odd batery light

[Redfire6114]

Hey there new guy to the forums here. A little about me, Im from the Annapolis area MD, joined the marines right out of high school and work on the Marines light attack helos the Hueys and Cobras. I bought my cobra about 10 months ago from car max. anyway down to biz. In or out of gear when I reach about 3grand or higher the batt light comes on. when the rpms drop below 3g the light goes away. If I hold the rpms at about 2700 and hit the blinker or the horn or try to roll a window the light comes on. I took it to ford with the problem and they said it was that the alternator had low output. so i then took it out and ran to an advance auto and got it tested. they said it was fine, so i cleaned it up and put it back in and same problem. im thinking that advanced autos test was bs any opinions? thanks

 

[99riocobra]

honestly my guess would have been alternator. you could always buy one and replace it. if that doesn't fix it then switch it back and return it.

 

[01SN8K]

just to eliminate the battery i would load test it. if you have the time i would also get a buddy to help you out. run the car through various rpm's and see for yourself with a multimeter how much your car's charging system is putting out at different engine speeds.

 

[01cobravortech]

get that alternator replaced pronto! You don't want to risk having fuel starvation issues and then having your motor go boom!

 

[VincodeY]

+1

 

[racebronco2]

The diodes in the alternator are going out. If you don't have that many miles on it an auto electrical shop can replace them for you. They need to be soldered in place and the cost is about 60.00. In fact you could probably do it yourself or have one of your buddies do it.

Don't drive the car into boost, a friends car alternator had the same problem and he didn't notice it right away (open track during the day) and leaned out the engine. He had to replace the engine.

 

[Redfire6114]

Well ill try replaceing it tomorow and see how it goes, ill update with results, thanks for the help

 

[About2bite]

These alternators are notorious for not lasting, I definately would have changed it if i'd have gone through the trouble o pulling it out. Do you have a lower pulley on the car?

Josh

 

[Redfire6114]

no i dont

 

[Redfire6114]

Well since no one had the dam alternator i need i had to have someone order one, ill install it in a couple days

 

[About2bite]

You should talk to Steve @ Tousley if you have to order it:
http://www.svtperformance.com/forums/showthread.php?t=193978&highlight=steve+tousley

 

[Trick Pony]

So is there still no better aftermarket alternative for these alternators? I had to replace my stocker at 40k miles so I went with a lifetime warranty one from AutoZone knowing how they are notorious for not lasting. The replacement one only lasted 150 miles so I had to replace it all over again (was verified bad by AutoZone tester). Even though I don't have to pay any more for the part, I don't want to be left stranded or have to change this thing out all the time.

 

[Redfire6114]

put a new alt on it and the problem is gone for now, thx for the help