No Voltage from Alternator

WhatsUpDOHC

WhatsUpDOHC

MM.net Village Idiot
As you may have read in another post, The Marauder is down. It happened on Friday while driving home: lost all voltage and the car stalled. Installed a new alternator and new battery and still not getting any voltage from the alternator. Is there something that controls the output voltage from the alternator? We have measured it at the output lug with a meter and see no voltage.

Thanks!

Mark

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I've had 3 alternators in the car this weekend:

The first was the original- felt to be possibly going bad but test it out fine at my local Pep Boys (FLAPS).

Second is an alternator that I bought from Rodger Sims (MOTOWN) a couple of years ago - known to be used but still functioning.

The third is brand new purchased from Pep Boys.

The same symptom exists for all 3 - the battery is not getting charged my Scan Gauge showing ~11.3 volts.

Thanks!

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How old is your serpentine belt. No slipping? I'm just running through all possibilities.

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Any signs of corrosion in the relay box behind the battery?

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CBT said:
How old is your serpentine belt. No slipping? I'm just running through all possibilities.

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Click to expand...
~30K miles. Doesn't appear to be slipping.

Thanks!

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martyo said:
How proficient with tools and wiring are you?
Click to expand...
I made a crane out of an Erector Set once.

J/K

I'm no Edd China but I've been around the block. Also, my brother is a Navy trained electrician and he's coming over.

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WhatsUpDOHC said:
I made a crane out of an Erector Set once.

J/K

I'm no Edd China but I've been around the block. Also, my brother is a Navy trained electrician and he's coming over.

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Click to expand...

Take the PCM out of the equation.

The three pin connector on the alternator has a green wire with a red stripe. This wire needs to go to key on power. The other two are left alone.
 
martyo said:
Take the PCM out of the equation.

The three pin connector on the alternator has a green wire with a red stripe. This wire needs to go to key on power. The other two are left alone.
Click to expand...
Uncle. Taking it to the mechanic tomorrow.

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If you're seeing no voltage at the alternator that means the big charge wire is broken. When trilogy made those kits The positive wire was cut in half and extended at the passenger side valve cover. walk your little fingers from the alternator to the battery and make sure that big cable isn't cut in half.

Seen it twice
 
Turbov6Bryan said:
If you're seeing no voltage at the alternator that means the big charge wire is broken. When trilogy made those kits The positive wire was cut in half and extended at the passenger side valve cover. walk your little fingers from the alternator to the battery and make sure that big cable isn't cut in half.

Seen it twice
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This isn't on the Trilogy car, it's my daily driver. We're not seeing voltage from the alternator lug.

Thanks!

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martyo said:
Take the PCM out of the equation.



The three pin connector on the alternator has a green wire with a red stripe. This wire needs to go to key on power. The other two are left alone.
Click to expand...



THIS, if you get voltage, then look for the broken wire (most likely) or the bad pcm.


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Ol' SB has been in the shop for a week.

The mechanic hasn't been able to find the problem - All three alternators are fine.......

He thinks that it's the computer.

So, this weekend I may be reaching out to the marauder peeps for some help.

And maybe a computer for sale.

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If your mechanic is at all electrically-literate, give him this link. Scroll down about half-way and you'll see the discussion of how the PCM-controlled alternator works. There's a bit to wade through, but it's worth it.
 
Its real simple. One wire supplies battery power to the allternator. Another wire sends a signal to turn on. Its either 5V or 12, don't remember. The other wire is for the dash.

If it was me, I'd just borrow power from another source instead of replacing the computer.
Did he test the signal wire at the PCM yet?
 
Zack said:
Its real simple. One wire supplies battery power to the allternator. Another wire sends a signal to turn on. Its either 5V or 12, don't remember. The other wire is for the dash.

If it was me, I'd just borrow power from another source instead of replacing the computer.
Did he test the signal wire at the PCM yet?
Click to expand...

I offered that to him a week it so ago.

If he can’t do it he should show his mechanic.
 
Sorry for the lack of response. I really don't have the time to mess with the car during the week. I'll see what the weekend brings.

Also, I'm not a mechanic so I'm not familiar with some of the suggestions.

I appreciate all of the help!

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