Amp meter fluctuation?

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74/6Dart

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Say, would anybody know if it is normal for the amp meter gauge to fluctuate rapidly during idle and even more so when the directionals are on?

When the rpms are raised this dosn't happen. Also the fluctuations are directly timed with the fluctuations of a rough idle problem I'm working on.

I don't know if the electrical is causing the rough idle or vice vesa. Any suggestions would help. :scratch:

Thanks!
 
To be sure the "electrical is not causing" the rough idle, simple yank one field wire off in order to disable the charging system, and if necessary, charge the battery

Then run a clip lead from the starter relay stud or other battery source directly to your ignition system. On an points or ECU system, this is the "key side" of the ballast, IE opposite side from the coil

IF the problem goes away, the charging system OR WIRING has something to do with the rough idle. No1 suspect is the BULKEAD CONNECTOR

Please read this article by MAD electrical:

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

It shows, whether you perform the modification or not, the pitfalls of Mopar wiring

This problem could be SEVERAL things

Bad bulkhead connector terminals.

break somewhere in the alternator charging wire and connections, including the BULKHEAD and the AMMETER, as well as the "IN HARNESS SPLICE"

Bad alternator, either worn or stuck/ damaged brushes, or other internal problems

Bad connections in the "igntion run" circuit, which ALSO supplies the regulator and field circuits

Bulkhead connector, ammeter circuit, igntion switch and its connections.


Some tests

Run a temporary wire either no10 OR LARGER, or maybe three or 4 no 14's in parallel directly from your alternator stud to the big stud on the start relay

The ammeter will NOT work, but measure with a voltmeter, observer your idle, and action of lights, heater, and see if this improved problem.

Hook a temporary wire no14 or so directly from starter relay stud to ignition system/ regulator and see if this makes a difference.

WIth key in "run", engine OFF, measure the voltage drop in the ignition suppy harness

To do this, hook one meter probe on the battery positive post, the other lead where your "dark blue" "ignition run" supply hooks, you can access this at the regulator "I" (ign) terminal or the "key side" of the ballast

What you are hoping for is a VERY low reading. Anything over .3V (3 TENTHS of a volt) means you have a poor connection in the igniton feed

The circuit path is battery -- fuse link -- bulkhead connector -- ammeter circuit -- ignition switch connector -- through the switch -- back out the switch connector -- back out the bulkhead (dark blue "run") to the regulator, the ign. system, and on 70/ later cars, the alternator field.
 
Unless your regulator has been changed, you still have the old points type voltage regulator. They are a coil and a set of points and work by turning on and turning off the alternator. Yes the amp gauge will fluctuate at idle and especially with the turn signals on. You should be able to see the needle move each time the flasher flashes. It is remotely possible that low voltage is causing a engine miss but not very likely. An engine miss will aggravate the amp needle jumping though. Without seeing it for myself, I would say it's a normal thing. tmm
 

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toolman,

I do have the new electronic (not mechanical) regulator and your discription of the symtoms are correct. so I'm if the regulator is the correct one for the car/or just bad (i've got the electronic IGN w/o points)

also 67D... the car seems to be set up with the high amp alt. and low amp alt. wiring fixes... meaning: the fusible link at the bulk head w/ a looks like clear passthrough and the inline fuse on the amp meter to alt. dk blue wire.

so it looks like based on the other posts that I have a lot to go over and dbl. ck.
 
Also, after reading the posts I think I'm really going to have to check charging circuit (etc.) wires on the pasenger side of the engine because they look very very crispy.

But, TMM is this gauge movement normal on all cars regardless?
 
Just the mechanical regulators. You may see the needle jump slightly with a electronic regulator but not as noticeable. As long as the system works and is providing enough electricity to run the system and charge the battery all is well.
tmm
 
You might not have much of a problem depending on how severe the fluctuation is. With a electronic regulator the amp gauge should be pretty steady. You need to test the system to make sure all is operating properly. 67Dart273 is very knowledgeable and he can get your charging system up to snuff. Old components, wiring, and connectors can cause problems for sure. Old technology doesn't help either. Do some checks and fixes and you'll be good to go. I should have looked closer at your name. 74 slant 6 cars should have electronics. My bad! LOL tmm
 
Put the meter on the battery, and check; then the alt. That should narrow it down to bad connection/crap amm or wire.
 
Hey guys,

Turns out after all the checks it ended up being 2 wires from ECU to distributor, 1 had 12ohms resistance and the other had 22 ohms resistance, they were pretty crispy (like coat hangers). So I changed them out and also found the choke linkage was sticking a little which was also driving down the idle from time to time, which was reflected in the ammeter. Now she moves only a tiny bit at idle with turn signal on, whick I think is probably normal. And the idle is ni........ce.

I thank you all for the really good info!
 
74/6Dart said:
also 67D... the car seems to be set up with the high amp alt. and low amp alt. wiring fixes... meaning: the fusible link at the bulk head w/ a looks like clear passthrough and the inline fuse on the amp meter to alt. dk blue wire.
Click to expand...

By the way 67Dart273 I was totally off on this, it turns out it's just the low amp wiring without the pass through fix. The little rubber insulators on the bulkhead connectors thru me off, I thought they were grommets, and read the wiring diagram wrong. Next time more :coffee: first!!!

Thanks for your help and knowledge!
 
I've had a lot of old Mopars over the years with this issue but it never really caused any problems other than the headlights surging at idle. Although this is an older post I'll add some info to help anyone else with the "Dancing amp meter gauge" First I'll tell you the set up. I had owned my 1966 Dodge D-100 for about a year with the original 225 and 3 on the tree, it had the "Dancing/twitching amp meter" from day one. At that point I updated to a 440 with Edelbrock heads and Intake, aluminum water pump and housing, a new Ron Davis aluminum radiator and a 4 speed. I rebuilt the original starter and alternator at Gen Star in Glendale and I had told Gary about the twitchy amp meter when I dropped them off. When I picked them up he said the alt had a loose stator plate and that could cause the twitchy needle.(?It's been a while but I think that's what he said?) BTW the engine compartment had been completely stripped and repainted too. So I fire up the all new engine and Waa Laa, the same twitchy needle. Now what? I've never had any damage from this issue before right? So when I have some extra time I'll take care of it. Fast forward a year and out of no where I start getting little specs of coolant on the engine and air cleaner. Where the hell is it coming from? Several weeks later and a lot of inspecting I finally get my answer. My expensive aluminum radiator has several tiny pin holes in it. WTH? continued....



Keyword: Electrolysis, Ammeter, Electrical system, Cooling system.
 
Part 2 So I suddenly remember what the guy at Ron Davis told me about checking for voltage in the coolant IMMEDIATELY after starting your car for the first time with the new aluminum radiator. Yep. I didn't follow that advice and it cost me dearly. So I bought a VOM (Volt/Ohm meter) and tested my system. With every electrical system on, headlights on high beam, heater blower on high, radio, etc I was reading 3 volts in the coolant! Yes THREE volts. I was also getting a 2-3 volt spike when the starter was engaged. In a stock cast iron engine with a brass/copper radiator it's not that much of an issue. But if there are aluminum components in the system it's a BIG issue. After a week of cleaning and upgrading grounds and cleaning the rusty clips in the fuse block I got it down to .3 volt. I was still getting a .8 volt spike when the starter was engaged but it was much better. The twitchy needle issue was still there though. I talked to Gary in between all this and he had given me many of the suggestions listed earlier in this thread. But he said one thing no one else had mentioned, the ignition switch. So I changed it out and BAM! No more twitchy needle and ZERO VOLTAGE in the coolant. All this time it was an other wise perfectly operating ignition switch. Many of the other things contributed to this problem, but the switch was the root cause. I hope this helps other people out there with this issue before they lose any expensive components like I did. Here are two very good links with knowledge and info about this problem. The first has a lot of knowledge info and the second has some great products to help fight this demon as well!!! Hope this helps!
http://www.sancarlosradiator.com/VoltageDrop/index.html
http://www.ve-labs.net/

Keyword: Electrolysis, Ammeter, Electrical system, Cooling system.
 
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