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Fluctuating ammeter with turn signal and brake operation.

hunt2elk

hunt2elk

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Every wire and electrical control on my 69 Charger has been replaced or rebuilt. Not sure if this is a issue, but I have never seen quite as much ammeter needle movement as I am having with this car. Everything works fine, but at idle the needle will bounce up to charge when the brake pedal is pushed and does the same every time a turn signal lights up - it drops back down immediately. Can an ammeter just be overly sensitive? The service manual says excessive resistance in the regulator wiring circuit will cause fluctuation in the ammeter. So I did the test by the book by measuring the voltage from the positive side of the battery to the field side of the regulator with the coil unhooked. If the reading is over .55 volts, this indicates high resistance. I got 1.1v. They then say to backtrack to the battery until you find a sudden voltage drop. On the ign side of the regulator the voltage is .1v. That is more what they are looking for. I am using a solid state regulator and even tried another new one with the same results. I'm thinking the voltage drops would have been different with an original style regulator, so maybe this is all normal? The ammeter has been restored by Redline and I have greased and rechecked all the wiring connections. I should mention that I also installed a Mopar electronic conversion kit. Anybody ever dealt with something like this before?
 
This is way tmi for me. I disconnected mine to prevent a fire. Put in the "characteristic file maybe? My 09 Challenger has similar hints on charging while not as pronounced. Didn't figure it out in 40 years.
 
You sound like you are getting a voltage drop from your battery to your in car electronics in the dash
so the regulator is seeing a voltage drop and is trying to raise it so the amp gauge jumps
with your 4 way flasher on and using an analog volt meter so you can see the voltage bounce follow your connections till you find the bad one or the wire that is to light
 
Hmmmmm... the following statement does not make sense: "On the ign side of the regulator the voltage is .1v. " Can you clarify more? If this is to the dark blue wire to the regulator, then it should be very close to battery voltage.

Is this a stock wired '69, or possibly a late '69 production? The first question is if the alternator has 2 small wires on the back or just one. If 2, then you have the '70 and later 2 wire field system. TNx..
 
To me that looked like the voltage difference or drop pos to pos if you put an analog volt meter with flasher on you will see the needle bounce
and that is what will cause the voltage reg to ask for more then less etc so needle bounces
 
Dennis H said:
This is way tmi for me. I disconnected mine to prevent a fire. Put in the "characteristic file maybe? My 09 Challenger has similar hints on charging while not as pronounced. Didn't figure it out in 40 years.
Click to expand...

Your 2009 does not operate anywhere near a 69 charger. The cluster controls the guage operation based on bussed inputs from the pcm. its normal for the 69 guage to fluctuate like that at idle when the alternator is basically doing nothing at that low an rpm.
 
Ok guys, here is what I was trying to explain. These pics show the test in the service manual. I just rechecked the voltages and have 1.1 on the field side of the regulator and .15 on the ign side. Just for shits and giggles I did the same test on my 69 RR which I have the same style regulator. On that car, I have 1.45 on the field, and .58 on the ign side. The Road Runner doesn't have any issues with the ammeter needle, so now I am even more confused.

P6190004.jpgP6190005.jpg
 
Pops1967GTX said:
More often its the VR,,,,I would check VR for a good ground.... Remove, sand,clean area & retighten .....
Click to expand...

That's what I was hoping Pops. I ran a separate ground jumper from the reg to the block and even tried another new regulator - still does the exact same thing. I should also mention that it also happens when I put the car in reverse and the backup light comes on when idling.

- - - Updated - - -

Pops1967GTX said:
http://www.imperialclub.com/Repair/Lit/Master/256/cover.htm



http://www.imperialclub.com/Repair/Lit/Master/259/Cover.htm
Click to expand...

I wouldn't mind having a copy of these in my garage.
 
hunt2elk said:
That's what I was hoping Pops. I ran a separate ground jumper from the reg to the block and even tried another new regulator - still does the exact same thing. I should also mention that it also happens when I put the car in reverse and the backup light comes on when idling.

- - - Updated - - -



I wouldn't mind having a copy of these in my garage.
Click to expand...

They can be downloaded & printed.... It seem when you put a load on the system it happpens more...I would bench test the alternator.. Possible bad diode, bushes.....
 
Pops1967GTX said:
They can be downloaded & printed.... It seem when you put a load on the system it happpens more...I would bench test the alternator.. Possible bad diode, bushes.....
Click to expand...

I was thinking that at first too, until I flipped on the hazards with the car off. Same needle bouncing as when idling.

- - - Updated - - -

nm9stheham said:
Is this a stock wired '69, or possibly a late '69 production? The first question is if the alternator has 2 small wires on the back or just one. If 2, then you have the '70 and later 2 wire field system. TNx..
Click to expand...

It is a stock 69 setup with the single field alternator. The only deviation is when I added the Mopar electronic conversion kit and an modern voltage regulator with electronic internals.
 
In the tests that you did, the voltage difference between the battery + and the field will depend on the resistance build up in the ignition circuit AND the voltage drop in the regulator. If you have a newer solid state regulator for this, then the voltage drop is different than across the contacts inside of the original relay style of regulator. The relay contact voltage drop wil be very low, but the voltage drop across the outpot transistor in the solid state regulator can be .5 to 1v, even with very low current flow. Soooo, I would not worry so much over the readings per that original test procedure.

(BTW with a poor VR ground, you would not tend to have this particular issue.)

It sounds like the alternator is charging fine. One factor in the ammeter reading is where the current is coming from ; it will come from both the battery and from the alternator. If the battery is weaker or the battery circuit connections into the car are poorer, then most of the current will come from the alternator and show up on the meter. This would happen at idle and at higher RPM's too. Is the battery old or are the battery connections dirty (including the ground lead). And is there a ground from battery - to the body directly in the RR and not in the Charger?

And..... now for the dumb things......check your brake light bulbs and make sure they are the right types.....and are oriented properly and not reversed. It could be a simple difference in the type of bulb or the number of bulbs (does the Charger have more brake light bulbs ???)....

Edit to ask: What is the battery voltage at fast idle for both cars, with the batteries well charged?
 
nm9stheham said:
Is the battery old or are the battery connections dirty (including the ground lead). And is there a ground from battery - to the body directly in the RR and not in the Charger?

And..... now for the dumb things......check your brake light bulbs and make sure they are the right types.....and are oriented properly and not reversed. It could be a simple difference in the type of bulb or the number of bulbs (does the Charger have more brake light bulbs ???)....

Edit to ask: What is the battery voltage at fast idle for both cars, with the batteries well charged?
Click to expand...

The battery and pos/neg cables are new, no corrosion anywhere. The Charger does have 4 more brake lights than the RR. I'll have to check the battery voltage on a fast idle this weekend.
 
OK, and while you are in there, see if the large, dark blue wire that goes from the large terminal on the starter relay to terminal N on the bulkhead is a fusible link or has a section of fusible link spliced into it; if so, examine the fusible link for any weak spots that could indicate localized heating and thus high resistance spots. (If all new, then this is probably not an issue....) And check the ignition switch area for any warmth with things on. It probably is not any issue since you got such a low BAT+ to ign side fo VR voltage drop in your tests.


Anf before you start the car for the high idle voltage test, measure the battery voltage.Maek sure the car has been driven for a whiel before you do the fast idle voltage test, to be sure the nattery is well charger. Your ammeter should be a good indicator of this; if it is showing a good charge with the engine running at fast idle and no other electrical loads turned on, then you can be sure it is charging the battery still and you should wait 'til the ammeter drops to near 0 charge.

Kinda sounds to me like it is just the higher load with the larger number of brake lights.....which I beleive was an earlier poster's conclusion.
 
Also remember the ammeter on your car is in series with the full electrical system. Around 1973 Mopar went to shunt type ammeters which use a shunt across the ammeter to carry 90% of the load and on that setup the ammeter hardly ever moves. But on the older ammeter setup like yous the ammeter needle will move alot and will flucuate even when you use the turn signals at idle which is normal for that system. Have you checked the charging system output and voltage to make sure its normal ? Ron
 
383man said:
Also remember the ammeter on your car is in series with the full electrical system. Around 1973 Mopar went to shunt type ammeters which use a shunt across the ammeter to carry 90% of the load and on that setup the ammeter hardly ever moves. But on the older ammeter setup like yous the ammeter needle will move alot and will flucuate even when you use the turn signals at idle which is normal for that system. Have you checked the charging system output and voltage to make sure its normal ? Ron
Click to expand...

I'm hoping it is normal, but haven't seen one bounce around nearly as much as this one does. I swapped alternators and voltage regulators from my Road Runner to the Charger with no change. Took apart, checked, and regreased all the terminals in the fuse block, and rechecked all the connections under the hood. I'll probably do the same on the ignition switch and bulkhead connector next. I also have to check all the bulbs although I don't think that is a problem because they all work.
 
I would consider it pretty normal for a 60's Mopar system. The early systems had ammeters and not voltmeters and when measuring amps it doesn't take much load to make the needle bounce especially when the load is run through a flasher to turn it on and off at a pretty rapid rate. The system doesn't recover fast enough. With the engine running switch on your blower. I'll bet the needle will take a dive and then stabilize when the load catches up with the output. tmm
 
Replace the amp meter with a voltage meter or by pass the system.... go to mad electrical on the web.... the amp meter system is #1 fire starter in mopar stuff. The operation of the turn signal showing a huge movement on the meter = the sodder has come loose and any fiddling you do will only loosen it up more.... you can have the amp gauge 're sodderd but it's still a flawed system that should be eliminated...
 
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