Good morning forums,
Have a 1986 firebird base model, swapped with a chevy 350 with older heads, running V belts for power steering, alternator, and water pump. this is more of a general Chevy small block alternator issue. I just took apart all the accessories to hopefully swap to new ones, but that’ll have to wait as there are some things I can’t take off. So I put everything back together, and threw on a new V belt for the alternator. The belt is very tight, and the alternator is brand spanking new. Even got the new two pronged Plug thing that goes from the alternator back into the alternator on that little screw. The cable that goes from the alternator to the battery seems good too. then after adding coolant back and double checking all my bolts and hoses I fired her up, ran fine and seemed to charge the battery but not as it should. It stayed at 12 volts the entire time, which is what the battery should be when the car is sitting there off, when it’s running it should be at least like 13.6 volts. Revving the engine or setting a temporary high idle didn’t help, it just stayed at 12 volts. Really unsure what’s causing the new alternator to charge the battery but not charge it well enough. it’s a new alternator, new belt that’s tight, and the new
plug.

It ran for 10-15 minutes and the battery stayed at 12v, still had plenty of juice to fire up again after that because I forgot to move the car across the lot. Any alternating advice appreciated! Cheers.

 

Does the "Choke" light come on when you turn the key on but the engine isn't running?

 

unsure what the choke light is, but I believe I found the issue after driving it. The main power cable that goes from the battery underneath the engine to car was not secured, and was rubbing against the passenger header melting the cable. Would explain why it’s been getting worse as I drive it and also why it’s sort of okay at idle, because the cable isn’t touching the header. I will be having fun replacing a thick power cable this week. and I want to sell it because I am a ford guy

 

It's a warning light on the dash that says "Choke". The deal is, if the key is On but the alt isn't working, there's a light that used to say "Gen" or "Alt", or have a battery icon, or some such. The electric choke is wired such that it won't be fed power if the alt isn't working (such as if the key is On but the engine is not running), but rather, only when the alt is charging. Therefore if the alt is bad the choke will stay engaged. Da gummint decided that the choke condition, which impacts emissions HEAVILY, was more important to tell the driver, than warning that the alt isn't working. Kinda boneheaded if you ask me, butt w/e, it is what it is. Butt furthermore, if the light bulb burns out, the alt will never "know" that the key is even On in the first place, and it won't be told to start charging. So if the alt isn't charging, and also that light doesn't come on because it's burned out, it's possible that simply replacing the bulb, will fix the alt.

Yeah a melted batt cable touching bare metal somewhere will cause any number of things to go wrong. Hopefully that didn't damage the alt or something terrible like that.