Battery light and overheating

[NeMiZiS]

Ok well I had to replace my alternator about 3 months ago.
I just got a cheap o'reilly's alternator and reused the same belt.
I haven't had any issues until last Friday.
After about 20-25 minutes of driving the battery light is coming on.
Then my temp gauge starts climbing, while I have a load on the engine.
As soon as I put it in neutral, the temp will immediately drop back to normal operating temp.WTF
I checked the temps on the block and the head with my infrared thermometer, nothing above 220(F).
This is after driving for 30 minutes or so.
I checked the battery voltage while starting, 12.60 drops to 10.60 during start up.
During idle the lowest voltage is 14.10 volts hot or cold and it doesn't fluctuate if I rev the motor.
I'm going to have my battery tested at the auto parts store.
How could the battery light coming on have anything to do with the temp gauge climbing?
I've never had an issue with the temp or the gauge before.
Just looking for some input before I spend any money.

 

[turbodude]

Interesting... Could possibly be the voltage regulator is faulty. perhaps it is causing spikes here and there which throws your batt light on. I don't see though how the temp gauge should be effected in all of this though

 

[NeMiZiS]

How do I test the voltage regulator?
Looks like it is inside the ECU on a 420A.
http://www.dsmtuners.com/forums/420a-engine-management/296266-ecu-houses-voltage-regulator-420a.html

 

[NeMiZiS]

Well now my check engine light and battery light are on, as soon as I start the car.
Checked the voltage at the battery at idle and now it is 18.00V+
So I'm sure the regulator in the ECU is bad.
I'm pretty sure the strange temp gauge readings, have something to do with the ECU going out.
I'm going to finally get that Howell AFX ECU I've been wanting.

 

[turbodude]

Wow, 18V is pretty dang high, even if you were flooring it let alone at idle, . Yeah, i'm not sure how to check the voltage regulator in your case but it definitely sounds like its the problem. Hey, look at the bright side, you get something you've wanted and you have a high probability chance to fix the problem all in one!

 

[Slo2gen]

I've seen other guys have the voltage regulator go out and end up using an external regulator and cutting the stock one loose. You can use the same regulator from mid-late 80's chrylser cars(the same one we use with Megasquirt) and it solve the problem.

 

[CODE4]

Well now my check engine light and battery light are on, as soon as I start the car.
Checked the voltage at the battery at idle and now it is 18.00V+
So I'm sure the regulator in the ECU is bad.
I'm pretty sure the strange temp gauge readings, have something to do with the ECU going out.
I'm going to finally get that Howell AFX ECU I've been wanting.

The Cluster gauge has its own sender and is independent of the ECU.

 

[NeMiZiS]

I've seen other guys have the voltage regulator go out and end up using an external regulator and cutting the stock one loose. You can use the same regulator from mid-late 80's chrylser cars(the same one we use with Megasquirt) and it solve the problem.

I know that an external regulator is an option.
Since I'm in Alaska I'm about to get my PFD, so I'll have the extra money to spring for the Howell ECU.

The Cluster gauge has its own sender and is independent of the ECU.

Yea I know, if I still have faulty temp gauge readings after I get the new ECU.
I'll just get a new sensor.

 

[bullettdsm]

Yup, sounds like voltage regulator BUT, what are you going to use for a core for the AFX?

MB

 

[NeMiZiS]

Well I was going to send them in my ECU.
Am I going to need another good ECU?
I thought the core I'm sending in, was just going to get rebuilt.
I just called Howell and they said if the regulator is bad, then the core is no good!
Time for a WTB add

 

[CODE4]

Yea I know, if I still have faulty temp gauge readings after I get the new ECU.
I'll just get a new sensor.

You know the sender can be bought new for $5-$10 right?

 

[bullettdsm]

Well I was going to send them in my ECU.
Am I going to need another good ECU?
I thought the core I'm sending in, was just going to get rebuilt.
I just called Howell and they said if the regulator is bad, then the core is no good!
Time for a WTB add

That's what I was getting at........

MB

 

[NeMiZiS]

Thanks bullett!
I would have just sent them my bad ecu otherwise!
Since my 2g has a 94 build date, do I have to get a ecu from another early 95?