Battery not charging code

[Chris]

Hi guys, its been a while - I've been busy and the car's been running great

On the way home from work today, I made a few stops with no problem. Leaving my last stop, I got the BATTERY VOLTAGE HIGH followed by BATTERY NO CHARGE. Codes were P016 (voltage out of range), P110 (generator L-terminal circuit problem) and IO42 (battery voltage too high).

I shut off the car and restarted. Before starting, voltage at 12V. After starting, voltage rose in increments of 0.2V every couple seconds until hitting ~16V when those messages showed up.

Since I had notived corrosion around the battery terminals, I cleaned them off with a wire brush. Started car again and it idled for a few minutes no problem. Started driving and got BATTERY NO CHARGE again. Stopped for a red light and the error messages went away. This happend (normal voltage at idle, NO CHARGE at speed) a few times until I got home.

At home, I cleaned more of the buildup off the positive terminal and started up again. Same problem as at the grocery store - voltage immediately began to rise.

This is different symtoms than 4 years ago when I replaced my alternator - at that time, the lights all flickered and the voltage was unstable (not excessively high).

The battery must be really old (it came with the car 5 years ago and looked just as old then) but it cranks ok so I don't think it is the problem. I also dont think corrosion on battery terminals can be problem for the same reason. Does this sound reasonable?

Is there anything to check besides the alternator/voltage regulator (it would pain me to replace that sucker again!)

Thanks a lot guys!

-Chris

[Ranger]

Have the battery tested. If it checks out OK, then it's likely the alternator. Did you replace the alternator with an A/C Delco or aftermarket?

[MAC]

According to the '94 factory Service Manual, if you get the I041 or I042 code you should make sure the battery is properly grounded. I suggest cleaning the ground connection and making sure it's nice and tight. Just follow the negative battery cable to where it's grounded; if I remember correctly, to a front support beam near the radiator and close to the battery. This may not solve the problem since there are other possible causes for these codes but it's certainly worth the effort to find out.

[Chris]

Thanks for the replies, Ranger & MAC!

I went out and checked the ground from the battery and the ground contacts seem good.

Figured I would drive it up the block to the mechanic for a load test but battery is completely dead.

Now I'm really thinking the battery was just on its last legs, but it seems strange to me that it started fine yesterday (didnt have problems until engine revved up a little). Doesn't the starter draw more power than the coil packs at mid-high RPMs?

The other thing i was wondering is could there be something else shorting... something that would run on stand-by (ie that would run overnight) and while engine running but that was shut off when starting (ie radio, blower fan etc)....?

Ranger - I'm not actually sure about the brand, I suspect it is aftermarket. It was one of the first things to go when I got the car (and before I found this board).