I've seen a couple threads claiming to have solved their idle situations when they replaced their batteries, so I became hopeful. I have been chasing down an idle situation for the past year or so, and I've done almost everything (all regular maintanence items performed...). Ocassionally, my engine speed will fall below the idle when clutching and coming to a stop, but at other times, it will do this the whole ride. I can't put my finger on a cause.
So anyways, I thought it might be something electrical because the day of my tint, after I parked my car back at school, and was making sure the windows were up, so I pulled the window switches up and the lights went REALLY dim, dimmer than I've ever seen them. So, I did it again, only for a split second, and the same thing happened. So to really test it, I pulled up, but didn't let go, and my lights and everything went really dim, as before, but then my car shut off it was draining so much.
I went on google, and found a site describing a few ways to test the charging system. http://www.econofix.com/battery.html
Walked out with a multimeter, tested the battery without the car on: 12.6 Volts.
Put my lights on without the car started: they seemed pretty bright.
Kept the lights on, tried to start the car, and the lights dimmed/shut off while cranking.
Tested the voltage at the battery when the car was running: 14.34-14.37 Volts.
Felt the terminals to check if one or both were getting hot: both were cold still.
The voltages when my car was and was not running seem to show my battery/charging system is fine, however the lights went dim while cranking, plus my other symptoms outlined above, seem to show my battery or something isn't right.
What does this all mean?? Sorry this seems like such a noob question, but I need some advice on what my data is telling me.
Thanks.

 

Oh, and no extended cranks. However after the car has been running for a while, and sits for a little bit while still hot, my car will crank longer and will not start "strongly". The start will feel hesitated and won't shoot up to 1500 rpms and then back down, itstead, it stumbles lower, and finally shoots up, and then settles back down. It's kind of hard to explain.

 

If your battery is more than 3yrs old, it wouldn't hurt to replace it (even as a regular maintenance item).

 

Well, is my alternator at least ok? I don't mind spending the money on a battery, but the alternator would annoy me if I had to replace.

 

The fact that your electrical system is failing under load suggests that your alternator is not working properly also. You could just go to an Autozone or the like and have the charging system tested. If the problem is as severe as you describe, it should be fairly straightforward for them to identify the root cause of the problem.

 

That's not exactly what I was hoping to hear, but thanks for the reply.

 

Ive got a similar situation on mine, turning on the heat, rolling 1 or more windows all dims my headlights, even with the car running. Battery is ~2 years old, terminals look like crap, would getting new terminals help the situation? Also i heard about cleaning the grounds, which grounds would be ideal, given there are tons all over the car.

 

the battery may be getting weak. the headlights should dim when you crank the engine but not shut off. a good, fully charged battery will drop to 10 volts, maybe 9.5 when cranking the engine (headlights off). if you are still curious, disable the ignition so it won't start and crank the engine and measure the voltage.

if you have a bad battery, it could go down to 8 volts and the car would probably start but you would hear that it wasn't cranking full speed. a good alternator (which it sounds like you have) will re-charge the battery for the voltage tests that you did.

 

Oh you guys are just getting my hopes up now...haha. I'm going to Advance Auto tomorrow to get it checked out, so we'll have an answer. Thanks for the help!

 

just how old is the battery anyway? i would be absolutely amazed if you still had the original battery. the battery advertisements make it sound like they will last, forever but i would like to get 5 years out of one.

stay away from excide batteries. i can't get 2 years out of those pieces of garbage.

 

If you do decide to replace your battery.

1. Optima
2. Interstate
3. Sears Diehard Gold
4. EverStart

 

Damn, there was a thread that had a Wal-mart battery that Joosdawg was raving about, I believe it was the EverStart. He worked in the factory or something like that, and the battery he was referring to cost $58. I'm going to have to find that thread. Man, in the last week or two, I've spent too much money on my car, I really hope it isn't an alternator.

 

Everstart MAXX 1N. $58.84 installed at any wal-mart tire and lube express.

 

When you turn on your lights with engine running what does the volts read? How fast does it drain engine off lights on?