Amp meter pegged

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diymirage

diymirage

HP@idle > hondaHP@redline
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71 duster, came with a slant six but now has a junkyard 360 in it

When I dropped the 360 in it almost a decade ago in probably put a new alternator in there

A few days ago while driving my radio cut out and my oil pressure gauge went dead

I've since notice when this happens the amp meter also pegs past +40

At Idlw it sits close to dead center but as soon as it gets a few rpms on her the amps shoot way up...what's going on here ?

20251001_150535.jpg


20251001_150416.jpg


20251001_150258.jpg
 
First, disconnect the regulator and see if it stops. Next check and be CERTAIN that the VR is actually grounded. Don't just look at it. Clean the firewall behind it, around the screw holes, and clean the VR around the screw holes. Use star lock washers. If the charging stopped when you unplugged the VR, and if cleaning the mounting does not help, then replace the VR

If the charge does NOT stop with the VR unplugged, either the green wire from the VR to the alternator is shorted, or the brush holder connected to the green wire is shorted to the alternator case. In rare cases, the rotor winding itself becomes grounded.

DO NOT DRIVE it in this condition. Unless you unplug the VR and drive it with no charge
 
I won't even own an A body that hasn't had the ammeter bypassed. I don't trust em.

Get a thermal camera, stat.
 
67Dart273 said:
First, disconnect the regulator and see if it stops. Next check and be CERTAIN that the VR is actually grounded. Don't just look at it. Clean the firewall behind it, around the screw holes, and clean the VR around the screw holes. Use star lock washers. If the charging stopped when you unplugged the VR, and if cleaning the mounting does not help, then replace the VR

If the charge does NOT stop with the VR unplugged, either the green wire from the VR to the alternator is shorted, or the brush holder connected to the green wire is shorted to the alternator case. In rare cases, the rotor winding itself becomes grounded.

DO NOT DRIVE it in this condition. Unless you unplug the VR and drive it with no charge
Click to expand...


Ok, so this is what I found

1, with the VR disconnect the amp meter sits stoic

2, with the VR connected and an extra ground wire ran to the hot side of the battery the amp meter will sit stoic as well, but the engine will keep running with the ignition off

3, I'm an idiot

4, with the VR connected and an extra ground wire ran to the negative side of the battery, the amp meter will show just past center at idle and between the 1st and 2nd white mark past the middle when revving

Not showing anything crazy at that point

I haven't had a chance to drive it yet but I think the ground issue was a likely culprit , so I went ahead and cleaned everything and reinstalled it
Ill report back once I get some miles on her again

jos51700 said:
I won't even own an A body that hasn't had the ammeter bypassed. I don't trust em.

Get a thermal camera, stat.
Click to expand...

I prolly should but I don't like the idea of a 'dead' gauge

What would the camera tell me ?
 
diymirage said:
Ok, so this is what I found

1, with the VR disconnect the amp meter sits stoic

2, with the VR connected and an extra ground wire ran to the hot side of the battery the amp meter will sit stoic as well, but the engine will keep running with the ignition off

3, I'm an idiot

4, with the VR connected and an extra ground wire ran to the negative side of the battery, the amp meter will show just past center at idle and between the 1st and 2nd white mark past the middle when revving

Not showing anything crazy at that point

I haven't had a chance to drive it yet but I think the ground issue was a likely culprit , so I went ahead and cleaned everything and reinstalled it
Ill report back once I get some miles on her again



I prolly should but I don't like the idea of a 'dead' gauge

What would the camera tell me ?
Click to expand...
It sure sounds like it became ungrounded.....a common issue over time. The thermal camera is a really good idea. It will show you where heat buildup is.
 
diymirage said:
Ok, so this is what I found

1, with the VR disconnect the amp meter sits stoic

2, with the VR connected and an extra ground wire ran to the hot side of the battery the amp meter will sit stoic as well, but the engine will keep running with the ignition off

3, I'm an idiot

4, with the VR connected and an extra ground wire ran to the negative side of the battery, the amp meter will show just past center at idle and between the 1st and 2nd white mark past the middle when revving

Not showing anything crazy at that point

I haven't had a chance to drive it yet but I think the ground issue was a likely culprit , so I went ahead and cleaned everything and reinstalled it
Ill report back once I get some miles on her again



I prolly should but I don't like the idea of a 'dead' gauge

What would the camera tell me ?
Click to expand...

It will show any hot spots in any wire, and it will show you any circuits that are running, overloaded, etc.

I have used them to find key-off draws, before. Plus overloaded breakers, and poor junctions in home wiring.

I have one on my phone, it's a handy thing to have. This is my bathroom fan, you can see the GFCI outlet (which draw power all the time, even when nothing is plugged in). The cord is not showing any heat because I just turned it on, but over time it will warm up, too. It's not drawing much power so it takes awhile.
flir_20251002T045759.jpg
 
The ammeter is showing something is wrong. It was cheaper for Chrysler to install than a thermal camera.
There's only a handful of reasons why a battery would draw that much current, especially in the circumstances described.
 
I bought a thermal camera off Amazon. It is really amazing for trouble shooting things. You can easily find bad electrical connections and stuff like air leaks in your house.
 

Here is the link to explanation and instructions. My neighbor had his wiring melt down and burn in a 74 Duster because of the amp gauge wiring.
 
I'm prob on your ignore list but hate to see you destroy your car.
diymirage said:
1, with the VR disconnect the amp meter sits stoic
Click to expand...
It should show discharge. If not something is wired wrong.
diymirage said:
2, with the VR connected and an extra ground wire ran to the hot side of the battery the amp meter will sit stoic as well, but the engine will keep running with the ignition off
Click to expand...
Connecting ground to the hot side of the battery is good way to create heat, lots of it.
The whole reason for a fusible link in the battery feed is to prevent the battery positive from grounding.
diymirage said:
3, I'm an idiot
Click to expand...
LOL. But no reason you have to be ignorant about how this works. Lots of posts on how the charging system works
diymirage said:
4, with the VR connected and an extra ground wire ran to the negative side of the battery, the amp meter will show just past center at idle and between the 1st and 2nd white mark past the middle when revving
Click to expand...
So problem appears to still be there.

Do you have voltmeter? Clip the red lead to the battery positive and the black lead to a battery ground.
Rev the engine slowly while watching the voltmeter. If the amps to the battery go up with increasing voltage, then the problem is lack of regulation. Three possibilities then: 1. The alternator brush or green field wire is grounding. 2. Regulator has failed. 3. regulator is getting wrong information (reading low voltage or no voltage on its sense terminal).

Why the battery draws more charge with increasing voltage just discussed last night here

How the regulator works
Identifying Chrysler Alternators (1960-1976)
 
Last edited:
wjajr

Post in thread 'Install volt meter in place of ammeter wiring question'

67Dart273:
I spent the afternoon surfing automotive wiring methods, and found MAD’s site as well as the diagram illustrating parallel conductors passing through bulkhead connector a continuous conductors, and amp gage removed from circuit.

I have two concerns with this method: one, parallel conductors without proper over current protection is not acceptable; two, removing the capability of disconnecting engine compartment harness from under dash harness is cumbersome if repairs to either require disconnection by running from engine compartment to factory splice continuous conductor ...

Post #7 has the links to MadElectrical
 
so, since were discussing amp meter bypasses, i seen one guy on youtube who simply ran a heavy gauge wire from the charge stud on the alternator straight to the battery (i guess this counts as one of the "big three" of general automotive electrical upgrades)
he left the amp meter in place and wired up as usual, claiming it is now no longer carrying all the current, since current takes the path of least resistance and simply travel through the larger wire straight to the battery, does this make sense?
 
You'll do what you want of course, but there's a video in the link which explains the drawbacks to the bypasses and shunts.
(apologies for the link format, some sort of software glitch @Joeychgo is aware of.)

Mattax

Post in thread 'Ammeter bypass turning over alternator'

I've posted this a bunch of times because this crazy magic bullet type advice can be very destructive. While there have been times when an ammeter has failed, in those instances there is a cause - usually some sort of environmental damage (water leak), or excessive charging rate, or modifications (add ons like a winch, EFI and electric fans and pumps, or high watt stereo amplifier).

In the meantime, lots of innocent people hack up their car's wiring and cause real damage.

:soapbox:
We've had at least two people post that when they, or their dad, with many years working service at...
  • Agree

Mattax

Post in thread 'Darn Electrical Bugs'

Mattax said:
First, learn how the system is supposed to work.
Click to expand...
The car has two power sources; battery and alternator.
Each has a wire that connects to the main circuits at a welded junction.
This junction is hidden in the harness.
Power goes to the junction and then can continue on. All of the wires attached at this junction are attached to the battery positive, so they are always hot.
The main feeds go to:
1. Fuses that are always hot. (wire Q3)
2. Headlight switch for headlights (wire L1)
3. Key switch. (wire J1)

1748781085402.png

Power to the horn is an exception. In '66 its connected at...

67CBodyGuy

Post in thread 'MAD ammeter bypass question'

I believe this was the first video posted about it:



I recommend that people have a look at this thread:

Ammeter bypass

Is this something that is important to do if everything in the car is factory stock? I've heard it should be done if you upgrade the alternator and start pulling a lot more amps than the factory wiring was designed for. I'm guessing the only reason they catch fire is because the connections on...
www.forcbodiesonly.com
  • Thanks!
 
Joeychgo said:
what glitch? All looks good to me? PM me please
Click to expand...
Some of these links we post, and copied right out of the address box, get renamed to some silly thing like "pardon our intrusion" or some similar
 

Joeychgo said:
what glitch? All looks good to me? PM me please
Click to expand...
Instead of the link showing as URL or snippet, it shows the entire post. I find it very hard to read the person's post when there are one or more posts showing within it.
My view is that the reason for supplying a link is a reference for those who want to go read more.
In contrast to incorporate something in to a post, thats what cutting and pasting is for.
Just my perspective as a user.

I mentioned it in the website thread so figured you were aware of this new quirk.
Mattax

Post in thread 'Hey Joey'

Here's a quirk with the latest upgrade. When links to another post or thread are pasted in, the software codes it as "embedded". The result is a large post within the normal post instead of a simple link.
Like this

instead of this
Holley/Demon Carb stumble
 
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