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Chryco's Tech Shop => Electrical => Topic started by: shadango on November 26, 2009 - 01:42:22 am

Title: 16.4 volts at the battery
Post by: shadango on November 26, 2009 - 01:42:22 am
Noticed that my summit voltage gauge was reading high....almost pegged...so I checked thevoltage at the battery while running.....16.4 or so.  :22yikes:

The alternator, voltage regulator, wiring harness (Bill evans)...pretty much all the underhood electrics...are new, installed last May or so.

The gauge was running high back then too but that detail got lost until now I guess....so I have been running all summer with it overcharging.....no issues to date other than the high reading.... :dunno:

So what can I check, reading wise, to determine the fault?

The VR was checked at autozone a while back when I was having another electrical issue and it checked out fine....what can I check at the alternator to see if its a bad diode?

In another thread ,someone referenced that the Bob Evans wiring harness could be bad....?
Title: Re: 16.4 volts at the battery
Post by: Chryco Psycho on November 26, 2009 - 01:45:42 am
I would just take the alt to a parts store & have it tested , if the wires are in the incorrect position in the bulkhead plug that could be a problem as well you can easily check wire color with a wiring diagram to be sure
Title: Re: 16.4 volts at the battery
Post by: shadango on November 26, 2009 - 01:50:30 am
Holy mackeral that was a fast reply! :2thumbs:

Thanks Chryco.....will check the wiring colors....I have a PDF version of the factory manual.....I think there is a diagram in there.....
Title: Re: 16.4 volts at the battery
Post by: shadango on November 26, 2009 - 01:56:21 am
By the way...the stock ammeter is reading normal, right in the middle.....

Looking at the manual, they show two possible reasons for over charging....either a bad VR or a bad ignition switch...

How could a bad ignition switch cause this?

Mine is new anyways.....LOL

Title: Re: 16.4 volts at the battery
Post by: Chryco Psycho on November 26, 2009 - 02:05:58 am
the ammeter is off center slightly to the C side when running but close to center .
In my experience an over charging is caused by the voltage reg or the alt diodes only                                                                                                     
Title: Re: 16.4 volts at the battery
Post by: shadango on November 26, 2009 - 02:26:45 am
Just checked the wiring colors....

Everything seems to be OK....though the diagram shows the firewall connectors upside down compared to what they are on the car...LOL

The car runs and the gauges etc work fine, so I think you are right.....gotta be an lt or vr issue....

I guess I will pull them both and take a trip down to autozone tomorrow....assuming they are open.

I just had the alt off the other night when I was installing the new heater hose brace..... :banghead:

Could a bad ground on the VR where it mounts to the firewall cause this?
Scratch that....just realized I have a ground strap from the VR to the valvle cover bolt...so ground should be OK.

Whats strange is I ran like this all summer.....shouldnt I have toasted the battery by now???

If I have the green/purple wires at the alternator swapped (both go to the VR) would that cause this?  No, right?  You posted an answer to a similar question here...
http://www.cuda-challenger.com/cc/index.php?topic=43800.0 (http://www.cuda-challenger.com/cc/index.php?topic=43800.0) which is how I wired mine....green wire in the center connector.

Well, I guess that pretty much rules out the obvious stuff......I have the original VR that was in the car when I got it...no idea if it is good or not....may try swapping it in just to see....see any harm in that?



Title: Re: 16.4 volts at the battery
Post by: Aussie Challenger on November 26, 2009 - 05:24:41 am
  The volt gauge could be faulty, reading too high, some of summits stuff is of questionable quality, check with a multimeter to be sure before taking the alternator off again.   :2cents:
  16.4v is a little on the high side and the battery should have shown signs of boiling, lights would have also been very bright.   :22yikes:
Title: Re: 16.4 volts at the battery
Post by: shadango on November 26, 2009 - 08:22:11 am
I did check at the battery already......when running, around 16.4 volts....with engine off, 12.5 or so.....
Title: Re: 16.4 volts at the battery
Post by: 73Chally on November 26, 2009 - 08:24:15 am
If you have 16.4 at the battery, my guess would be the VR.  We just had to replace one in our Super Bee with the exact same problem, except we could smell the battery cooking.  With an ammeter hooked to the battery with the car running, rev the engine and see if the voltage goes up with RPM (alternator spinning faster).
Title: Re: 16.4 volts at the battery
Post by: shadango on November 26, 2009 - 08:36:14 am
You mean hook up a voltmeter, not an ammeter, right?

i believe voltage does increase with engine RPM. the 16.4 volts I measured was at fast idle.....the summit gauge also shows pegged....then drops when RPMs go down some....But will double check.

Should I be checking right at the battery like I am or checking at the ballast resister s the factory manual says ?

Is there a way to test the VR myself? The manual just sys to check voltage and if its high, replace it...LOL
*********update

Just checked the voltage at the ballast resister #1 termninal to the VR ground ......14.5 or so volts.....using the battery ground cable, 14.8 volts........According to the manual, I am just about within range......but then checking voltage at the battery itself, 16.2-16.5 volts..... :clueless:
Title: Re: 16.4 volts at the battery
Post by: 73Chally on November 26, 2009 - 08:53:35 am
I did mean volt meter, oops.  What you are describing is the exact same scenario we had.  If it was me, I would go ahead and buy a new VR to try.  If nothing else, if it turns out to not be the VR, you at least have a spare and you're only out $20 or so.
Title: Re: 16.4 volts at the battery
Post by: shadango on November 26, 2009 - 09:22:40 am
I have an old OEM VR and decided to try that one....it was reading 15.8-15.9 at the battery and just around the same 14.5-14.7 at the ballast.

Put the other back in and now its reading 15.8 like the old OEM one....down from 16.4.

Ok, now I am stumped. 

I guess both VRs could be bad though.....

Also, looks like voltage is NOT going up/down with the engine speed afterall....hangs fairly steady.
Title: Re: 16.4 volts at the battery
Post by: GoodysGotaCuda on November 26, 2009 - 10:43:56 am
Check the voltage at the voltage regulator. If it is getting a low reading such as 12 when its actually 16, it will try to kick the alternator up while running. May have to back probe or stick the wire at some point to do it though. Not too easy.
Title: Re: 16.4 volts at the battery
Post by: shadango on November 26, 2009 - 11:02:32 am
Through which wire?  The blue (purple) or the green?

According to the schematic both go to the fields of the alternator.

Could I just check voltage at one of the field connectors on the alternator?

How can it be reading 12 if its actually 16?
Title: Re: 16.4 volts at the battery
Post by: Chryco Psycho on November 26, 2009 - 12:10:25 pm
the blue wire is the 12v feed , the green is the regulated wire
Title: Re: 16.4 volts at the battery
Post by: quagmire on November 26, 2009 - 12:39:59 pm
At the regulator, you want to check voltage at the blue wire. 

This is the wire that the voltage regulator uses to both turn on and sense how much voltage is actually in the system.  The voltage regulator controls alternator output by controlling the ground (green wire) to the field windings since it has constant power when the key is on.  If the voltage is too low, the voltage regulator will duty cycle more ground to the alternator field windings.  If too high, it backs down.

So you can see now that if their is high resistance or a bad connection in that blue wire at the regulator it will see less than the real system voltage and command the alternator to work harder, thus making your voltage go through the roof.

Make sure the system voltage matches the blue wire voltage, then make sure the green wire is not shorted to ground.  That will also cause the alternator to work at max output. 

A quick test would be to disconnect the two field winding wires at the alternator.  If the alternator shuts off and voltage drops back down to 12 or so, you know it is a wiring or regulator problem.  If it stays pegged the alternator is shorted internally and faulty.
Title: Re: 16.4 volts at the battery
Post by: shadango on November 26, 2009 - 01:12:45 pm
quagmire...

I did the last test you suggested....unplgged the two field wires.

The battery voltage went down to 12.2 to 12.4 or so.....

The wiring is new...a Bill Evans harness.....I dont think that would be it....

SO I guess I will try another VR.

Cant get one today.....everyone is closed...go figure...LOL

Just for kicks I reversed the two field wires at the alt......no chamnge...aboyrt 15.6 to 15.9 volts running.
Title: Re: 16.4 volts at the battery
Post by: quagmire on November 26, 2009 - 02:02:52 pm
Reversing the two field wires at the alternator won't do anything, they are not polarity sensitive.  As long as one is 12v key on and the other is a regulated ground it doesn't care where they are hooked up.


It sounds like the alternator is ok then if it shut off when disconnected.  You may want to just disconnect the GREEN wire and see if the voltage drops.  If it does the alternator is definitely ok.  If not it is shorted internally to ground.

Just because the harness is new doesnt mean you couldn't have a bad crimp on a terminal end or a chafed wire.  It only takes a few seconds to check voltage at that blue wire and ohm check the green wire.  This is just about as basic of a system as they come, with a meter you should be able to diagnose this in a few minutes.
Title: Re: 16.4 volts at the battery
Post by: shadango on November 26, 2009 - 07:35:51 pm
Disconnected the green wire only and the result was the same...just 12.5 or so volts at the battery.

The green wires continuity between the alt and the VR is good.....1 or .2 ohms resistance at the most.....hard to tell....my meters dont want to zero out but pretty sure its between 0 and .2 ohms at the most.

Disconnected the plug from the VR and the blue wire reads only 10.8 volts.  SO it sounds like that is my issue, eh?

The blue wire is actually purple....same color purple as the purple wire at one of the alternator field wires. Coincidentally, the same exact color as the two wires that go to a plug that feeds the carb electric choke.....two wires together going into the same plug.....I disconnected that plug from the choke and no real change....a temporary .5 volt drop or spike when I remove or plug it in....voltage at that plug is 14.8 or so volts.

The only way to see what is going on with the purple wire feeding the VR would be to completely remove the wiring harness from the car and unwrap it and see what is going on.... :pullinghair:

I dont think this matters but I will mention it.....the wiring harness is setup with the plugs for the 4 prong ballast.....a while back I found that one connector (the blue wire at the #1 terminal) was shaky so I pulled it out of the plastic molded plug itself and plugged it into the ballast....leaving the other connector off (the jumper to the other ballast termional on the same side which feeds the green/red wire)...I had read the green/read wire is un-needed with my ECU so I have left it off.....
Title: Re: 16.4 volts at the battery
Post by: quagmire on November 26, 2009 - 07:48:31 pm
Bingo, sounds like you found the reason it is overcharging.  That makes perfect sense then, you are losing about 2v somewhere to the VR, and you are overcharging by about 2v. 

That purple wire branches off and powers several components: choke heater, VR, alt. field winding, ignition ECU, and the ballast resistor.  You will need to find out where in the harness you are losing voltage by tracing back through it and measuring voltage at those components.  If they are all reading low voltage, you probably have a problem at the bulkhead connector or ignition switch.
Title: Re: 16.4 volts at the battery
Post by: shadango on November 26, 2009 - 07:53:26 pm
I am reading 14.5-14.8 at the ballast...so that should rule out the igntion switch and bulkhead then?
Title: Re: 16.4 volts at the battery
Post by: quagmire on November 26, 2009 - 07:59:32 pm
Yup, you will want to start by piercing the wire with a pin right before it goes into the VR connector and measure the voltage, you may just have a bad connector. 

If not you will need to find where the wire to the VR splices off of that main purple wire.  It should be pretty close to where it branches of the main harness.  You can either probe into the wire until you find the spot wher it jumps back up to 12v or just replace that wire and be done with it.

Basically just work your way down from connector to the splice until you get 12v back, lucky for you it should only be within a foot or so of wire and not over the length of the vehicle.
Title: Re: 16.4 volts at the battery
Post by: shadango on November 26, 2009 - 08:05:35 pm
Ok, cool...will try that tomorrow....the wife is yelling at me that I am stinking up the house with fumes....LOL

Have never tried the "pin" method...what, just stick a stick pin or needle into the wire itself and use that to connect to the meter I guess?

I guess the part I also dont understand is that if the purple wire is connected to the field of the alt, how does it also provide voltage at the VR, choke etc?  Would there be voltage at the alt end of the purple wire too then?
Title: Re: 16.4 volts at the battery
Post by: quagmire on November 26, 2009 - 08:15:30 pm
Yes, you are just using a pin to pierce the insulation as little as possible to take a reading. 

When you said you have 14v at the ballast, is that running?

If it is then you probably do have a problem at the bulkhead or ignition switch since the battery voltage is 16v and all of those components on that circuit are 2v lower. 

If it reads that with the engine off, key on ( it could if the battery is being overcharged) then start at the VR wire like I said in the last post.

The field windings need power and ground to operate like any other circuit.  The purple wire gives it a constant 12v when the key is on.  The VR actually supplies the ground to it.  It controls voltage by pulsing the ground  on and off many times a second to maintain 13.5 to 14.5v.  In order to power up and know what the system voltage is, the VR requires that purple wire connection.

That purple wire branches off to power all of those components I listed above, so you should have power at every one of those ends.
Title: Re: 16.4 volts at the battery
Post by: shadango on November 27, 2009 - 02:50:56 am
Yeah, that  14.8 v ballast, 16 volt battery, 14.8 volt choke, and 10.8 volt VR purple wire reading is while running the engine.....

With the engine off, key on - the battery voltage reads 12.4......the voltage at the purple wire at the alt is 10.8, at the choke its 10.8 , at the vR its 10.8 and at the ballast its 10.8.....there is NOT the same 4 volt drop at the purple VR wire that I have when its running....

So doesnt that rule out there being an issue with that VR leg of the purple wire?

Doesn't the ignition switch power ALL of the purple wire at once? What would cause the voltage to be lower only at the VR purple wire when running but not when the key is on but not running ? If it were the switch or bulkhead, wouldnt the drop be the same on all the purple wires?

And also what i don't get is that the reading at the ballast, according to the manual, SHOULD be about 13.8 - 14.45 at 80* while running, which is what I have (the manual says it can be within half volt)........so I figured I was ok there.    :clueless:
 :banghead: Man I hate electrical stuff.

I have been running the car all summer this way I figure....I want to get it right though...dont want to get stranded one day due to this...

*********update
7am 11/27
I checked everything one more time.

The voltage drop difference doesnt happen at all until I put the alternator and VR back into the equation....ie when its running...

With the VR disconnected, but the alt hooked up (both fields) The voltage at the purple VR wire (disconnected) is 11.8 and the voltage at the choke heater is the same....the VR voltage does drop when I plug the choke back in by about .5 volt.

SO then I stuck a pin in the purple VR wire with it hooked up to the VR (everything else connected too) and the voltage was 15.8 at the wire but less at the battery....

I think I am just going to pull the lt and run it down to have tested and pickup a new VR too.....
Title: Re: 16.4 volts at the battery
Post by: shadango on November 27, 2009 - 12:12:52 pm
Had the alternator checked...twice, two different places...they say its fine.

Put a new VR in and no real change.

I did find that when I moved the harness plug at the firewall up and down I got about a half volt change.....so looked in to that.

The small brown wire wasnt seated all the way in the plug and the wire for the black wire came out altogether from the plug.

I am SO pissed.    I paid Bill Evans good money for the harnesses and now this is the SECOND failure at a "new" harness connection. I shouldnt have to fix a brand new harness!!! :villagers:

I soldered the brown and black wires to the clips and reinserted....So now at the connector no major change when I move it.

Now my voltage at the battery while running and everything plugged in is about 15.1 to 15.2 volts at idle.  If I unplug the choke heater it drops another .2 volts or so....at the ballast I an getting 14.6 volts....

At least now it seems reasonable compared to the 16.4 I was getting before at the battery.

A an aside, the guy at autozone said that 13-16 volts is considered Ok for battery voltage level.......  :dunno:






Title: Re: 16.4 volts at the battery
Post by: quagmire on November 27, 2009 - 05:49:43 pm
That's still on the high side, but you can now see the importance of checking the wiring.  You may want to check the rest of the harness connections on that circuit out too, wouldn't surprise me if you still have another iffy connection.  Seems like that harness has some quality control problems.
Title: Re: 16.4 volts at the battery
Post by: shadango on May 07, 2017 - 06:22:31 pm
Ok...so WOW.....This is an 7.5 year old thread!   

I didnt even realize I had the car that long....LOL

Reviving it rather than start a new one since its the same question part deux.

I just installed the crackedback headlight relay setup so I figured now was a good time to look at stuff electrical again.

Since my original post, I have been running the car with high voltage.......so far, no issues.  In fact, pretty sure I still have the same battery even!

I am still running high.....15.7 - 15.8 when cold at high idle....and it comes down to 15.6 or so when warmed up at idle......havent checked it HOT yet.  This is measured on a voltmeter AND the summit in car voltage gauge.

Now, drop into gear and turn the lights on now and she comes down to very fidgety 12.8 or so and lights flicker etc until I give her gas and bring the rpms up....(before the relay kit it would be a little higher voltage as I recall, so its a true indication that the relay kit IS delivering more power to the lights!).  The car is cammed and has always had a very rough in-drive idle....

Voltage at the BLUE wire at the alternator is 14.8 while running (with the battery voltage showing 15.7 or so)

I disconnected and probed the green wire at the alternator and connected my meters other lead to ground....about 1500 OHM, and that is with the VR plugged in.   Unplug the VR and it goes to no connection......that seems like thats what SHOULD happen....so I think the  green wire is NOT going to ground on its own....just when plugged in at the VR.

I even swapped in another VR, checked its grounds, even ran a separate ground from the VR case to the battery.  NO CHANGE AT ALL.

Wiggled the two wires on the alternator, wiggles wires at the firewall....no change.

The manual says "check the ignition switch circuit between the battery terminal of ignition switch and voltage regulator"

Not sure I ever did that way back then.

Its a different alternator since then, having had one come apart on me on the way to carlisle a couple years ago.....

The main ground at the radiator support up front is clean as is the ground cable from the battery cable to it.....cable to engine is good....all the obvious stuff seems right.

Any new thoughts on my conundrum almost 8 years later???  LOL

Should I even worry at this point ??    :bigsmile:  I mean its been over 7 years....but still, it bugs me not knowing "why".

Title: Re: 16.4 volts at the battery
Post by: dodj on May 07, 2017 - 10:19:27 pm
First, clean ALL connections. Valve cover connector, bulkhead connector, fuse link connector, battery connectors, start relay connections, VR ground, and alt connections. See if it changes. (charging voltage)
Title: Re: 16.4 volts at the battery
Post by: shadango on May 08, 2017 - 07:11:03 pm
So how much would the negative battery cable to the engine factor into the system pushing  too much voltage? 

I started messing with that and realized the bolt its attached to (steering pump to black upper bolt) goes into a water jacket....its about the only thing I havent played with.....

The fusible link etc was new when I started having the overcharging state. I used dielectric grease on the connections at the starter relay and they look fine..

Title: Re: 16.4 volts at the battery
Post by: Bullitt- on May 09, 2017 - 12:02:25 am
I'd be looking at the Blue wire to the voltage regulator that I think is the same power that is supplied for the ignition.
As I understand it that is what the VR monitors to see if the battery needs more or less charging (should be same as battery voltage) so if it's not connected well the VR is fooled into thinking it should make the alternator send more juice.
RE: the ground cable, I'd think if it were a problem cranking the car would be an issue. 
Title: Re: 16.4 volts at the battery
Post by: shadango on May 09, 2017 - 05:11:07 am
Yeah that blue wire is the one that also feeds the choke and a couple other things.....and connects to the one field connector on the alternator.....thats the one reading 14.8 volts and I cant see any issues with it....
Title: Re: 16.4 volts at the battery
Post by: Bullitt- on May 09, 2017 - 08:37:57 am
It's loosing a volt somewhere ... recently saw a post that someone had a Ammeter that had high resistance, also this power runs trough the steering column harness & plug which is a week link.

Do you have a ground strap from the motor to the firewall?... don't know if not having one would cause this but the factory put one there for a reason..
Title: Re: 16.4 volts at the battery
Post by: shadango on May 09, 2017 - 10:14:29 am
It's loosing a volt somewhere ... recently saw a post that someone had a Ammeter that had high resistance, also this power runs trough the steering column harness & plug which is a week link.

Do you have a ground strap from the motor to the firewall?... don't know if not having one would cause this but the factory put one there for a reason..

I have a ground strap from the fireall/ecu to the motor (valve cover bolt) and one from the firewall/VR to the same bolt.  I ran a separate temporary jumper wire from the VR/firewall to the battery negative and no change.

My ammeter has been bypassed (one of the first things I did years ago).

Title: Re: 16.4 volts at the battery
Post by: shadango on May 14, 2017 - 01:53:09 pm
So looking at my fusible link connector I saw that it looked like it had melted a little

(http://i349.photobucket.com/albums/q391/shadango_bucket/cuda%20ignition%20and%20wiring/20170513_200356_zpsgjyaio6w.jpg) (http://s349.photobucket.com/user/shadango_bucket/media/cuda%20ignition%20and%20wiring/20170513_200356_zpsgjyaio6w.jpg.html)

I pulled it apart and found this:

(http://i349.photobucket.com/albums/q391/shadango_bucket/cuda%20ignition%20and%20wiring/20170514_130819_zpsruorjgb4.jpg) (http://s349.photobucket.com/user/shadango_bucket/media/cuda%20ignition%20and%20wiring/20170514_130819_zpsruorjgb4.jpg.html)

I was thinking maybe THAT was contributing to the high voltage reading......
I replaced the spade with a new one...crimped and a little solder....reassembled.

No luck.  Same high readings.

Even disconnected the choke, no change.

Back to the drawing board.

At this point all I can figure is that the problem must be on the bulkhead or dash side of the car.
Title: Re: 16.4 volts at the battery
Post by: 73plymouth440 on May 14, 2017 - 09:41:05 pm
Was having the same problem with my 73 barracuda although my stock gage was showing an over charge. For me not was  from ncorrectly connecting the wire to my alternatorafter thathad been replaced.
Title: Re: 16.4 volts at the battery
Post by: 734406pk on May 15, 2017 - 10:38:12 am
I'd be looking at the Blue wire to the voltage regulator that I think is the same power that is supplied for the ignition.
As I understand it that is what the VR monitors to see if the battery needs more or less charging (should be same as battery voltage) so if it's not connected well the VR is fooled into thinking it should make the alternator send more juice.
RE: the ground cable, I'd think if it were a problem cranking the car would be an issue.

 :iagree: The blue wire is where the regulator senses system voltage and when functioning properly, will try to field the alternator to maintain (regulate) 14 volts +- .2 volts. Raise the idle when testing the alternator to 1200-1500 rpm. The amperage output at idle too low to test properly, especially a roudback alternator. Based on the testing that you have done already, it appears that your voltage regulator and alternator are working, but there is a voltage drop on the blue wire feeding power to the regulator, throwing the alternator output voltage out of range. Do you have a hand held digital voltmeter for testing?
Title: Re: 16.4 volts at the battery
Post by: shadango on May 15, 2017 - 12:15:07 pm
:iagree: The blue wire is where the regulator senses system voltage and when functioning properly, will try to field the alternator to maintain (regulate) 14 volts +- .2 volts. ......<snip>......but there is a voltage drop on the blue wire feeding power to the regulator, throwing the alternator output voltage out of range. Do you have a hand held digital voltmeter for testing?

Yes I have a meter...

But  HOW do I test it?   What am I looking for? 

I had previously tested the blue/purple wire at the VR and it was lower in voltage....but should I be testing that when connected to the VR or disconnected?  With engine running or not?

All the connectors seem ok...choke connector, ballast connector, etc
Title: Re: 16.4 volts at the battery
Post by: 734406pk on May 15, 2017 - 08:38:37 pm
Yes I have a meter...

But  HOW do I test it?   What am I looking for? 

I had previously tested the blue/purple wire at the VR and it was lower in voltage....but should I be testing that when connected to the VR or disconnected?  With engine running or not?

All the connectors seem ok...choke connector, ballast connector, etc

First thing is I'm sorry you have been dealing with this overcharging issue for so long! :-\
I'll explain how to test your charging system for you. 40+ years as a service professional, I do this on a daily basis. You are looking to locate the source of the voltage drop (resistance) in the charging system. We will test the charging system running and loaded, VR connected with the engine rpm set at 1200-1500 rpm for accuracy.
 To start off; In a perfect world there will be no difference between the battery positive terminal voltage and the voltage reading at the blue wire (at the VR).On the ground side, the VR attaching ground screw, and battery negative terminal. The alternator positive output terminal and the battery + terminal and last the alternator case ground and the battery negative terminal. Does this make sense?
Title: Re: 16.4 volts at the battery
Post by: shadango on May 18, 2017 - 10:50:39 am
 So I should use the pin method and see what the vr is seeing when plugged in? Or disconnect and check?
Title: Re: 16.4 volts at the battery
Post by: 734406pk on May 18, 2017 - 08:04:20 pm
So I should use the pin method and see what the vr is seeing when plugged in? Or disconnect and check?

Ok when your ready we can start at the beginning. Completely reconnect the charging system so it's ready to go, then start the engine and set the idle to 1200-1500 rpm. Turn on all the accessories in the car, headlights on high beam, interior light etc. Leave the flashers/blinker off. We want a constant load. Now take these readings:

A- Battery voltage. Positive test lead on the positive battery POST (not the battery wire terminal). Negative test lead to the negative battery POST (not the wire terminal. Write down the voltage reading as A.

If your digital volt meter doesn't auto-range, select 4 Volt DC scale for better accuracy. Then-

B- Alternator output ground side voltage drop: Connect the negative test lead to a clean bare metal spot on the alternator housing. Connect the positive test lead to the Negative battery post, (not the battery wire terminal). Write down the reading as B.

C- Alternator output positive side voltage drop: Connect the positive test lead to the output (+) terminal on the alternator, attach the negative test lead to the battery Positive Post. Write down this reading as C.

Here's a how to video: https://www.youtube.com/watch?v=_B0LjwQbUbg (https://www.youtube.com/watch?v=_B0LjwQbUbg)

Turn the idle speed back down and shut off all the accessories. Turn off the engine. Post your readings when you have a chance.  :thumbsup:
Title: Re: 16.4 volts at the battery
Post by: shadango on May 19, 2017 - 09:10:54 am
Ok when your ready we can start at the beginning. Completely reconnect the charging system so it's ready to go, then start the engine and set the idle to 1200-1500 rpm. Turn on all the accessories in the car, headlights on high beam, interior light etc. Leave the flashers/blinker off. We want a constant load. Now take these readings:

A- Battery voltage. Positive test lead on the positive battery POST (not the battery wire terminal). Negative test lead to the negative battery POST (not the wire terminal. Write down the voltage reading as A.

If your digital volt meter doesn't auto-range, select 4 Volt DC scale for better accuracy. Then-

B- Alternator output ground side voltage drop: Connect the negative test lead to a clean bare metal spot on the alternator housing. Connect the positive test lead to the Negative battery post, (not the battery wire terminal). Write down the reading as B.

C- Alternator output positive side voltage drop: Connect the positive test lead to the output (+) terminal on the alternator, attach the negative test lead to the battery Positive Post. Write down this reading as C.

Here's a how to video: https://www.youtube.com/watch?v=_B0LjwQbUbg (https://www.youtube.com/watch?v=_B0LjwQbUbg)

Turn the idle speed back down and shut off all the accessories. Turn off the engine. Post your readings when you have a chance.  :thumbsup:

Thanks for this!  Will test as soon as I can.
Title: Re: 16.4 volts at the battery
Post by: 73_Cuda_4_Me on May 19, 2017 - 09:15:31 am
 :iagree:   :worshippy

Others may wonder about the procedure listed by 734406pk, but they are right on.. it's measuring the voltage 'drop' from end to end of each circuit... all wiring and connections provide a resistance to current flow.. the more resistance in the circuit, the more drop there will be from one end to the other... by using low voltage scale on meter, you can read what the difference in voltage is from one end of the circuit to the other... the higher the voltage reading end-to-end, the more resistance there is in that circuit... the worse the voltage drop is... BAD

Ideally, you want ZERO volt readings (no resistance end to end) on the circuits described, but there will always be some resistance in the wires/connections.

 :thumbsup:
Title: Re: 16.4 volts at the battery
Post by: 734406pk on May 19, 2017 - 09:53:11 am
:iagree:   :worshippy

Others may wonder about the procedure listed by 734406pk, but they are right on.. it's measuring the voltage 'drop' from end to end of each circuit... all wiring and connections provide a resistance to current flow.. the more resistance in the circuit, the more drop there will be from one end to the other... by using low voltage scale on meter, you can read what the difference in voltage is from one end of the circuit to the other... the higher the voltage reading end-to-end, the more resistance there is in that circuit... the worse the voltage drop is... BAD

Ideally, you want ZERO volt readings (no resistance end to end) on the circuits described, but there will always be some resistance in the wires/connections.

 :thumbsup:

Thank You!  :2thumbs: This method for testing voltage drop may be a little tough to understand at first (it was for me!) but its incredibly accurate. The plan is to test the entire charging system this way.
Title: Re: 16.4 volts at the battery
Post by: 73_Cuda_4_Me on May 19, 2017 - 11:31:21 am
The only thing I would add to this is that IF you get a large voltage drop when reading to either of the battery posts, the first thing to check is the battery cable to battery post connections...

they always seem to 'corrode' first, and ground post faster than positive post... (it will build up an oxidized layer between the inside connector surfaces and post surfaces). Use a battery terminal cleaner/wire brush to remove the corrosion, and apply some dielectric grease to the connectors when re-attaching them, to help prevent buildup in the future.
Title: Re: 16.4 volts at the battery
Post by: shadango on May 19, 2017 - 12:39:55 pm
Ok, here are my results....testing at 1400-1500 rpms, high beams on, heater blower on full, interior dome light on (I didnt turn on the stereo or wipers)

Quote
A- Battery voltage. Positive test lead on the positive battery POST (not the battery wire terminal). Negative test lead to the negative battery POST (not the wire terminal. Write down the voltage reading as A.

15.8


Quote
B- Alternator output ground side voltage drop: Connect the negative test lead to a clean bare metal spot on the alternator housing. Connect the positive test lead to the Negative battery post, (not the battery wire terminal). Write down the reading as B.

.026 volts on the rear half of the case,  .018 volts on the front half of the case


Quote
C- Alternator output positive side voltage drop: Connect the positive test lead to the output (+) terminal on the alternator, attach the negative test lead to the battery Positive Post. Write down this reading as C.

.45 volts average .... .42 to .50  fluctuations

So, going by what the guy in the video said (want no more than .5 volts in C and no more than .2 volts in B)  I am doing ok so far ,, yes?
Title: Re: 16.4 volts at the battery
Post by: 734406pk on May 19, 2017 - 07:59:40 pm
Ok so far:

A- 15.8 volts= You are over charging.
B- 0.018-0.026 ground side voltage drop= excellent! You have a clean ground path from the alternator to the battery.
C- .42-.50 Output side voltage drop= On the high side! Do you have an ammeter bypass installed btw? It's not causing your overcharging issue, but we should clean that up after the overcharge.

To continue:
Start the engine and turn on all accessories as before and set idle speed to 1200-1500 rpm

D- VR case voltage drop. Negative test lead to battery negative post. Positive test lead to the metal CASE (not an attaching bolt) of the VR. You may need to scratch a tiny bit of paint off the case to get a reading. Write down this reading as D.

E- Alternator F+ voltage drop. Positive test lead to the positive battery post, negative test lead to the BLUE alternator field wire terminal. Try to slip the test lead probe inside of the slip on connector for a good reading. Write down the reading as E.

F- VR sensing lead voltage drop. Now use your pin through the blue wire at the VR. Connect the negative test lead to the pin. Connect the positive test lead to the battery positive post. Write down this reading as F.

You can shut down the car now.

I suspect that the cause of the overcharging will be within these three test points. Post your readings or any questions when you can. Good luck and work safe!


Title: Re: 16.4 volts at the battery
Post by: 734406pk on May 19, 2017 - 09:42:22 pm
The only thing I would add to this is that IF you get a large voltage drop when reading to either of the battery posts, the first thing to check is the battery cable to battery post connections...

they always seem to 'corrode' first, and ground post faster than positive post... (it will build up an oxidized layer between the inside connector surfaces and post surfaces). Use a battery terminal cleaner/wire brush to remove the corrosion, and apply some dielectric grease to the connectors when re-attaching them, to help prevent buildup in the future.

 :iagree: The alternator positive output voltage drop is on the high side. Corrosion at the battery terminal could easily be the cause. We will test it later. The overcharging is the main issue at the moment.
Title: Re: 16.4 volts at the battery
Post by: shadango on May 19, 2017 - 10:31:19 pm
:iagree: The alternator positive output voltage drop is on the high side. Corrosion at the battery terminal could easily be the cause. We will test it later. The overcharging is the main issue at the moment.
I just cleaned the posts and connections a week ago or so when I revived this thread.
Title: Re: 16.4 volts at the battery
Post by: 734406pk on May 19, 2017 - 10:37:02 pm
I just cleaned the posts and connections a week ago or so when I revived this thread.

Ok. Do you have an ammeter bypass installed?
Title: Re: 16.4 volts at the battery
Post by: shadango on May 20, 2017 - 05:31:42 am
Ok. Do you have an ammeter bypass installed?

Yes -- did that many many moons ago.
Title: Re: 16.4 volts at the battery
Post by: 734406pk on May 20, 2017 - 09:45:05 am
Yes -- did that many many moons ago.

OK I though so. There is some minor resistance on the alternator positive output side for some reason, we'll get to that later. :thumbsup:
Title: Re: 16.4 volts at the battery
Post by: shadango on May 22, 2017 - 10:35:20 am
OK I though so. There is some minor resistance on the alternator positive output side for some reason, we'll get to that later. :thumbsup:
Ok cool.....

As an aside, and maybe I should do this in a separate thread or maybe not....

We were at a car show 3 hours from home over the weekend....car was fine all the way there.  parked and it sat for 9 hours or so.  Started it up and the dash fuel and temp gauges legged to the right.  The aftermarket temp gauge showed normal and of course the car was cold.

Shut it off for a minute, restarted, and it was fine for a little bit then pegged again....drove a ways like that til we took a break, shut it down....next start up it was fine the rest of the way home.

I think I recall this happening once very early in my ownership of the fish.......some 7+ years ago.

The voltmeter gauge still showed the normal high charging status while it was happening.
Title: Re: 16.4 volts at the battery
Post by: 734406pk on May 22, 2017 - 08:15:43 pm
Ok cool.....

As an aside, and maybe I should do this in a separate thread or maybe not....

We were at a car show 3 hours from home over the weekend....car was fine all the way there.  parked and it sat for 9 hours or so.  Started it up and the dash fuel and temp gauges legged to the right.  The aftermarket temp gauge showed normal and of course the car was cold.

Shut it off for a minute, restarted, and it was fine for a little bit then pegged again....drove a ways like that til we took a break, shut it down....next start up it was fine the rest of the way home.

I think I recall this happening once very early in my ownership of the fish.......some 7+ years ago.

The voltmeter gauge still showed the normal high charging status while it was happening.

That's a symptom of a bad ground or faulty voltage limiter. I would run an extra ground wire from the dash frame to the car body. The dash lights ground through the dash frame.
Title: Re: 16.4 volts at the battery
Post by: xtopfuel on May 23, 2017 - 05:03:20 am
 :iagree:
should he clean and lube the bulkhead
Title: Re: 16.4 volts at the battery
Post by: shadango on May 23, 2017 - 09:56:41 am
:iagree:
should he clean and lube the bulkhead

Afraid to even TOUCH the bulkhead....what a hornets nest if I screw something up....LOL
Title: Re: 16.4 volts at the battery
Post by: shadango on May 23, 2017 - 09:58:31 am
That's a symptom of a bad ground or faulty voltage limiter. I would run an extra ground wire from the dash frame to the car body. The dash lights ground through the dash frame.

I am gonna get in there and pull the switch panel and see if the ground is OK....My wipers dont park all the way down and I know the ground at the switch is the first thing to check, so I will be in there anyways.....

I already ran a second ground wire as you suggested, a while back.  Will check that as well.
Title: Re: 16.4 volts at the battery
Post by: xtopfuel on May 24, 2017 - 06:22:41 am
I had several same issues on my 72 and yes scary removing bulk head but came right off, cleaned with electric cleaner CRC then loads of dialectic lube and all fixed including wipers parking
Title: Re: 16.4 volts at the battery
Post by: shadango on May 24, 2017 - 06:30:33 am
I had several same issues on my 72 and yes scary removing bulk head but came right off, cleaned with electric cleaner CRC then loads of dialectic lube and all fixed including wipers parking

Did you do just the engine side or the inside side as well?
Title: Re: 16.4 volts at the battery
Post by: 734406pk on May 24, 2017 - 08:56:20 am
Afraid to even TOUCH the bulkhead....what a hornets nest if I screw something up....LOL

Is the dash harness/bulkhead connector the original?
Title: Re: 16.4 volts at the battery
Post by: shadango on May 24, 2017 - 11:57:15 am
Is the dash harness/bulkhead connector the original?

As far as I can tell yes....doesnt seem to be in bad shape, but with anything that old, trying to not "fix what aint broke" because I may break something...LOL
Title: Re: 16.4 volts at the battery
Post by: 734406pk on May 24, 2017 - 04:40:29 pm
Got yah! I would rather test the harness first before disturbing it. This way we can be 100% sure where the problem is.
Title: Re: 16.4 volts at the battery
Post by: xtopfuel on May 24, 2017 - 06:31:19 pm
engine bay side only
Title: Re: 16.4 volts at the battery
Post by: 734406pk on May 24, 2017 - 08:45:18 pm
engine bay side only

Thanks! I remember reading in i prior post that the engine harness was replaced a some point. With electrical issues like this, I have found it is best to find the problem first, then do the repair. After that you can re-measure voltage drops to verify that you have corrected the issue.  Electrical issues are tough since you can't "see"  what's going on only measure it.
Title: Re: 16.4 volts at the battery
Post by: shadango on May 25, 2017 - 03:06:13 pm
Just to stay current, I havent forgotten this thread.....just havent had the time to do the second stage of testing.  Was out of town last week at a big show. Then the kiddos were involved in stuff etc.......life. LOL :bigsmile:

Gonna jump back on it as soon as I can find the time, hopefully this evening or tomorrow. i really do appreciate the ongoing help!
Title: Re: 16.4 volts at the battery
Post by: shadango on May 25, 2017 - 07:54:14 pm
Ok so far:

A- 15.8 volts= You are over charging.
B- 0.018-0.026 ground side voltage drop= excellent! You have a clean ground path from the alternator to the battery.
C- .42-.50 Output side voltage drop= On the high side! Do you have an ammeter bypass installed btw? It's not causing your overcharging issue, but we should clean that up after the overcharge.

To continue:
Start the engine and turn on all accessories as before and set idle speed to 1200-1500 rpm

D- VR case voltage drop. Negative test lead to battery negative post. Positive test lead to the metal CASE (not an attaching bolt) of the VR. You may need to scratch a tiny bit of paint off the case to get a reading. Write down this reading as D.

E- Alternator F+ voltage drop. Positive test lead to the positive battery post, negative test lead to the BLUE alternator field wire terminal. Try to slip the test lead probe inside of the slip on connector for a good reading. Write down the reading as E.

F- VR sensing lead voltage drop. Now use your pin through the blue wire at the VR. Connect the negative test lead to the pin. Connect the positive test lead to the battery positive post. Write down this reading as F.

You can shut down the car now.

I suspect that the cause of the overcharging will be within these three test points. Post your readings or any questions when you can. Good luck and work safe!

Ok, just did this section

D - VR case voltage drop....I had to set the scale low to get anything.....got .000 to .001

E - Alternator F+ voltage drop .... had to swap my blue and green field wires to do this......got 1.2 to 1.4

F - couldnt get pin thru the actual wire...so I back probed the blue wire at the connecter with a safety pin.......got 1.4
Title: Re: 16.4 volts at the battery
Post by: 734406pk on May 25, 2017 - 08:41:31 pm
Quote:
Ok, just did this section

D - VR case voltage drop....I had to set the scale low to get anything.....got .000 to .001

E - Alternator F+ voltage drop .... had to swap my blue and green field wires to do this......got 1.2 to 1.4

F - couldnt get pin thru the actual wire...so I back probed the blue wire at the connecter with a safety pin.......got 1.4

Ok, nice job!

D= Very good! You have an excellent ground to the VR case.
E & F= The voltage drop here is very high. This is why the alternator is over charging.

Now on to find the resistance...
Looking at the new engine harness at the bulkhead connector,engine side,  you will see a blue wire on pin 23.
We need to connect the positive volt meter lead to the positive battery terminal and the negative lead back probe the blue wire connector at pin 23. Load the electrical system as before and write down this reading as G.
This test will check the integrity of the engine wire harness ignition power feed circuit. There's a substantial load on this blue wire.

Title: Re: 16.4 volts at the battery
Post by: Bullitt- on May 25, 2017 - 09:02:20 pm
I'm diggin what your doing here Andy...
What I've read about as just not getting accurate signal to the VR in a outstanding step by step diagnosis.  :woo:
Title: Re: 16.4 volts at the battery
Post by: 734406pk on May 25, 2017 - 09:46:38 pm
Thank You Wade! Glad to help, Shadango needs a break with this overcharging issue! So far, low voltage to the blue "sense" wire is causing the VR to drive the alternator output voltage high out of range. The next step is to pinpoint where the resistance is.  :2thumbs:
Title: Re: 16.4 volts at the battery
Post by: xtopfuel on May 26, 2017 - 04:38:26 am
 :ylsuper: 73440
Title: Re: 16.4 volts at the battery
Post by: shadango on May 26, 2017 - 05:42:29 am

Looking at the new engine harness at the bulkhead connector,engine side,  you will see a blue wire on pin 23.
We need to connect the positive volt meter lead to the positive battery terminal and the negative lead back probe the blue wire connector at pin 23. Load the electrical system as before and write down this reading as G.
This test will check the integrity of the engine wire harness ignition power feed circuit. There's a substantial load on this blue wire.

So it will be the same color blue (same wire) as at the VMR right?
Title: Re: 16.4 volts at the battery
Post by: 734406pk on May 26, 2017 - 08:36:37 am
Quote:
So it will be the same color blue (same wire) as at the VMR right?

Yes it should be the same color Blue (same wire in the engine harness) on pin 23. This wire may have a stripe or tracer on it. It's energized with the key in the "run" position. Don't confuse with Pin 20, it could also be a blue (no stripe) wire but it powers the a/c compressor. Be sure to back probe the right one.
Title: Re: 16.4 volts at the battery
Post by: shadango on May 26, 2017 - 01:24:06 pm
Quote:
So it will be the same color blue (same wire) as at the VMR right?

Yes it should be the same color Blue (same wire in the engine harness) on pin 23. This wire may have a stripe or tracer on it. It's energized with the key in the "run" position. Don't confuse with Pin 20, it could also be a blue (no stripe) wire but it powers the a/c compressor. Be sure to back probe the right one.

Thanks.  I dont have A/C.

Do you have a schematic handy as far Pin location numbers?  I am sure its in my manual somewhere if not....
Title: Re: 16.4 volts at the battery
Post by: 734406pk on May 26, 2017 - 07:01:21 pm
Here is a link to find and download your diagram, the .jpg was too large to post:
http://www.mymopar.com/72to76_wiring.htm (http://www.mymopar.com/72to76_wiring.htm)
Title: Re: 16.4 volts at the battery
Post by: shadango on May 26, 2017 - 07:07:20 pm
Here is a link to find and download your diagram, the .jpg was too large to post:
[url]http://www.mymopar.com/72to76_wiring.htm[/url] ([url]http://www.mymopar.com/72to76_wiring.htm[/url])


Yikes...looks like 'sghetti.  LOL

I was hoping more for a picture of the engine side of the bulkhead pointing out the numbering....but It wont be hard to figure it out....cant be more than one wire that color in that particular plug.....gonna check this reading hopefully tomorrow....if the weather holds out.

I suppose that this test will just confirm that the drop is somewhere between the connector at the bulkhead and the end of the VMR blue wire right? It will show a 1.4 or so voltage drop....And if it DOESNT , then the next step is to measure between the bulkhead connector and something inside the car???????
Title: Re: 16.4 volts at the battery
Post by: 734406pk on May 26, 2017 - 07:22:57 pm
Quote:
I suppose that this test will just confirm that the drop is somewhere between the connector at the bulkhead and the end of the VMR blue wire right? It will show a 1.4 or so voltage drop....And if it DOESNT , then the next step is to measure between the bulkhead connector and something inside the car???????

That's right! If we back probe pin 23 on the engine side and we have a low voltage drop, the issue is in the engine harness. If we have a high voltage drop, the issue is somewhere in between the bulkhead connector and the battery positive terminal 
Title: Re: 16.4 volts at the battery
Post by: 73440 on May 26, 2017 - 09:10:00 pm
(http://i1302.photobucket.com/albums/ag136/73440/20170526_195724_zpsvpajyvur.jpg) (http://s1302.photobucket.com/user/73440/media/20170526_195724_zpsvpajyvur.jpg.html)

Taken from 73 FSM.

And GO PENS !!!
Title: Re: 16.4 volts at the battery
Post by: 734406pk on May 26, 2017 - 10:10:21 pm
Perfect! That drawing will make it easy to find! :2thumbs:
Title: Re: 16.4 volts at the battery
Post by: shadango on May 27, 2017 - 07:16:25 am
([url]http://i1302.photobucket.com/albums/ag136/73440/20170526_195724_zpsvpajyvur.jpg[/url]) ([url]http://s1302.photobucket.com/user/73440/media/20170526_195724_zpsvpajyvur.jpg.html[/url])

Taken from 73 FSM.

And GO PENS !!!

AWESOME! Thanks!   (As an aside, and not wanting to clutter up this thread with side bars, I just have to say....Love this forum......most of the stuff I have ever done on this car since 2007 has been made possible only by the great folks on this forum.....whether to just give me the push I need to do something or the complete "how to" info......what did folks do before Al Gore invented the interweb!? LOL)
Title: Re: 16.4 volts at the battery
Post by: 734406pk on May 27, 2017 - 07:49:06 pm
Happy to help a fellow E-Body owner!  :2thumbs: You are close to finding the problem Shadango!
Title: Re: 16.4 volts at the battery
Post by: xtopfuel on May 28, 2017 - 07:21:28 am
You have been quite helpful, a true team player 73440
Title: Re: 16.4 volts at the battery
Post by: shadango on May 28, 2017 - 08:14:57 pm
Now on to find the resistance...
Looking at the new engine harness at the bulkhead connector,engine side,  you will see a blue wire on pin 23.
We need to connect the positive volt meter lead to the positive battery terminal and the negative lead back probe the blue wire connector at pin 23. Load the electrical system as before and write down this reading as G.
This test will check the integrity of the engine wire harness ignition power feed circuit. There's a substantial load on this blue wire.

Ok, so I test fitted my back probing at 23 before cranking up , just to be safe.....had that figured out....then started her up , swicthed stuff on etc....and checked the voltage at the battery.....it had dropped to 15.4 or so.

So I figured that my messing with pin 23 was what helped there.....droped .4 volts from my usual 15.8.

Did the test you prescribed, got .7-.8....so I went ahead an pulled tha twire from the harness plug, resoldered the connection, cleaned as best I could (what the hell do you use to clean the bulkhead connections?), greased it up and stuck it all together again...took a while since I had to fight a big rain storm.,..LOL

Anyways, after reassembly I measured again....had a reading still of .8.   Now, if I turned everything off except the dome light (since I forgot it), I got a reading of .6.

Also, before messing with soldering the wire at 23, I also checked for voltage drop between wire 23e and the left plugs on the ballast.....got .2 on the top and .5 on the bottom......if that helps at all. LOL

After all this was done, I am still reading at 15.2-15.4 volts at the battery ---that does make my summit gauge read a lot better rather than pegged....it reads at 15-15.5,

SO SOMEHOW I picked up .4 volts.....maybe it was the wire at pin 23 or maybe not.....    :pullinghair: :dunno:
Title: Re: 16.4 volts at the battery
Post by: 734406pk on May 28, 2017 - 09:16:31 pm
Quote:
Anyways, after reassembly I measured again....had a reading still of .8. 

Ok to be sure here, you have 0.8 volt drop at the engine side of pin 23? This reading is with the electrical system fully loaded, yes?
Title: Re: 16.4 volts at the battery
Post by: shadango on May 29, 2017 - 07:14:46 am
Quote:
Anyways, after reassembly I measured again....had a reading still of .8. 

Ok to be sure here, you have 0.8 volt drop at the engine side of pin 23? This reading is with the electrical system fully loaded, yes?
Yes sir, that's correct.
Title: Re: 16.4 volts at the battery
Post by: 734406pk on May 29, 2017 - 10:02:12 am
OK Great! That reading G shows that there is major voltage drop between the battery positive terminal and pin 23.

Quote:
So I figured that my messing with pin 23 was what helped there.....droped .4 volts from my usual 15.8.
 :iagree:
There is also a minor voltage drop in the engine harness, but we'll get back to that one later, we want to find the big one first.

 So now restart the car, idle speed 1200 rpm and fully load the electrical system (high beams on etc)as before. Connect you positive volt meter lead to the positive battery post and the with negative test lead, back probe pin 16 on the bulkhead connector-engine side. Write down this reading as H.

 This will test the power feed (fuse link) into the car. With the ammeter bypassed, the entire electrical load passes through this one wire. :eek7:
Title: Re: 16.4 volts at the battery
Post by: 734406pk on June 08, 2017 - 09:18:26 pm
So looking at my fusible link connector I saw that it looked like it had melted a little

([url]http://i349.photobucket.com/albums/q391/shadango_bucket/cuda%20ignition%20and%20wiring/20170513_200356_zpsgjyaio6w.jpg[/url]) ([url]http://s349.photobucket.com/user/shadango_bucket/media/cuda%20ignition%20and%20wiring/20170513_200356_zpsgjyaio6w.jpg.html[/url])

I pulled it apart and found this:

([url]http://i349.photobucket.com/albums/q391/shadango_bucket/cuda%20ignition%20and%20wiring/20170514_130819_zpsruorjgb4.jpg[/url]) ([url]http://s349.photobucket.com/user/shadango_bucket/media/cuda%20ignition%20and%20wiring/20170514_130819_zpsruorjgb4.jpg.html[/url])

I was thinking maybe THAT was contributing to the high voltage reading......
I replaced the spade with a new one...crimped and a little solder....reassembled.

No luck.  Same high readings.

Even disconnected the choke, no change.

Back to the drawing board.

At this point all I can figure is that the problem must be on the bulkhead or dash side of the car.


This pic shows a problem with the fuse link connector. Resistance impedes current flow and generates heat in the process. This issue should be looked into.  :thumbsup:
Title: Re: 16.4 volts at the battery
Post by: shadango on June 09, 2017 - 09:13:06 am
I replaced the connector already.
Title: Re: 16.4 volts at the battery
Post by: 734406pk on June 09, 2017 - 11:44:43 pm
I replaced the connector already.

The fuse link has been replaced, understood... What concerns me is this connector show no sign of corrosion. Something else is wrong here.
Title: Re: 16.4 volts at the battery
Post by: shadango on June 10, 2017 - 07:00:29 am
I didn't replace the who fusible link.....just replaced the spade connector on it.

I am thinuking it was a poor crimp/connection from when it was new maybe.
Title: Re: 16.4 volts at the battery
Post by: 734406pk on June 10, 2017 - 10:34:15 am
I highly recommend testing the voltage drop here (pin 16, fuse link) with the electrical system fully loaded. It just may be the cause of most of the voltage drop measured already.
Title: Re: 16.4 volts at the battery
Post by: shadango on June 12, 2017 - 01:45:42 pm
I highly recommend testing the voltage drop here (pin 16, fuse link) with the electrical system fully loaded. It just may be the cause of most of the voltage drop measured already.

Ok, will check the next time I get a chance.

We were at an event this past weekend and once again had a problem with the gas/temp gauges -- this time, not pegged, but DEAD.    Started aboit 20 minutes from the house.  Kicked in and out during the 4 hour trip.  Coming home, they worked 100% fine. Go figure.

I did replace the voltage limiter with a good electronic one (RTE) a ways back.
Title: Re: 16.4 volts at the battery
Post by: 734406pk on June 12, 2017 - 08:58:45 pm
Check the drop when you have time...

quote:
We were at an event this past weekend and once again had a problem with the gas/temp gauges -- this time, not pegged, but DEAD.

Was the oil pressure gauge working correctly at the time the gas/temp gauges were out?
Title: Re: 16.4 volts at the battery
Post by: shadango on June 13, 2017 - 05:19:49 am
Check the drop when you have time...

quote:
We were at an event this past weekend and once again had a problem with the gas/temp gauges -- this time, not pegged, but DEAD.

Was the oil pressure gauge working correctly at the time the gas/temp gauges were out?

I have  a standard gauge cluster so no oil gauge (I have aftermarket gauges for that, water and volts).....
Title: Re: 16.4 volts at the battery
Post by: 734406pk on June 13, 2017 - 10:12:27 pm
Ah, ok. Check the feed wire to the voltage limiter (Black Wire). The connector may be loose or corroded where it slips onto the terminal.
Title: Re: 16.4 volts at the battery
Post by: shadango on July 25, 2017 - 01:18:13 pm
Ah, ok. Check the feed wire to the voltage limiter (Black Wire). The connector may be loose or corroded where it slips onto the terminal.

Geez -- where is the summer going.....

what are the chances I will be able to access the VL from under the dash?

Probably between slim and none and slim left town...LOL

Cause now, the fuel and temp gauges are dead the last few drives.......not coming back like before....hoping its just a wire and not the VL.....

Have to tear out the dash to get to the wire and the VL....and thats a pain.......thinking that pulling the drivers seat so I can go from underneath would be easier, but not sure its a straight shot or not...maybe I can pull the ash tray housing out and go in that way??  Seems to be in the vicinity of where I would need to go,.......????

In the meantime, I have to take the car to have a self-imposed dent looked at.....

And just before Carlisle, the battery died altogether so a new battery now graces the fish.   gauge still showing charging about the same so at least the battery is out of the equation.

I do hope to remember to check the last drop item you suggested soon.....honestly, it just keeps getting back burnered......sheesh.
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Ok, update --- I found that I could pull my stereo out and snake my fat arm up into behind the dash and get a hand on the wires to the VL.

Found that pushing one of the connectors at the VL to one side made it work and oushing the other it quit......worked the connector on and off a few times and same deal.....since I couldnt get to the connector itself this way, I twisted the connector slightly on the VL and it is holding......

After looking online, figured out that the wire in question is the Y harness from the VL to the fuel/temp gauges (its a y cable).

Gonna wait and see if my twisting helps long term....if not I may try to pull just the y harness this way but man I may not get it installed again this way...cant see anything, its all by feel.

To change the actual VL (if the connector at the VL is the issue), the dash will have to come out.  Its one of those electronic VLs with the red LED light on it.  Installed that 5 or 6 years back.

As an aside, you could NEVER do what I did on a new car....LOL...love the old car designs that let you work on stuff!
Title: Re: 16.4 volts at the battery
Post by: 70chall440 on July 27, 2017 - 04:15:53 pm
I don't think you have to pull the cluster to replace the VL; definitely easier to replace if you do but I installed one in my Challenger laying on the floor w/o the drivers seat in. Not super easy but it can be done.
Title: Re: 16.4 volts at the battery
Post by: dodj on July 27, 2017 - 06:39:45 pm
I don't find it that difficult to drop the steering column onto the seat then pull the cluster out enough to change the VL. :2cents:
Title: Re: 16.4 volts at the battery
Post by: shadango on July 29, 2017 - 01:27:00 pm
I don't find it that difficult to drop the steering column onto the seat then pull the cluster out enough to change the VL. :2cents:

I've done that....the switch pod has to come out, the metal dash light assembly has to come out, the gauge cluster bezel has to come out , which for me means removing the tach I have installed, and then the gauge cluster itself has to get pulled out......lots of screws and wires and such.

None of it hard.  But its not a 5 minute job.  LOL  Would rather pursue an easier route though I know thats probably the best way.

Seat comes out with 4 bolts....but seems to me that the location of the VL on MY car (right above/near the column) would make that harder.....didnt seem like it was accessible due to the column?

Title: Re: 16.4 volts at the battery
Post by: shadango on July 29, 2017 - 02:43:46 pm
So now restart the car, idle speed 1200 rpm and fully load the electrical system (high beams on etc)as before. Connect you positive volt meter lead to the positive battery post and the with negative test lead, back probe pin 16 on the bulkhead connector-engine side. Write down this reading as H.

 This will test the power feed (fuse link) into the car. With the ammeter bypassed, the entire electrical load passes through this one wire. :eek7:

Alright so......after figuring out which one was #16 (the big red wire) I ended up pulling the bulkhead connector (engine side) because I realized I could not easily back probe the #16 pin and wanted to look at it.

The red wire has a think rubber insulating boot where it goes it to the plug.  I hesitate to puncture the big red wire....

That said I plugged the connector back in and started the car again and now it stays at 15.0 rather than 15.6-15.8.  Just moments before pulling that connector it was reading 15.6-15.8.....

So obviously disturbing the bulkhead connector did something there.   SO the good news is that I may be on to something here.

The bad news is that the fuel and temp gauge are dead again....LOL...so my twisting the wire didnt make difference....though I ran the car for 60 miles the other night and all was well.  So go figure.

Back to the damn drawing board on that -- not sure if it will be the VL or "just a wire"....looks like ripping it all apart is gonna be required.....

I got my hand on the same wire again on the back of the VL and found it to be completely loose now....even if I push on it and make a connection now, NOTHING.  Weird.  It was a tight connection before. At least I thunk it was....and loike I said it worked for a couple hour drive.

I record my mileage at every fill up and have a seperate temp gauge so its not a huge issue as long as the odometer keeps working.  Truth be told, the gas gauge has never be uber reliable anyways.   It stays at full a long time then starts dropping fast...when it is reading a 1/4 tank it is accrurate because it generally takes 10-11 gallons at that point.  But I rely on the mileage more than the gauge. Just hate to have it not working....and looking "empty" all the time....LOL

Did I mention I hate electrical issues?  LOL
Title: Re: 16.4 volts at the battery
Post by: 734406pk on September 07, 2017 - 10:52:48 pm
Wow! Sorry to leave you hanging, I missed your post somehow! :clueless: Anyway, we'll treat the gauges as a separate issue, so for now : Yes you are on to something! Disturbing the bulkhead connector has made a change in the charging voltage (for the better). We need to get a voltage drop reading to pinpoint the resistance, so positive test lead to the positive battery terminal and negative lead to engine side pin 16. This test will check for resistance in the fusible link main line feeding the cars entire electrical system. Don't worry about damaging the rubber sleeve in back probing, it's highly likely it will be needing replacement anyway.  :thumbsup:
Title: Re: 16.4 volts at the battery
Post by: shadango on November 02, 2017 - 12:00:10 pm
Well -- wow.....its been a while on this...LOL

I finally got to address the gauge issue....turns out it was a faulty ground in the RT-ENG voltage limiter unit....the circuit board grounds to the case, and that ground was bad.

Havent driven the car yet since the fix due to weather, but numerous "starts" and the fuel gauge kicks in every time now.  Hopefully it will not be a recurring issue.

Will get back to the voltage issue at some point....though its ben charging at 14.5-15 lately....so its holding.

I thought I had done a resistance check on the FL already? Maybe not..losing track...LOL
Title: Re: 16.4 volts at the battery
Post by: 734406pk on November 15, 2017 - 08:14:57 pm
Well -- wow.....its been a while on this...LOL

I finally got to address the gauge issue....turns out it was a faulty ground in the RT-ENG voltage limiter unit....the circuit board grounds to the case, and that ground was bad.

Havent driven the car yet since the fix due to weather, but numerous "starts" and the fuel gauge kicks in every time now.  Hopefully it will not be a recurring issue.

Will get back to the voltage issue at some point....though its ben charging at 14.5-15 lately....so its holding.

I thought I had done a resistance check on the FL already? Maybe not..losing track...LOL

Ready when you are! The test for the fuse link is voltmeter positive lead on the positive battery terminal, negative lead on the engine side of the bulkhead connector pin 16. The engine at 1500 rpm with headlights on high beam and all accessories on (max amp load). The voltmeter will read the voltage drop (resistance) through the fuse link. Good luck and post the results when you have time.  :thumbsup: