The other day out driving my 94 E150 4.9L, the voltmeter started bouncing rapidly up and down while driving along. Also the lights were flickering with it, so something was not right.

Lacking any better ideas, I pulled the battery cables off and thoroughly cleaned with with a post cleaner brush and the permatex brand battery cleaner and the purple spray on corrosion inhibitor.

It seems fine now, wiring to alternator seems good, no more flickering and no more bouncing votmeter needle.

Did I get lucky? They didn't seem all that dirty or loose, just a bit of grime on them and a little bit of white powdery buildup on the + post.

Or am I just waiting for the alternator to fail at some point?

Battery measures 13.3 volts right after shutdown - seems a bit high to me, but not terribly. Engine running, the electrical system is now delivering 14.6V - 14.4V at the battery terminals steady as a rock. Only time it deflects is kicking the heater on full blast and then only for split second until it is right back where it seems to stay.

A couple of weeks ago, I noticed the water level was a little low in the battery (an Interstate work-a-holic of unknown age). I added distilled water till it just barely touched the bottom of the filler tubes (they still vent as there's a slot down the side of the tube). Now I read that's actually a bit high according to interstate's web site. It should be 1/8 to 1/4 inch below.

Thoughts?

 

[updated:LAST EDITED ON 19-Dec-02 AT 11:51 PM (EST)]I had the same exact problem with my truck. My negative cable clamp was dirty and very loose. Cleanes them up and tightened em back up and the problem went away. Hmmm. And i thought is was my voltage regulator. Amazing what a can of coke, a wire brush, and adjustable wrench can fix.

 

I had that from a loose battery tray brace bouncing against the starter relay... Fortunately, when it welded thru the lower rivet, the brace just slid down BEHIND the smog pump pulley & rode a few miles making a slight grinding sound before I pulled it off the engine.

 

Cool, I feel a lot more betterer now.

:-X12

 

 

On my 87' 3/4 ton the volt gauge would go to about 15 volts and stay there moving back and forth just a little, and when it would move the battery light would come on but the light and gauge would stop once you turned on an electrical accesory. I had diagnosed it and found it was a bad voltage regulator. I replaced it with a new napa one (JUNK)
it lasted about 2 weeks then went back to the same thing. I bought a better parts master one and it has been working good since.

 

Mine is still hanging in there, solid as a rock. Must have been a dirty post.