Alternator Help!

**pRojekt02GT** · 10-27-2009, 12:40 AM

Got a bit of a problem..

I had summit UDP's on my car, with just a CAI..Battery meter kept dropping at night with the lites on, and when I'd hit the brakes it got even worse(abs light would pop on, lights really dim, radio shut off). It would only do that a little bit depending on how you were driving, as in how much you were on the brakes..or if you drove a long distance, and stopped and held the brakes in, it would not do it..

pretty sure I need to replace the alternator..

also took the alternator pulley from summit off and threw my stock one back on for a few weeks..didn't help..

what should I look for if I replace the alt, and it keeps doing this?

**How Much?** · 10-27-2009, 12:44 AM

If you replace the alt,,,,and it KEEPS doing it? Id say you have a short, or bare wire, or had a melt down, have you hooked up any crap that woulda caused this prob.. ?

**pRojekt02GT** · 10-27-2009, 12:49 AM

Originally Posted by How Much?

If you replace the alt,,,,and it KEEPS doing it? Id say you have a short, or bare wire, or had a melt down, have you hooked up any crap that woulda caused this prob.. ?

I have a two hundred watt amp and a ten inch sub..even with it totally disconnected and wires out it still does it..

**85stang** · 10-27-2009, 01:09 AM

hada problem, the lights would dim when i hit the brakes. was a short in the wiring.

**pRojekt02GT** · 10-27-2009, 01:20 AM

On your 01? Where was it located?

**juice_man_86** · 10-27-2009, 04:59 AM

the alternator pulley that comes with the underdrive kit actually speeds up the alternator a bit to compensate for the smaller crank pulley.

**pRojekt02GT** · 10-27-2009, 05:21 AM

Originally Posted by juice_man_86

the alternator pulley that comes with the underdrive kit actually speeds up the alternator a bit to compensate for the smaller crank pulley.

causing the alternator to work harder then if its smaller and spinning faster?

it seems the alternator is working too hard, or from everything i've done it is seeming to be my problem.

**daviac5000** · 10-27-2009, 10:41 AM

The (alternator) UDP is actually larger than stock and slows down the alternator. I threw on an overdrive pulley when I did my 3G upgrade. ASP makes one, but I also picked up one on Ebay recently. Have you checked/cleaned your grounds and other connections? If everything else looks good, have the alternator tested before you replace it.

Dave

**yellowstang03** · 10-27-2009, 11:32 AM

did you have a capacitor on your amp? if not and you used it alot it could have killed the altenator also. take it off and get them to check it and the battery i think they do it for free at advance.

**juice_man_86** · 10-27-2009, 01:59 PM

the pulley that came with my old kit was smaller

**pRojekt02GT** · 10-27-2009, 02:09 PM

Originally Posted by yellowstang03

did you have a capacitor on your amp? if not and you used it alot it could have killed the altenator also. take it off and get them to check it and the battery i think they do it for free at advance.

No, there was no capacitor on it..I had it disconnected for quite some time, but it kept doing it so I just reconnected it, and it never made a difference. (The system)

Originally Posted by juice_man_86

the pulley that came with my old kit was smaller

I hear that, but would that mean mean the alternator would work harder because its taking more revolutions to equal the equivalency of the stock pulley..correct? What kind of motor and car?

**Ares** · 10-27-2009, 06:10 PM

You want atleast a 2:1 ratio for altenator and crank pulleys. Think I have my car pullied to about 2.5:1 so it's making near peak output at idle and won't be over spun untill about 8000rpm so I have plenty of room.