Alternator or regulator or?

[vancamp]

Any guess as to this problem when car is running, hook meter up to battery and it fluctuates between approx. 11.5 amps and 13.5, I am going to take alternator off and have it checked in the next few days just curious what the probable cause is.

[John_Kunkel]

Year?

[mopar_nut_440_6]

Is that amps or volts? If it is volts it is likely the voltage regulator but I would recommend checking your belt and pulley as when they slip you often see  readings like that.

[Nacho-RT74]

status of ammeter ?

[vancamp]

Year?

69 and I misspoke volts not amps, and ammeter has not been bypassed YET but acts odd as well (back and forth) I would have never thought the belt could be the problem, learn something new everyday, I am going to start checking and see what it is.

[Nacho-RT74]

http://www.dodgecharger.com/forum/index.php/topic,33574.0.html

If it was just the ammeter acting like that, I could say you have loosen terminals on the line, BUT voltage shouldn't vary even if you have poor contact quality, because volts are able to be read even for JUST ONE HAIR. ( depending also on the load, given by ammeters )

However, could affect some too, on that.

I would guess some bad working inside alt... some alternate short while spinning. Damaged brushes or track on rotor

[vancamp]

well I took the alternator off and had it tested and it was perfect, put it back on and took the cover off the regulator and a friend put a meter on it while it was running and would be normal one minute and then it would fluctuate between 11 and 19 volts when it hit 19 the lights brightened up and the ammeter gauge pegged out.

[mopar_nut_440_6]

well I took the alternator off and had it tested and it was perfect, put it back on and took the cover off the regulator and a friend put a meter on it while it was running and would be normal one minute and then it would fluctuate between 11 and 19 volts when it hit 19 the lights brightened up and the ammeter gauge pegged out.

Yes, it sounded like a regulator problem! That is nice as they are less money than an alternator and easier to change!

[Nacho-RT74]

well... regulator problem is not necesarry.

I have a test in mind... is your alternator a single field alt, mechanical regulator ?

if it does, feed the wired brush with 12 volts from batt. You can unplug regulator and join both wires if wished to get the constant positive from ign switch, will be similar than feed from batt.

If is dual field:

Feed the brush you have with green wire ( what is negative on double field setup ) with constant ground, simply grounding that brush. Blue wire on the other brush is constant positive.

what we are making with this is bypassing regulator, and will get max output from alt.

check if you have same irregular reading

make it at idle.

[John_Kunkel]

If it's the original '69 alternator and regulator, hook the positve lead of a voltmeter to the FLD terminal on the regulator and the negative lead to a good ground. Run the engine and observe the meter reading, if the FLD meter voltage goes up at the same time the system voltage goes up the problem is the regulator.

If the voltage at the FLD terminal remains the same or drops when the system voltage goes up the alternator is faulty.

[vancamp]

If it's the original '69 alternator and regulator, hook the positve lead of a voltmeter to the FLD terminal on the regulator and the negative lead to a good ground. Run the engine and observe the meter reading, if the FLD meter voltage goes up at the same time the system voltage goes up the problem is the regulator.

If the voltage at the FLD terminal remains the same or drops when the system voltage goes up the alternator is faulty.

we did this and determined it to be the regulator, I put one on today and the it quit fluctuating and the the gauge read perfectly, turned on headlights and had a slight drop on gauge, lights off went right back to normal.

[Nacho-RT74]

great