Weird charging system issue

[97xlt4.0]

Hey guys,

I already posted in the New Member forum...and now I need a bit of help.

A couple of weeks ago, while driving in a rainstorm, I noticed my Ex did some funny things.....mainly the battery gauge. Noticed while driving in stop/go traffic that when the engine rpm was close to idle and I was not moving, that the gauge started going down, but then went right back to normal as soon as the engine speed picked back up....but using any accessory(power windows, etc.) made the gauge drop noticeably as well....

My Ex is a 97 XLT, 4.0 SOHC, auto, and roughly 171k miles. Within the past week or so, I've done a complete oil change on it, put a new air filter in, and just today I changed out the neg. battery terminal for a new one(old one was rusted!!)


I've only noticed it behaving funny when I'm driving during a rainstorm, or otherwise when the vehicle gets wet.....

Has anybody had a similar issue??

Thanks!

-Mike

 

[BrooklynBay]

Check the voltage of the charging system while it's running, then with the lights, A/C, and the defroster on. Compare the voltage readings.

 

[97xlt4.0]

Thanks, I will do that tomorrow! I'm kind of eying the battery as suspect, regardless....from what the prev. owner told me, its at least 8-10 years old, which im thinking is on the long end of things, even for an Optima!! lol.

 

[BrooklynBay]

Check the battery terminals for rust, and corrosion.

 

[97xlt4.0]

Replaced the neg. one today for exactly that....it was rusted. Ran into a snag with the positive one, though....at least on my Ex, the pos. cable has NO slack at all, to cut the bad terminal off and put a new one on.

I've noticed on top of the battery that it is noticeable where water puddles up on top of it, or at least it looks like it has been....

 

[BrooklynBay]

You replaced the terminal or the whole wire? You might be better off replacing the entire wire if the wire is in bad condition or if it's not long enough to attach a new terminal.

 

[97xlt4.0]

Oops, i guess i didnt explain that very well!!

On the neg. one, there was enough slack that i replaced the terminal. On the pos. one, I haven't done anything with it yet, once I discovered there's not enough extra cable....the terminal for it does not look as bad as the other one was, but I am going to pull and clean it tomorrow just to be safe.

 

[BrooklynBay]

It's a good idea to use an antioxidant coating on the terminals to prevent any future corrosion from accumulating.

 

[Ford_Racing_Guy]

i've either used battery terminal spray, or simply coating the terminal with white lithium grease.

I had a similar problem with my 92 awhile back, turned out to be a cracked cable end and allowed it to loosen up on the terminal.

 

[97xlt4.0]

Haven't had a chance to work on the Ex today, but did come across a 'splice kit' at Carquest, that came with everything to splice in a new piece of battery cable. Thinking of getting one and doing it this next weekend.

Also.......does anybody have a pic of your battery hold-down? Mine doesn't seem to have much holding it in place....

 

[Dilbert5]

I recomend replacing the cable, getting a good splice is hard, and could end up causing more problems. They do have universal cables at a very reasonable price. Just make sure that you route the cable so that it does not rub on anything.

For 97, the battery hold down was a wedge shaped piece with one bolt down the center. It bolts to the bottom of the battery tray, on one side. As long as you have the correct size battery, it does a good job of holding the battery in place.

 

[97xlt4.0]

Well, while I was out looking earlier under the hood, I saw the battery hold down thing.....the Optima that I have is definitely NOT the stock size....LOL.

As far as replacing the cable.....I don't have a garage or anything, as I live in an apartment. Is replacing it something that could be done in a parking lot, say in a day??

 

[BrooklynBay]

It shouldn't take that long to replace a cable.

 

[97xlt4.0]

sweet, i know what im doing next weekend.....or at some point!

 

[Ford_Racing_Guy]

if you do the splice you can get crimpable connectors that have a slit in it to lay in solder.

if you do it right a splice will be fine, just make sure you put a good piece of shrink tube over the splice.

 

[my98nnj]

Don't over look the obvious, if you're having the issue only when it rains check the drive belt. If it's old it might be slipping when it's very wet outside. Also make sure your tensioner is in good working order. There are scribe marks on it to indicate when the belt has streatched to much. If your outside the marks, replace the belt.

 

[97xlt4.0]

Hmmmm.....the belt is brand new(well, a week old now!), I will take a closer look at the tensioner this weekend and see what I can see.