High revs = alt lights

[RTLarson]

http://img178.imageshack.us/img178/5600/altlightob1.jpg
When i hit about 4500 rpms, my alt light and my brake light come on. But when i turn the car off and restart it, they aren't on anymore. The volts don't change when i rev it up (spike or drop) but the light turns on and the volts drop slightly. I heavn't let it go long enough to see if the volts slowly drop (no alt output), i'm affraid the battery will go dead and i'll be stranded.

Backround;
When the shop had my car (FOR 16 DAYS) They left the door open and the battery went dead. They tried to sell me another one. Myine is less than a year old so i told them to go f*** themselves and jump the car. It charged right up and i haven't had a problem with it except for this.

My alt was rebuilt last christmas (lifetime warranty) and the battery was replaced last summer.

Another question:
When i got the car back, it started overheating again. They'd just put in a new radiator so i figured there was air in the system and there was, but when it was hot a lot of white smoke came out, it always did that when it got hot all those times. Did i toast my head gasket??? It doesn't do it anymore, but is it still screwed?

Thanks guys

[Tanya]

hmmm... overheating AND voltmeter light... check your alternator belt.

check oil, see if there's any water in the oil (milky) to see if you have BHG.

[RTLarson]

the oil's okay and the belt is new and tight. It was overheating because there was air in the system from when they put in the new radiator, i bleeded it and put in a little more water and it hasn't overheated since.

[Junkie]

I'm home bring it over.19th and Highland look for the Supras ;)

[Darrow]

the alt's VR most likely went by by. The Ecu is detecting an over voltage condition.

[Mone]

I've went through 3 alternators in a single year in mine. The lights came on each time when they quit, but they'd work some of the time. For me, they wouldn't work at idle, but at above 3000-3500rpms the alt would work. But I agree with Darrow about the Voltage Regulator. That's what quit on 2 of the 3 alts that failed for me.

[RTLarson]

I'm home bring it over.19th and Highland look for the Supras ;)
SHIT! I knew i should've stayed around the house a little longer! I left for everett without checking my msgs yesterday. I just got called into work, will be off around 2:30. I'll be in everett around 3:30ish, if your free today i'll stop by.

Thanks!

[Junkie]

Stop by,I'm bored as hell.Moving slow,but we can put the multi meter on the car,and check it out.You just have to deal with my Vicodin induced daze ;)

[Mone]

a vicodin induced daze! You should let Junkie tune your WHOLE car when hes like that. :)

[RTLarson]

pillz are good, i'll be by there in about an hour or so

Thanks!

[Junkie]

I'll be here,wife won't let me leave by myself anyway ;)

[cheappower82]

I've had similiar issues with two different alternators; at high rpm's (5K-plus), the charge light would come on and the headlights dim in and out vigorously. Never firured it out; still an issue.

My solution: race during daylight hours :eek4dance:

[Junkie]

Yep,charges at 14+ volts,battery with car not running at 13v.I'm guessing bad diode,shop hooked up charger/jumper backwards.

[RTLarson]

Thanks again buddy!

[Junkie]

No problem,come visit when I can move and my brain is reconected :D

[SupraWes]

I had that problem once it was a bad diode in the alternator.

[Donn29]

there is no single diode in an alt. there is 6. if the alt is putting out 14 plus, it should be fine. was the light on when you were checking voltage?

[Junkie]

there is no single diode in an alt. there is 6. if the alt is putting out 14 plus, it should be fine. was the light on when you were checking voltage?

Yes,light was on.Car runs fine.12+ volts with car off.Light was not on at start,at about 3k came on.Shut car off,pulled checked fuses,all well,start,no light,rev = light.Shut off,re-start,light is still on,reads 14+ volts.

[Donn29]

I'd swap it out, the light on the dash is usually connected to striaght to the VR. Meaning that the VR is basiclly turning on the "Check Alternator Light". I'd pull it and put it on an expensive tester. It could have excessive diode ripple or something else(meaing some of the diodes or the rectifier are not doing the AC to DC conversion properly). Basicly your getting some ac some dc voltage....

[Junkie]

LOL @ Check Alt. light --- exactly my thoughts when I seen it.We are taking it as .... Here is your warning,if I die on you,it's your fault.He won't have a chance to change it out until Mon.
I don't/didn't have a spare onsite,my parts stash is getting low,for common parts.

[RTLarson]

So last night my alt competly died on me, but i figured out why! Look
http://img410.imageshack.us/img410/5021/140360177029kp5.jpg
The post has been completly melted off!!

[Junkie]

I still have the loaner,if you haven't already taken care of it.Home all day ....again :(

[RTLarson]

Thanks, but i took care of it yesterday, it was under warranty. Good as new (again). Luckily jump-ing the car 3 times didn't kill the batt, cause i'm broke!