt ....
I may have read this wrong the first time about checking the field wires. I'll check them again. Are you saying i should be getting 7 volts at the field wire? Im having a hard time getting my thoughts together. I'll come back to this.

2. Where exactly should my ammeter read at when installed? I know its discharged/charged but should it be off to one side or in the middle?

I threw on the other regulator and connector i had. I'm not sure it made any difference. Alternator read about 15 volts at idle.
 

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Discussion Starter · #14 ·
Ok I brought the truck home, makes it a little easier to get at and it is now covered. (a good thing until I can figure a good way to seal the top back up.) With the other regulator and connector on, I took a couple more readings.

With the key on,
Battery: 12.2 Volts
Alternator (w/- probe to ground, + to stud): 11.84 Volts
Black field wire (- probe to ground, + to field wire): 11.2 Volts
Red field wire (- probe to field wire, + to alternator stud): 12 Volts

I don't think these field wire colors match factory, I already re wired them myself.
 

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When you say stud to field wire, are disconnecting the wire from the alt, or probing into the plug? A better check is the field wire connected, and the other probe to ground.
 

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Right off the top you need to understand the ammeter is compromised. Any tests you are doing with it installed in the circuit are not accurate due to this. Flaw in original design,well documented,there is a sticky thread on the forum on how to deal with this. Reread my last post,i covered the reason. Essentially the "fix"is if the wires and terminals are not heat damaged or burnt to bolt the two together securely using a bolt,locwasher and nut and tape it up securely. The ammeter is now irrelevant,its only function is to fill the hole in dash cluster,this also in my last post. You will need to add a voltmeter to monitor electrical system,it has much more accurate information than the ammeter.
Do you understand the above?

Do this 1st and then check in this order:
Battery voltage key off,now check voltage at alt output stud, it should be identical to battery voltage.

Turn key to run position.Check the voltage at regulator connector green wire. Plug connector into regulator. Now check The voltage at disconnected green field wire  at alternator. It should be identical to regulator connection. This needs to be within.3-.5 volts of battery voltage with the key on.
How did you install the regulator connector into the wire harness?
If you didn't solder the wires together,go back and do so. It is this wire the regulator uses to "sense" state of charge of battery and exactly how much voltage to apply to the field to charge the correct amount of current to bring battery back to or maintain correct battery voltage. There can be no added resistance to this circuit,more resistance=higher voltage charge rate,the 16.3 volts you recorded is proof of excess resistance in this circuit. The 15 volts you recorded on your last test is still high but closer to where it needs to be.
Why don't you go back and do just these tests i described above. Write exact voltage results of each down so you don't get confused and post them here.
A piece of advice from 45Years in the business...don't change more than one part at a time when trying to fix something,you'll never know what actually fixed the problem and if you do this with used parts that may not be known good,you may be building yet another problem into the circuit you're trying to fix,aka chasing your tail.
 

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Just read your last post,you need to be clear about what wires you changed as they are not original colors.Whatever wire the voltage comes to the voltage regulator needs to be within .3-.5 volts of battery voltage with key on. The closer it is to battery voltage,the closer the regulator can control  the charge rate to the battery.
Again if you're not soldering the connections,go back and do so. Twisting wires together and taping or using crimp connectors is not the clean connection this circuit needs. It would be more ok on a bulb socket harness but not here.

Regarding broken off pins in cluster connector,the one pin can be pulled out with pliers,the other two,use a small drill bit and drill into broken connector then screw appropriate sheet metal screw in to connector and use pliers to pull remains of pin out of socket.
 

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Discussion Starter · #18 ·
Ok, I will try to hit everything you guys mentioned.

SuperBurban, when I checked stud to field wire, both field wires were off the alternator. Only the charging wire has been hooked up in all these tests. My probes aren’t small enough to backprobe the connector but I may be able to partially pull it off and probe it.

Modelcitizen, First i do understand about the ammeter. For now, it is currently in place solely to complete the circuit so I could perform these tests. Later this week I will do the bypass to eliminate any inaccuracy caused by the ammeter being in place. I have also ready the sticky about it. The only reason I wondered where it should read, is I was wondering if it had been telling me something and I hadn’t realized it.

My connections had not been soldered. Yes I know I should, but I thought I should see if I had it right in case I had to re do it. I will go back and fix the connections.

The wires I changed were the field wires. I had taped together my own little harness for the alternator/field wires/both voltage regulator wires.

I’ll bolt the ammeter connections together, and solder the wires then re do all the tests and report back when I get the results
 

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I believe you are on the right path,before you had done any repair work your alternator output voltage was 16.3 volts,after this round of repairs it's down to 15.1 volts. That's a substantial improvement. By removing the ammeter and connecting the ammeter wires together and cleaning up and soldering your connections you're removing resistance from this circuit
and very likely you can get that regulator reference voltage"sense" to be very close to key on battery voltage and alternator charge rate voltage down in 14.5-14.8 area and once truck has had a chance to  run long enough and alternator has topped off battery,you should see voltage at battery in 14.0-14.3 range which is perfect.


Regarding ammeter reading,i recall you saying its needle was at full charge. The charging system was charging the max amount it could from the too low voltage present in sense wire for regulator making voltage regulator think battery needed that amount of charging and with the excessive resistance of overheated connections at ammeter that were partly responsible for the undervoltage on sense wire,the high charge rate was being wasted thru heat  at those connections and why you saw the smoke. These trucks have caught fire and burned to the ground from this scenario,you saw the smoke,not much of a jump to go from smoke to fire. Design flaw,the fix is to delete ammeter from circuit.
I'll look for your next round of tests,try switching the original regulator back in after you have your charge rate readings at alternator stud and battery to see if there's any difference.
 

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Discussion Starter · #20 ·
Ok, I’m on to the next round of testing, though all I have done so far is get rid of the ammeter, bolt the wires together, and wrap them in tape. I will still go through and solder wires, but I wanted to see the difference each change made.

Currently voltages with they key off
At battery: 12.44
At alternator: 12.44

Voltages with key on
At battery: 12.2 ish
At alternator: 12.1 ish

Off the bat, these values are much closer than they were.

Key On at the voltage regulator connector and field wires wasn’t much better. Voltage while running was still high as well. Before I do more testing, I’ll go through and solder, and check all the wiring


Another thing I just noticed. I have no idea why I hadn’t checked this before considering this is also a common problem, but I just pulled the bulkhead connector off. Where the black alternator charging wire goes through the firewall, the bulkhead connector on the firewall has obviously been getting hot.
 
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