vipernicus42

iTrader: (4)

Hey Guys,

So I've been having trouble with my alternator (see here) but I now know that the issue is not the alternator, nor its wiring. It's *somewhere else* in the electrical system. The question becomes what, and where.

I got the alternator re-rebuilt again and following the advice of the guy from the alternator shop I ran a brand new 14ga sense wire to its own fuse on my FC Fuse block, and a second charge wire (10ga) also to its own fuse on the FC Fuse block. I left the stock charge wire and dash wire in place.

I then put the battery on the trickle charger for a few days, had it load tested, and put it back in the car since the alternator rebuild guy said that having a completely dead battery can put enough strain on the alt to blow things.

With that setup the alternator should have had no issue sensing the battery voltage or getting enough current through the charge wires.

I started the car and let it idle for a few minutes. Multimetre showed 14v across the battery terminals with the car on and idling, 12.5ish with it turned off. Perfect.

I took the car for a short drive and I got about 2km before I realized that my console was shining with the brightness of a thousand suns and I could smell something funny.

I pulled over, and put my multimeter across the battery terminals to see what was up. At idle I had 19 volts. I shut the car off right away. I could hear a slight hissing from the overcharged battery as some of the electrolyte had evaporated and was trying to escape. With the car off my battery now showed almost 14v on its own!


So something is blowing the voltage regulator in my alternators. It's not a bad sense wire, it's not an inadequately large charge wire. It's something somewhere else.


The question now is how do I go about tracking this down without blowing the alt two or three more times. I managed to drive the car home on just the battery (with the alt completely disconnected, sitting in the hatch). So I know I can start and move the car on battery power alone for troubleshooting at least.

And of course I now need to replace some parts that have gotten blown in the process:

- Gauge cluster (only speedo works, all other gauges forked)
- Fuel pump relay (was replaced by a piece of wire for the time being)
- Signal light relay (signals blink at mach speed on the console, but don't light up outside)

And I'm sure I'll be finding more as I chase these electrical gremlins for the next year or so!


Any suggestions on how to figure out what's blowing my alts? It's starting to get cold here so I've got a month before my car has to go into storage. With daytime temperatures hovering around 10C it's quickly going to become unpleasant to work on the car, so stripping the entire wiring harness wire by wire is not the ideal solution but I'll do it if I have to.

Jon

Kentetsu

Jon, I had a similar situation a while back. I was blowing headlight bulbs out because the alternator would suddenly start trying to charge at 18+ volts. This turned out to be caused by a loose connection of the positive cable at the starter, which was causing erratic readings from the sense wire. When the bad connection would fail, the sensor wire would suddenly report to the alternator that the battery was dead and needed lots of juice. Then blam go the headlights.

Probably not your issue though, since I'm sure your connections were the first thing you checked. Good luck!



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vipernicus42

iTrader: (4)

Hmm.... Well I checked it once, but it's worth a second check. At this point I'll try/check pretty much anything.

Jon

gsl-se addict

iTrader: (3)

Also check grounds. You need a good ground between the alt and engine. If you have the alt or WP powdercoated or painted, you will probably need to scrape some off to get ground. Also the connection from the battery (-) to engine could cause this. Check battery terminals and clean as needed. Check battery (+) to the FC fuebox and the connections for the fuse box to the alt.

It is as Ken says. If the connection to the sense wire or to the ground is broken/poor, the alt will kick it into high gear and start putting out its maximum output. This causes the high voltage, which in turn, starts blowing things out.

Man_in_black49464

iTrader: (1)

A sudden alternator spike is typically caused by a bad diode in the alternator itself.
When the diode actually "Fails" to fail properly the signal can get diverted in random order, this can create a spike depending on which diode it is will depend on the size of the spike some can fail like this with you never knowing.

The semi failure of a diode is caused by the "silicone grains" when they mold the silicone they cannot line up each molecule basing to be linear so there are impurities they shift and half instead of totally fail so there is a "Proverbial arch" in the system once this happens It will never follow the same grain but there are millions of these grains in a single diode.

I would replace the alternator, it will save you some trouble.

If you don't have the cash flow for that then just sit and run a electrically charged magnet over the alternator casing every 300 or so miles or 30 hours of use.

So in other words replace the unit for hassle free use