ok, so heres how it went, The battery light came on and I figured the alternator was bad, so I stopped the car and let it idle while I disconnected the battery. The car kept running but the idle did change when I did this, it seemed to drop a little. ok so i figured there was nothing wrong with the alternator, however, I had the car out on the highway, and ran up to the suburbs from the city. 30 miles, and back another 30 miles plus a couple miles in between. finally, the car starts to stall, but it does not cut out, all the electric in the car goes out but the car keeps driving fine, next the car stahls to a complete idle and will not accelerate past 10 miles per hour. I drive her like this back to my pad and turn her off, now she won't re start. so i buy a new battery, to at least let me drive her to pepboys to get a new alternator. I put the battery in and she runs fine. Put the new alternator in and voila, nothing, the battery still drains and the car stahls when I disconnect the battery. thanks to anyone who can help me out here.

 

Probably a bad alternator new out of the box. Not as uncommon as you would think. Take it back and swap it for another unit.

On behalf of your car, please don't disconnect the battery with the engine running. The battery does more than just store energy, it also acts as an electrical "damper" in the charging system, protecting against voltage drops and spikes. Running without the battery is a good way to fry electronics in a hurry. It's faster and far easier to have the alternator bench tested at a parts storeor test it yourself with an ammeter/amp clamp and a voltmeter. Once you put the new alternator in, it's a great idea to service your battery cables and terminals to make sure the charging current can actually GET to the battery.

Only other thing I'd add is that on many cars, the alternator circuit is completed through thecharge bulb in the instrument panel. A bad connection in the harness/wiring between theinstrument cluster and the alternator can prevent the alternator fromcompleting the charging circuit,so that even with a properly working alternator, it does not charge the battery.

Regards - Adam

 

thank you so much man, I appreciate the help.

 

is battery lite on ??
does battery drain when car is parked or driven ??
you should have the charging system tested by a shop and ask them to do a electrical drain test ..

there is a write up about that in our DIY section

 

I know its 2011 and this is an old post, but did the problem get resolved? My 1991 Accord is doing exactly the same thing and its driving me crazy. Please reply as soon as possible.

 

The original poster is no longer registered, so I bet he won't be posting back.

So... troubleshooting this for yourself. What's the voltage at the battery posts when the car is running (engine idling)? How about idling with everything turned ON - lights, blower, defogger, stereo, everything?

Have you recently replaced your alternator like xbolloxx did?

 

I replaced the alternator 3 times and all the same problems so i dont think its the alternator. When they checked it at autozone the machine said diode and regulator was faulty and that was with all 3 alternators. When i was putting the alternator in (3rd one) i did notice that i could spin the alternator pulley with the belt on and the car wasnt even running. So i think my crank pulley is bad because the rubber piece spins without the pulley even moving. Have you ever heard of this before?

I did order a new OEM pulley on ebay and should get it either today or tomorrow. I will install it and see if it fixes the problem or do you think it could be something else besides belt slippage?

The most i have seen this alternator charge is at 13.5 volts running, but even that fluctuates a lot.

 

There is a slip ring (rubber) for the crank (on some generations). If the crank pulley is spinning when you turn the alt belt by hand.....yes, new pulley needed-rubber is gone....hope you have the tool or a really good impact....how long since the t-belt was replaced?

 

Thanks for the fast response. The timing belt was replaced about 2 months ago and the alternator and power-steering belts were replaced at the same time. I just got the new pulley today so i will put it on this afternoon and let you know how it goes.

 

You did confirm the "outer" part of the pulley is turning while the inner part is not...correct?