I was looking at my alt. gauges on my 97 Z28 on Sunday morning
it was at about 13.3 that's where it as read for about four years
with no problems. I noticed later on that day though it dropped down to right next to the red when I was idleing. The engine never failed though. When I got home I let it idle for 15 minutes with A-C on Max and bright lights, radio all accessories. The lights never flickered and the engine did not cut off.
Would someone please give me some suggestions.

Thanks

P.S. No problems on starting and the gauges look like it has always been a little off but has never went this close to red.
I just don't want to get stuck. I have replaced one or two batteries over the years but nothing out or the ordinary just regular wear and tear.
past

 

more than likely its your alternator. if it is charging, the metter should be at least at the 13.3 mark you said like it has been for four years. when the alternator is not charging the battery its like your running your car just on your battery thats why it is in the red probably close to or right at 12 volts beacuse the battery is 12 volts. running the radio ac max and bright lights on will just drain your battery. your battery wehn you got home was probably almost or close to being fully charged thats why it had enough juice to power all those accessories. another thing it might be is the voltage regulator in the alternator. that is supposed to control the voltage when the alternator is charging the battery, in other words not to overcharge not to undercharge the battery. that might be bad and send a signal to the voltmeter telling you its not charging. when you rev the motor up while idling does the voltmeter rise like its charging? when was the last time you replaced your alternator or repaired it? take your car to autozone, advance auto, napa, pep boys, your local auto parts store that has a battery/alternator tester and they can test both in the car with a load to see if one is failling. like i said more than likely its ur alternator sorry. also check your tension on the belt, the belt might be slipping too.

 

Thanks

 

Unless you do extended idling, you probably don't have too much to worry about. Check the system with a meter to be sure that the gauge is relatively accurate. The voltage output of the alternator seems to drop off significantly if the idle gets too low. Just a little more rpms and output can come up in a hurry. The older your battery is, the less reserve power it will have. It will be more susceptible to failure from lack of charge.

 

I don't do extended idling, you are right I was thinking the same thing. How do I check the system with a meter to be sure the gauge is accurate. I was thinking of stopping by O'Reilly and having them check it, the sales guy said he could check the voltage, before I buy a new alternator. The output does go up when the rpms go up.

thanks again