New battery and alternator - still not charging 91 rt-awd

456510456510 Band Wagon
in Electronics, Fueling & Air Conditioning
My battery light came on while driving home from work. The headlights were getting dim and the wipers slowed so I changed the alternator. The next day the battery went dead so I bought a new one and now that's going dead. The battery cables were green and dirty so I cleaned them up with sandpaper and all other wires seem to be ok. Anyone have a guess where i should look next? I'm working with limited tools and no voltage meter :disturbed:

I saw this on another civic forum but not too familiar with the wires he's talking about. "Well after long hours, changing the alternator again and a new battery, I finally figured it out!!!! The was a loose wire in the big wire harness that comes from where the ECU is. The wire was black and yellow"

Any help or suggestions would be greatly appreciated.

Steve

Comments

  • darktricksterdarktrickster Wagonist
    Check the big fuses in the underhood fuse box.
  • 456510456510 Band Wagon
    I took the alternator out and checked all the wires, while it was out I brought it back to Autozone to get it checked. It looks like the alternator was bad, a first for me but I've read enough to see it happens more times than it should.

    I took a peek at fuses just to see, thanks darktrickster. CURRENT PROJECT: 1988 rt4wd Civic Wagon - gotta love those rt4wds
  • 456510456510 Band Wagon
    After driving 40 or so miles the battery light started coming on. I was braking in a hard right turn when it first lit up. It comes on again when I brake and goes out when i slip it into neutral, when the battery light is on it goes on and off as I go from drive to neutral over and over again. No matter what i do I can't get the battery light up in neutral. Autozone said it was charging at idle so I guess I have a wire shorting out somewhere. Time to buy a meter and star poking around. I have a feeling this fix will be a pain in the ass.
  • darktricksterdarktrickster Wagonist
    pull the altenator belt and see if the light comes on in neutral, also try pulling a battery terminal off while the battery light is on (with the belt attached) and see if the car dies. Might just be the light is funky. Make sure the Two positive leads going into the underhood fusebox are both tight (both phillips head screws). If all that goes as it should, the meter might be the only option, take solace in the fact that there aren't that many wires directly connected to the altenator. :encouragement:
    Oh, and might want to make sure that your engine is properly grounded (the negative battery cable will route to the chassis under the battery tray then to the tranny somewhere).
  • 456510456510 Band Wagon
    I cleaned up all the grounds and checked the screws on the fusebox and that didn't help. The light hasn't been coming on as much and only once today while crossing some railroad tracks. I'm pretty sure there's a wire shorting out somewhere. Thanks again darktrickster.
  • darktricksterdarktrickster Wagonist
    you make sure the terminal on the top of the alternator was securely tightened? That could cause that kinda problem.
  • 456510456510 Band Wagon
    I checked the top of the alternator and I was able to nudge it a bit tighter. In my younger days I snapped a few bolts which caused all sorts of problems so I don't ape like I used to.
  • 456510456510 Band Wagon
    I think the I got another bad alternator from Autozone even though this was checked before I installed it. I never saw the battery light come on during test rides but while my wife was driving home from work the battery light comes on. It never comes on going to work (headlights on). The car died in the fast lane not long ago and she's really scared it's gonna happen again so she drives with radio, fan and lights off - this makes the battery light come on. So I drove it after work and sure enough with all accesories off the light comes on but as soon as I turn the heat or headlights on the light goes off, even stepping on the brakes turned the light off. I'm assuming the civic has a two level voltage regulator and it's not working on light loads but works fine on a heavier load. I googled this problem and I can't believe how many people struggle with this issue. I'm almost leaning towards going to a pick-n-pull instead of getting another piece of shit from Autozone.
  • darktricksterdarktrickster Wagonist
    Interesting, I've never heard of this. Good to know though. Thank you.
  • 2jzmiata2jzmiata Band Wagon
    I wonder if you have a broke wire that goes to the alternator to signal it to charge. Have you tried jumping the wires on the back of the alternator to try and force it to stay on for testing purposes? I know that sounds like a bad idea but it will help you determine if you have a bad wire or not and could possibly be something in the ECU acting strange. This picture of the charging circuit may help.117.jpg
  • Silvertoe88RTSilvertoe88RT Wagonist
    test your ELD...
  • monzstermonzster Band Wagon
    I have heard of this happening with aftermarket alternators on hondas. I would reccomend getting a denso alternator or taking your old one if it was a oe one and having it rebuilt at a shop.
  • 456510456510 Band Wagon
    I agree monzster, I've read about so, so many crap rebuilt alternators I think I'm not going to try my luck with a third cheap replacement from Autozone. My wife is still driving the car and the light doesn't come when there's high voltage use (headlights, fan and radio) but sure enough if you drive it long enough in a low voltage situation the alternator light comes on so I'm pretty sure the alternator has a faulty voltage regulator. I traded the oem as a core so I'm going to look and see if I can buy a denso somewhere in Portland. Thanks for the heads up!
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