Alternator Problems :( F**K

[7thgenvic]

Here is my problem,
I've replaced my alternator twice now thinking that the first was defective. All the wires and plugs were redone, as the old plug on the rear of the alternator was corroded.

After I charge the batter and the car works great, it somehow manages to loose power again. And while driving, it looses so much power that the cars electrical shuts down and will die completly.

Is this alternator problems, or is this something do do with the HID's i put in the car. Because of the day time running lights, i had to wire the lights into the high-beam inputs. Im thinking this might be a source of the problem.

Any advice would help.

[thinmyster]

Put a volt meter to your battery. the battery will put out 12V (not started). With the car started it should read 14V (If being charged properly) That will tell you if its being charged by the alternator. Dont know if that helps. it is 4am after all

[frozenrice]

Sounds like your battery is not holding it's charge anymore. It's a vicious cycle. If your alternator starts crapping out, it can ultimately wreck your battery if not dealt with in due time. If your battery is toast and you can end up overworking (burning out) your alternator. Best bet is to get your entire charging system checked.

[LilDrunkenSmurf]

I can't see it being HID's as they draw LESS power than normal bulbs (or should in theory).

I would get the battery checked out as well as the charging system. The voltmeter test works, but it doesn't tell if your battery is holding a charge, or how many amps the alternator is putting out.

[97'Scort]

Yeah, it's not your HIDs. Mine draw so much less power than my factory low beams that they set off my annoying little "Low Beam Failure" warning on my computer.

Make sure you're running an appropriate alternator for the car. I'm going to say you have a stock one, which is, let's say, 80A. Roughly 40% of that is required for normal car operation, or 32A. More is required under hard acceleration. If you have a stereo that constantly draws more than 40 amps, then you'll notice a decrease in performance.

Now, you won't be getting full power if you've put on an underdrive pulley to reduce drag. If you have, try putting the stock one back on. Also, make sure your belt is properly tensioned. It might be slipping, causing the alternator to stop spinning. Also check that it's not worn out while you're at it. Check the grounds and make sure they haven't wiggled loose or are attached to a rusted out spot.

[civicluva]

If its not the battery you probably have a short somewhere.

[7thgenvic]

thanks for the advice guys. I'm pretty sure that the problem might be a short. I have checked all the plugs all the grounds.
I still think it might be due to the fact of the alternator that the place has brought in. I'll go give it a couple more tries

the car is a lexus ls400. it shouldn't have a problem with the lights

[SR240SX]

So the car starts and runs right? but will die once you try to drive it?..to make sure its your alternator, start the car then un-plug your battery. If the car stays running your alternator should be good. Maybe bring it back and get it tested to make sure it is in good working order.

[7thgenvic]

So i just got the car back home. I boosted the car. and it started, I thought it may work after i took out all the headlight fuses, thinkig that was the area of shorting.

Got the car up my driveway and the car just started loosing power. I replaced the alternator and the battery last week. Im thinking the problem may be the cheap ass alternator they have given me twice..

[mrbojangles]

Hello, have you checked what the volts are at the battery with the car running and with it off as suggested?

That will tell you immediately about your charging system and you won't be second guessing the alternator.

[Supa Dexta]

You really have to check the output of the alt first with a volt meter, and see if you're getting ~14v when running... Theres been a lot of stories of junk alt's out of the box lately..

[7thgenvic]

So i think i figured out the problem.....there are at least 4 fuses that run from the battery terminal to the alternator. The fuse linkages are probably shot, hence the vehicle running directly off the battery. even when the alternator is trying to produce power. the power isn't getting through.....FUCk i hate lexus :)

[Darkane]

I was Gonna say Relay or fuses ;) Check the battery draw down on start up. You don't want it dropping to much or climbing slowly.