Fortunately I have a two year warranty on the alternator.

My battery is fine, it is 1 month old, and still my alternator is now dead.

Anytime I'm driving my car and I look at the voltage gauge, it reads around 16 volts so I don't know if it's cooking itself or what.

What could be the problem?

Thanks,
Rob

 

16 sounds a little high for the voltage. do you have anything extra installed to make the alt. work harder (full field)? been a while since i had a "stock" thirdgen, but i think my iroc stayed between 9 and 14.

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ICON Motorsports
1st & 3rd

[This message has been edited by ede (edited December 10, 2000).]

 

forgot to add this, a lot of rebuilt parts are of questionable quality. if you've been buying parts from one of the big discount stores that may be the problem. i've had 3 straters on my daughters car since summer.

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ICON Motorsports
1st & 3rd

 

Nope, I don't have any extra stereo equipment or anything like that.

Its funny, last time I went into the auto parts store (it is not WalMart, they only sell car parts) I told the guy this was the THIRD time and he is like "Well, that shouldnt be. Gee Gosh, well I GUESS I will let you trade this in." Yeah how about I go get my baseball bat out of my car, I knock you out, and I go grab myself a lifetime supply of alternators from under the counter there buddy? Grrr.

 

Rob, I'd take a peek at your grounds and also at the wire from the alt. to the batt.

 

Rob,

I'll second Ed's conclusion. 16V sounds a little high. That is controlled by load, alternator output capacity, and the voltage regulator.

Obviously your load isn't excessive for the capacity of the alternator, or the voltage would be lower (E/R=I).

Since the voltage regualtor is an integral part of the alternator, the voltage output is a function of the setpoint of the regulator and any resistances from connections to the alternator, excitation (stator) wiring, and battery connections.

Verify that the voltmeter is correct with a second hand held DMM. If it is correct, the auto parts store may have a batch of rebuilds with questionalble regulators. Ask them to bench test the next replacement with a nominal load and actually measure the output voltage before you accept the replacement. Maybe they'll see what you mean.

Operating at higher voltage can have some advantages (I used to tweak the adjsutable regulators up to about 15VDC), but can also boil the battery dry in short order. This isn't only hard on the battery, but the sulfuric acid can't be good for the battery tray, inner fender, hood, etc.

Alternator RPM, load, and connections are somewhat irrelevant in this case, since you are apparently over generating. You must have a good ground at the alternator, of course, but most other connections being poor would tend to lower, not raise, the output voltage.

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Later,
Vader
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"No matter how hard you try you can't stop us now"
Adobe Acrobat Reader 4.0

[This message has been edited by Vader (edited December 10, 2000).]

 

Vader and Ede, thanks for the advice. I figured it was more complicated than just having a working battery.

Actually, the single wire that bolts onto the alternator (not the plug) is being held on by a nut I found in my basement, since the pole type is a bit different on the replacement they gave me. So maybe my improvisation caused some kind of weak link.

I'll check out those things you recommended when I get home later today.

Thanks,
Rob

 

You didn't mention what brand alternator you had, but in my experiences, there are only a few brands of starters and alternators that don't completely suck. I would NEVER buy one from Parts America or a similar outlet. PA is now selling some Delco stuff, and Delco is about all I trust with alternators and starters. Macgyver worked at Parts America and took some pictures of a brand new 'rebuilt' alternator. It was horrible. I've rebuilt a couple alternators, but both times I used diode packs that my father already had. I don't know what sort or rebuild kits are available, but if there are Delco kits I would probably trust them. The rebuild itself is basically a piece of cake.

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The IROC Homepage
<A HREF="http://www.rit.edu/~jli4307/camaro" TARGET=_blank>
View the restoration of an 85 IROC</A>
"I didn't know a bored out Ford could go so slow" -Shenandoah

 

You may want to check the voltage on the sensing terminal of the alternator. This is in the plug. I can't remember which one right off, but if nobody else knows it off hand, I can look it up at work tomorrow.

If that voltage is lower than the actual battery voltage, the alternator could be charging more than it's supposed to, because it thinks the voltage is low!

Nominal voltage is 13.5-15.0 volts. 16 is definately WAY to high!

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Working on:
'84 Z28 LG4 305
Added dual elec fans.
145 MPH IROC Speedo
Building 430 HP 350
using primarily GMPP parts.
Block is in shop!

Awaiting results from all 8 ASE tests.

Starting to look like the Kicker poster child!

 

Hey Vader, did you ever see the movie "Repo Man"? That's what my dash lights reminded me of in my 69 the last time my alternator was overcharging due to a bad voltage regulator. Had to drive with sunglasses on at night! Lol. Btw, if you hear hissing from under the hood, and your battery looks like it needs to visit Jenny Craig, better shut the hood and leave it alone until it discharges a little!



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89RS w/350 TPI; 69RS/SS w/450 HP 350/Muncie 4-Speed "Too weird to live, too rare to die."