I've got an issue going on. It presents itself as a weak battery. Interior lights seem to be on OK, nice and bright. When I do anything to put a load on (turn on parking lights, put key in the ignition, or try to start it), it drops down. Lights go dim, and everything seems to act like a dead battery.

Tried charging the battery I had multiple times, same thing. Took it in (battery was at least 7 years old), they tested, said to replace. I replaced it. SAME THING is happening.

Where do I go from here? On a meter, I seem to read good voltage at the battery. Does this sound like it might be a bad ground? If so, where should I start looking?

Thanks!

https://www.fiero.nl/forum/Forum2/HTML/043240.html

quote Originally posted by phonedawgz: https://www.fiero.nl/forum/Forum2/HTML/043240.html

This is one of the best things anyone can do ton their car, Fiero or not...

Also; what is the alternator output under full load? Just in case you need a refresher, with the car running very carefully use a volt meter to check from negative battery terminal and other lead to the power out on the alternator with no power loads first revving to about 2k RPMs. Check numbers, should be around 14 volts. Throw on the AC/heater full blast, headlights, map lights and leave the door open for interior lights as well, check again, rev it up to about 2k RPMs. Voltage can could be a little bit lower than prior number , but still above mid 13 volts... Anything lower 13 volts usually means the alternator or wiring to the alternator is faulty. Don't use the gauge in the fiero to check voltage for this, its not super accurate and we want to know what the alternator itself is putting out.

[This message has been edited by Shho13 (edited 10-27-2014).]

Picked up a grounding strap... unfortunately it looks like the screw on my negative battery cable is a few threads short to let me install the cable. Wouldn't seem to screw on when I was holding it under the battery cable touching the battery. That said, i attached it to the intake as someone in that thread you guys referenced, and it seemed to do some good. I got good spark on the negative cable when trying to hook it up.

Eventually, I took it away and bolted the battery back on. Turned on the lights, started the car. ground strap was only connected at the intake, not to the battery. Shut it off, and went to try it later in the evening. Got the same battery drain as before.

This time I seemed to notice if I bumped the packs of wires that were near the battery (attached to the side wall, looks to be maybe the main run of wires) my trunk light would flicker. I wiggled those around a little, and the trunk light went off.

So I think my next step is to trace the small ground wire that's built into the battery cable that seems to run to that block.

trunk light staying on all the time?

quote Originally posted by pHoOl: This time I seemed to notice if I bumped the packs of wires that were near the battery (attached to the side wall, looks to be maybe the main run of wires) my trunk light would flicker. I wiggled those around a little, and the trunk light went off.

Big clue in that statement. The wires bundles (2 runs in 2 plugs) that are at the centre of the firewall (held in with one 8 mm screw) is a good place to look for your problem. Undo the screw, pull the 2 connectors out (one laps over the other) and inspect the spade connectors carefully. Especially the larger 14 to 12 gauge ones. Expect to see burned or green pins. Those spade connectors are way undersized for some of the loads put on them and most owners seem to add more load with newer toys.

This is not a Fiero issue, but a GM issue for cars that used the same size spade connectors for high load wiring. Take a look and write back with what you find.

Pete