Alternator - Voltage regulator problem

chemeng · Jul 30, 2007

Hi Everyone,

Just replaced the alternator on my '65 stang and had some problems coming back from the cruise Saturday night. Four times on the way home all the lights would go out, the car would stumble, then the lights would come back on and the car would run fine again. By all lights I mean headlights and dash lights too. I replaced the voltage regulator 3 years ago and thought it would be OK. Does it make a difference that the NAPA alternator I bought is internally regulated but I still have the voltage regulator connected? Should I just replace the voltage regulator? The replacement unit was an AutoZone cheapie, only paid 12 bucks for it. Where could I get a good quality replacement?

Thanks, MikeR

Rusty67 · Jul 30, 2007

What alternator are you running now ? If you have an internally regulated alternator, there should be no need to keep the regulator box.

chemeng · Jul 30, 2007

Alternator

Just checked the NAPA website. It says the alternator is externally regulated, see the last item:

Item#: RAY133014
Price: $55.49
Core: $5.50

Attributes:
Features & Benefits:Bearings - 100% New
Premium Quality
Features & Benefits:Completely Remanufactured With The Most New Top Quality Parts Available
Features & Benefits:Computer Tested Under Loaded
On-Car Simulated Conditions
Features & Benefits:Electronics - Heavy Duty for Longer Service Life
Features & Benefits - 2:Brushes - 100% New
Premium Quality
Amp Rating:55-61 Amp
Type of Pulley:1 Groove
Type of Regulator:External

Does the lights going on and off indicate a regulator problem? It ran fine before the alternator change, old alternator was running around 11-12 amps at idle, new one runs at 14 amps.

Thanks, MikeR

70dvr · Jul 30, 2007

When I still had the original charging system. My regulator stopped working about 15 mile from home. I had an after market Amp. meter so I knew I had no charging system.
My lights dimmed a bit, but did not go out.
Not sure what might be wrong, but it sounds like you may have a bad connection somewhere.

mustangmike6996 · Jul 30, 2007

check for the voltage drop in the system and also check for the system charging voltage.. no more than 0.03v positive drop and 0.01v negative drop. and with a DMM on the battery terminal post there should be 13.5-1.5 volts when the car is running at all times.

Az Pete · Jul 30, 2007

Sounds the me like you may have problems with the headlight switch. They will get hot and lose the connection, cool off and work again. I would say to replace it. If the battery is staying charged to a proper level, the alt. and reg. are most likely working.

pabear89 · Jul 30, 2007

chemeng said:
Hi Everyone,

I replaced the voltage regulator 3 years ago and thought it would be OK. Does it make a difference that the NAPA alternator I bought is "internally regulated "but I still have the voltage regulator connected?

Thanks, MikeR

What's wrong with this statment.....

chemeng · Jul 31, 2007

NAPA alternator is not internally regulated

I goofed, it isn't internally regulated. The alternator I ended up buying is externally regulated. Thought about the headlight switch too. Replaced it 3 years ago when I replaced the voltage regulator. Doesn't mean a lot though, it was a repop switch made in China, all this crap we're buying from there is going to kill us one day.

Thanks, MikeR

Rusty67 · Jul 31, 2007

You should install relays for the head lights anyways. Someone did a write up on this. Use the search, should be easy to find.

First things first, figure out if you have a charging problem or not.

chemeng · Jul 31, 2007

Charging 14 amps at idle

Ok, so it runs and charges OK with the lights off. Problem is when the lights are on, and at idle. No problems when the car is cruising or the lights are off. Haven't tried running it at night with the lights and fog lights on. So I'm back to the voltage regulator or headlight switch.

Thanks, MikeR

Rusty67 · Jul 31, 2007

You don't need to run it at night to check the voltage with the lights on. Just turn the lights on then check the voltage.

chemeng · Jul 31, 2007

Voltage drops

Voltage drops off to 12.5 amps at idle when I have the headlights and foglamps on. Foglamps by themselves drop me to 13.5, then another amp falls off with the addition of the headlights. Is this normal?

Thanks, MikeR

Rusty67 · Jul 31, 2007

I don't think the problem is in your charging system.

Tim65GT · Aug 1, 2007

I don't think the problem is in your charging system.

+1

At idle, the lights will likely draw the system down under 13 volts. If you tap the throttle, the voltage should jump back to above 13. If you sit in traffic at night in the rain, you might be in trouble. (Headlights, brake lights, wipers, fan for defogger....)

I have that problem now, so I throw it in neutral and keep the revs about 1000-1200.

Do you have the newer style halogen lights, or still the old ones? If you have the halogens, you should put a set of relays in. I have one for Low beam, one for high beam, and one for the fog lamps.

chemeng · Aug 1, 2007

Halogen lights

Yes, I've upgraded to newer halogen lights. Looks like a set of relays are in my future. Does anyone have a link to the writeup or the subject line header? I did a search yesterday on "headlight relays" and came up with 9 pages.

Thanks, MikeR

Alternator - Voltage regulator problem

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