1986 Fiero SE 2.8L V6 Notchback
As of about summertime I have been having this weird problem. Whenever The battery is anything but 100% charged up (as in if it sits for two weeks, untouched) I have this issue where the speakers have a pulsing thump to them when the key is in the 'run' position but the engine isn't running. When this situation is happening and I go to start the engine, the started is very slow and the voltage drops significantly and the engine barely gets going. However; if the car was just running (battery all charged up from alternator), none of these problems exists and it starts up just fine. I do not think this is the battery because I have swapped out the battery twice with brand new, charged up batteries since the problem has existed. This problem happens more frequently when it's cold outside. I have changed two of the fusible links in the back battery area with fuses of 30A each, but they have been in place and working before this problem was happening.
Here is a video of the situation. The Speakers thump like a heartbeat, but I can turn on the radio and sound comes out just fine, with the thumping in the background.Video for Electrical Problem
I need to get this problem resolved once and for all, because my dad and I changed the distributor O-Ring this weekend and I haven't been able to get the car to start, so fixing this issue must come before I start trying to diagnose that,