StrangeCharging issue
 

I have a 98 1500 with a 4.3. The truck charges fine while idling but but while driving especially under acceleration the gauge drops to Bat voltage. It doesn't happen all the time and it doesn't matter if it is light or hard acceleration. It is very intermittent but happens enough to be a concern. I replaced the alternator thinking it could be something with the internal regulator and it made no difference I just replaced the belt tensioner which was weaker than the new one but still having the problem. The Bat. light also flashes when the gauge drops. If I take my foot off the gas and shift to neutral it goes back up.
Any ideas? The battery hasn't died but I am afraid to go to far from home now. It acts the same no matter how many things I turn on. The truck is a W/T with no power accessarys.

Re: StrangeCharging issue
 

check your grounds and the power feed wire from the alt to the battery. also check the fuseable link could be bad. hope this helps. had a similar problem on my 97 it was a bad tensioner causing a squealing and voltage drop in my case. changed the belt too it was glazed from the bad tensioner.

Re: StrangeCharging issue
 

I went under to change the oil this evening and started looking around and the ground strap from the back of the head to the frame just fell apart when I touched it. I then went up top and pulled on the other woven strap from the firewall to the frame and that to came apart. Just made the part store before closing and replaced both grounds will road test in the AM. I couldn't get a socket to the ground behind the head due to trans dipstick tube in the way so just ran the ground to the oil dipstick bolt. Tooth washers and all hardware cleaned up.

Re: StrangeCharging issue
 

New ground straps didn't fix it. I will try a jumper wire next from Bat. to Alt to bypass fusable link. It charges fine at idle even with all lights and accessories on yet cuts out intermittently while driving mostly under exceleration.