[BlackTalon]

The alternator light in the Targa started flashing on while driving back and forth to Fredericksburg a few months back. I drove it once more after that (light flashed one again once or twice) and car was dead the next time I tried to start it, which was right before Christmas.

Tried recharging the battery and jumping it a few times in January, but nothing worked. Also noticed alternator belt was pretty loose.

Replaced the belt (new Continental) a few weekends ago, and noticed battery acid around base of battery. Fast-forward 3 weekends and $300 later, and battery got replaced with an Optima w/ adapter plate, and I added a few tools to the collection :XX After a jump start, the Optima sprang to life, and I let the car run for ~30 minutes, plus drove it around the neighborhood. Then I drove it to Dave Riley's last weekend to take care of brake work, oil change, etc. Started right up at my house, and again a few times at his garage. On the ride home though, the alternator light started flashing again.

I noticed the new belt seemed loose, so today I relocated the last 2 interior shims so the pulley is now tight to the alternator. Belt has less give, but still seems to deflect a bit. Had to jump start, as the ride back from Dave's seems to have drained the battery to just over 12 volts (I have a Sears battery charger with a 'test' mode). Took it out for a spin up and down 395, and the alternator light flashed on quite a bit. Seems to happen if engine is around 3,000 RPMs and the car hits a bump, or I accelerate sharply. Also came on when in a sweeper and hit a bump while revs were around 2k.

Both battery terminal connections and the nearby ground connection for the negative terminal seem tight. Alternator belt seems failry tight, although not as much as I would expect considering all the shims are outboard of the pulley. Alternator is a rebuilt Bosch unit, and was installed about 2-1/2 - 3 years ago. On the positive-side of the battery, there's an in-line fuse that was put in when the stereo system was installed a few years ago.

Any ideas/ suggestions of things I should check? I know that's an open-ended question with lots of potential for going off topic, but please hold off until after two or three serious replies

FWIW, I pretty much need to get this resolved Sunday if I'm going to make the DE weekend. I can't take any time off work next week except for Friday, and I'm supposed to be at the track that day. TIA,

[Vicegrip]

I would leave the belt tinkering aside and get my volt meter out. First find out what it is and is not doing as far as charging then look for reasons. Bad regulator or alt, loose wires on the alt, bad pins in a conector and the like. I would guess that the battery conections are good as you replaced it and this was happening with the old one. you can hook the meter up to the cigg lighter or other power point and drive the car around to watch the voltage and see what it does as you drive over bumps or past 3K or when the light comes onand goes off. This is just a starting point.

First hunch is the power output wire on the back of the alt is loose and fried but there are many things it could be.

forget guessing about what it might be and test the thing! I'll be out in the shop tonight if you want to limp it over.

[Trak Ratt]

Originally Posted by Kurt Mickelwait

First hunch is the power output wire on the back of the alt is loose and fried but there are many things it could be.

that's mine too (so is that one response or two cause I got to know about brake fluid )

[hoophead]

Check the brushes on the alternator. Unfortunately you'll need to take the whole thing out to check it. On my old '73, the rings (conductive areas around the shaft - maybe there's a better term?) on the alternator shaft had worn down to the point that the brushes were rubbing on the plastic separator between the rings, causing the brushes to not make contact for a significant part of the circumference, which seemed to be worse at particular RPMs.

I ended up shimming the brush holder out with a couple of small washers, which caused the brushes to be correctly centered on the rings and thus make full contact.

You've got a more modern car, so the regulator is probably built in to the alternator. I've never had a regulator die in the mode you are describing, but it's cheaper than an alternator and might be worth replacing just to see if it fixes it too. My experience with the bad regulators is either full dead or full overcharge.

[CrewChief]

Originally Posted by BlackTalon

The alternator light ... flashing on while driving back ... light flashed one again once or twice ... Tried recharging the battery and jumping it a few times ... but nothing worked ... noticed alternator belt was pretty loose ... Replaced the belt ... battery acid around base of battery ... battery replaced ... alternator light ... flashing ... drainged battery to just over 12 volts ... alternator light flashed quite a bit ... Seems to happen if engine is around 3,000 RPMs and the car hits a bump, or I accelerate sharply ... Also came on when ... hit a bump while revs were around 2k.

There's the essential information.

The new battery is dead because it wasn't getting charged. Just over 12 volts is around 50% dead or so. Could look it up; but you get the point.

The lose belt was a red herring.

Vibration causes the indicator light to 'flash'. Find the bad connection or wire.

[Lupin..the..3rd]

http://www.pelicanparts.com/techarti...eg_replace.htm

911 Alternator & Voltage Regulator
Removal/Replacement

[BlackTalon]

Thanks everyone. Hope to troubleshoot tonight.

[BlackTalon]

Thanks to Kurt, the charging problem has been identified and solved! The primary culprit was a bad connection where the main power wire connected up under the chassis. The wire was in place, but loose in the 'crimp', and was making intermittent contact. He also found a loose spark plug wire connection (wire was pulled out of crimp, but still in boot), which hopefully explains the hesistation in Turns 5 and 9 late last DE season. Got to see lots of diagnostic procedures, as well as watch the big-ass crimpers get put to work!

DR would be disappointed because no hammers were used. Maybe on the next project!

Also, while pulling out of the garage, the back-up lights were malfuctioning, Kurt fixed that as well.

As usual, Kurt saved the day and I'll make the DE weekend. And he kept me from wasting $ on a new alternator (which would have still not worked right), and saved my new $300 Optima battery! 8)

[Mike W]

Nice job. Glad (or Glade) you will be able to make the weekend. Kudos to Kurt once again!

And just to open the door so DR doesn't have to work too hard to get back at me.

http://www.autoblog.com/2007/02/23/m...this-saturday/

[Jazzbass]

And here I was going to suggest you just rewire the whole car. But I guess Kurt's method works, too.