what would be the cause of the voltage to drop into the red zone sitting at a stop light. AC/heat off stereo on low (no subs) It felt like the car was going to die. I popped it into neutral reved it up to 2500 and the volt meter went back up to its normal 13ish volts.

Also on start up the volts take a LONG time to go upto 13ish volts unless I rev it up to 2000 in which it rises more quickly.

any ideas? because my parents solutions suck, and other than me thinking the alt is dying I have no evidance / way to support my side.

Bad Ground? Crud on the cables? Dead cell in the battery(what does the volt meter read BEFORE you turn the key to engage the starter)? And last, but not least, The Alternator!

it is the alt, that is what was happening before i installed my 140amp alt.

Yep, teltale signs your Alternator is failing. Those voltage drops are NOT good for your electronics [or so I have been informed about]. So, my suggestion is to replace it, plus it will eliminate the posibility of being stranded.


-justin

and it is killing your battery at the same time, you might want to replace that too, or you will be on a neverending cycle

very very low, maybe the top or just barely out of the red zone.

I am while running (normally) although at times it will just drop really hard. It is just really slow getting there and doesn't always stay up that high.


you're funny. I can't even get them to pay for new spark plugs!


Can an alt slowly fail or do they just fail straight out?[/quote]

[/quote]

no the alt can have a slow painfull death, the gauge should be about 9-10v with the key in the on position

With ours, it is usually slow and painful, but I have seen Alternators fail just out of the blue. Like my dad'* Suburban, he has a dual battery setup [running just under 2,000CCA total, and this is from the factory]. Because it is a diesel, you really don't need a whole lot of power to keep it running. Just enough to keep the computer on to fire the injectors. And just one day the lights started dimming and the Alternator just quit. Was this a freak incident? Possibly.

What has always happened on the Bonneville, is it would act up for a few weeks, then it would just flat out quit. One day, turn the key and the battery is either dead, or extremely low. This is one of the things that will leave you stranded.. my suggestion is to remove your'*, and put it back on. Carry the necessary tools to remove it, and carry a spare. I can remove mine is less than a minute, but since you have an SII, it will probably be more difficult.


-justin

i don't have money to get a spare.

I'm just going to let it ride, and if the car needs a ride because it failed I can shove it in their faces because they are too stupid to trust me.

Hey guys I have the same problem on my 92. But it only does it when the rear defroster is on. Added to the rear defroster is the heater, radio on low, lights and that is about it. It will drop down to about the mark between the red and 14 volts. A curiosity question. I have a 450 cranking amp battery on my car that was put on by the previous owners could there be a problem with the battery being too weak?