ALT Gauge Bouncing 1/2 way to C quits at high RPM

[coop]

I think I am having a issues with my voltage reg. 1970 F250 390 Camper Special with ALT gauge. Replaced the Alternator, bearings were going, the problem was there with the old alternator it goes as follows: Turn the ignition on the gauge slightly moves to A and you hear a click from the Voltage regulator, start the engine the gauge slightly moves to the C then it starts bouncing 1/2 way to C the engine seems to have a miss along with it. Get the RPM up to around 2000 and it Quits and is slightly past the center towards C like it should be. if you let off the throttle and coast it will do the same thing start bouncing. I checked the voltage at the battery at idle and it fluctuated between 14.7 to 15.7 to 15.9 volts I believe it was going with gauge I couldn't watch the gauge at the same time with the engine off the battery voltage is a little over 13V. The voltage regulator has been replaced awhile ago the Condenser is the original. Also if you are driving at night the lights dim and pulse at idle and when the bouncing stops they get bright seems brighter than normal. There are only three wires to the ALT and I believe they are hooked up properly. Like I said the same problem was the with the old ALT. All is stock any input would be appreciated.

[fordman]

i think that sounds like it is working very good to me. the headlight thing sounds normal. i coul dbe wrong though. usually most guages in these trucks never move. you must have gotten lucky and found a truck with a good wokring system. but i could be wrong. i think if i remember what i read. that the guage shows the differences in the battery power to the charging rate. so maybe its the battery playing games with you.

[coop]

I don't know the battery is brand new also.

[fordman]

what i am thinking by everything going up and down is that it sounds like it is running straight off of the alternator. but it may be the way it is suppose to run. someone else will come in and either confirm what i have said or tell you i dont know what i'm talking about one of the two.

[bluef250]

Sounds like a bad rectifier in the alternator.

[seattle67]

Your alt gauge and voltage jumping around like that could be due to a loose connection on the alternator field circuit, or the regulator could be going bad. Those voltage readings up in the 15+vdc is a concern. The voltage limiter in the regulator should be factory set to keep the voltage under 14.7vdc.

[coop]

I was thinking the same thing that the volt reg might be going out. I just came back from driving it and while the needle was in the middle while cruising I turned on the head lights and it started bouncing that was at cruising speed. who do you suggest purchasing a regulator from? It seems everything is made in China and doesn't last worth a darn. thanks

[fordman]

do you want an original adjustable one. if soihave a few of htem. they are used and have been tested to make sure they are good.

[coop]

I conquered that gauge! It was the voltage regulator. I couldnt wait I purchased a Duralast from Auto zone $16.00 it is a electronic model. Installed it and the gauge barely budged and the charging voltage right on the money at 14.4 volts. It's great when something goes right thanks for everyone's input.

[fordman]

this must be a good day fo reveryone then. i finally caught that lady at home and fixed her hotwater tank.