Brand new battery - light still on.

[kingoftheroses]

I was having problems where I would be able to start my car only after playing with the positive terminal connection.

After some time of no problems, I'm driving home from the airport and the car starts bucking above 3000 RPM, the airbag light comes on, the battery light comes on, and finally, the car dies and holds up traffic in Miami for like an hour. It wouldn't even jump.

Ok so I start top and work my way down:

Replaced connectors on terminals - still nothing

Replaced the battery - car starts fine, then I let it idle with headlights and A/C on - it drains the new battery in like 10 minutes. Also, the battery light remained on even when the battery was installed.

So my question - is this an alternator issue? If so, is an alternator relacement something I can do on my own? If yes, are there directions online? Thanks.

97 Mitsu. GS

 

[mysticfire6602]

could be altenator, could also be anything electrical. replacing an alternator is fairly easy

 

[1Gtuner1G]

Definately your alternator. When you battery light comes on it almost always means your alternator is shot. Kind of a misleading light it should look like a friggin alternator

 

[tt281gt]

i too say its the alternator! turn on the car, unplug the negative side of the batt while on. if it turns off ur alternator is toast.

 

[91lizard]

i'm with these guys cept i thin the alternator is fine but a part in side it is bad you can have it fixed generally for like 35 bucks at an alternator rebuild shop...i think its the voltage regulator

 

[kingoftheroses]

OK --- I tried what you told me and pulled the negative off the battery and dead she went. So I put the car up on the ramps to try to pull the alternator and I had some issues:

1.) The bolts are seized but I'm going to try some penetrating oil

2.) How do I get the belt off? Because the belt is only attached to what looks like it could be the oil pump, there is no tensioner. How do I get the belt off???

This is the first time I'm doing this and I may sound dumb, but I'd like to do it myself for a feeling of satisfaction and to save some pennies. Thanks!!!

 

[oldman]

1. Soak it overnight with pb blaster and use a breaker bar if you need to.

2. Loosen the lock bolt near the alternator then loosen the adjustment bolt underneath it until the belt comes off. You really should invest in a service manaul, it will come in handy.

 

[ab0tj]

i too say its the alternator! turn on the car, unplug the negative side of the batt while on. if it turns off ur alternator is toast.

BAD idea on a car with a computer. This was fine back in the seventies when electronics were less sensitive, but not now. The battery acts as a filter since the alternator doesn't put out pure DC. If your alternator was good you could have toasted your ECU.

 

[tt281gt]

BAD idea on a car with a computer. This was fine back in the seventies when electronics were less sensitive, but not now. The battery acts as a filter since the alternator doesn't put out pure DC. If your alternator was good you could have toasted your ECU.

really? I do it all the time, not saying your wrong

 

[ab0tj]

really? I do it all the time, not saying your wrong

An alternator is a three-phase generator. This means it actually creates AC power, not DC. After three phase AC is rectified, it comes out pretty close to DC, but it still has spikes. The battery acts like a huge capacitor and filters the AC so that pure DC is available to the electronics. Ever hear the stereo in a car with a dying battery? The high pitched noise is alternator whine, which is occuring because the battery is not filtering very well anymore. It would be 10 times worse yet if that dying battery wasn't there. ECU's and other sensitive electronics can be damaged by the AC waves that cause alternator whine.

In short, yes, it might work, but then again you never know when your luck will run out.

-Alex-