Alternator Gauge needle leaning to the "PLUS" side?

[Mike's Dart]

Went to leave the house (engine warm) got to the end of the driveway and the engine stopped like I had turned the key off? Headlights were on, defroster fan on high and wipers on. Turned everything off and turned her over and took right off. Drove around the driveway all is well. Drove 10 miles to town and engine seemed to be missing while setting at a red light. I turned the headlights off and the defroster off and the engine straightened out? Noticed the needle on the alternator gauge leaning toward the plus side. Need a new battery or do I have an alternator getting ready to die? Guess I'll drive the Corolla to work tomorrow.

 

[crackedback]

Check the bulkhead connector for melting where the black alternator wire passes through. Also check the ammeter connections.

 

[Mattax]

Noticed the needle on the alternator gauge leaning toward the plus side. Need a new battery or do I have an alternator getting ready to die?

I'm going to hazard more possibly the latter. Maybe one diode.
Clearly the battery was accepting charge when you turned the accessories off. Preseumably then the alternator was not keeping everything running with the accessories on. Was the battery showing discharge when the lights were on?
That's not a definative. Rob's suggestion is also good. Check that alternator output wire at each connection, and the battery positive and ground while your at it.

crib sheet version of power flow:
Understanding Charging Systems with Ammeter:

 

[RustyRatRod]

My bet is either what Rob (crackedback) talked about, or a bad battery. If the battery is going out, the alternator will charge its guts out trying to keep up.

 

[Mike's Dart]

I'm going to hazard more possibly the latter. Maybe one diode.
Clearly the battery was accepting charge when you turned the accessories off. Preseumably then the alternator was not keeping everything running with the accessories on. Was the battery showing discharge when the lights were on?
That's not a definative. Rob's suggestion is also good. Check that alternator output wire at each connection, and the battery positive and ground while your at it.

crib sheet version of power flow:
Understanding Charging Systems with Ammeter:

Thanks! Yes, the battery was showing charge with the light on (Alternator needle to +).

 

[Mike's Dart]

Check the bulkhead connector for melting where the black alternator wire passes through. Also check the ammeter connections.

Will do! Thank you! At least she waited till the weekend! LOL I'll get after this first thing Sat morning!

 

[Mattax]

Thanks! Yes, the battery was showing charge with the light on (Alternator needle to +).

If the battery is charging with the lights and heater fan on, then the alternator is probably fine.
The question to answer is: why didn't the battery charge up and stay charged after starting?
Answer is going to be Battery itself, inconsistant connection somewhere; or partial short to ground (such as chafed wires touching body).
If its the last, at least you know from the ammeter which side to start looking.

A couple other thing to check; one is voltage while running. If the VR isn't controlling voltage, then the alternator will be at 15 to 17 Volts depending on rpm. With that much voltage, the battery may continue to try to charge (boiling the acid).
The other is to note whether the lights dimmed at idle or conditions. This is a clue on how well the alternator is working and delivering electricity to the system. The ammeter doesn't tell you that. (see crib sheet)

 

[RedFish]

I'll guess bad battery too. Seen it before. In one case brake lights alone would cause engine stumble. Headlights would shut it down.