HELP! 86'Firebird 2.8 won't charge more than 12V

(Gil) wrote in message om>...
> (Bigjfig) wrote in message >...
> > >Subject: HELP! 86'Firebird 2.8 won't charge more than 12V
> > >From: (Gil)
> > >Date: 5/3/2004 12:42 AM Eastern Daylight Time
> > >Message-id: >
> > >
> > >My Son swaped a bone yard 85 camaro 2.8v6 into an 86 Firebird.
> > >Runs great for about 10 20 miniutes, untill volts drop down, down down
> > >till she runs out of battery!
> > >New Battery- New Alt (bench tested at 15V twice)
> > >Voltmeter on dash says it starts up at 12V.
> > >Battery checks the same 12V
> > >Big terminal on Alt check same 12V
> > >
> > >All three points check the same readings, even as the volts start
> > >droping down to about 7-8 volts. As it goes down you have about
> > >2minites to compair & check points till she's dead.
> > >
> > >Charge Batt & away we go again for another 10-20 minites
> > >
> > >Checked & cleaned as many ground wires were accessable. Big one on
> > >front of engine - back one by firewall - one big gouping connected to
> > >the back of the head we could not really get at, but we just put them
> > >on when installing the engine.
> > >
> > >Checked terminals at starter R & S + big positive cable.
> > >
> > >Got us stumped why the voltage reg wont kick in when on the vehicle.
> > >On the bench - no problem!
> > >
> > >Where to look now?
> > >
> > >Thanks in advance!
> > >Gil
> > >
> >
> > If you check your output with a digital meter, what do you get? Your alternator
> > may very well be wasted even though it was "bench tested".
> >
> >
> > Joe--ASE Certified Parts Specialist & 10th Ann.Club Tech Director
> > '80 Carousel Red Turbo T/A, 26k orig.
> > '79 "Y89" 400/4 speed 10th Ann. T/A, 57k orig
> > '84 Olds 88 Royale Bgm 2 dr, 307 "Rocket" (lol), 141k and still going....
> > '80 T/A project car...
>
> My anologe vom is fairly close +-.25V by eye reading.
> The alt output at big red terminl reads exaclty the same as the the dash
>
> Gil

I'm a Ford man, so this GM stuff has got me stumped.
I'd really like to get this thing on the road & not take it to a shop
so I can pay them to guess like me.
Any other idea's on what to try next?
Please e-mail me also, Its hard to check all the groups.
Thanks

Gil

I hate stuff like this because its all really a guess unless you have the
right trouble shooting manuals from the factory.
Here are a few things off the top of my head....
First off, although it sounds weird it could be possible for an alt to check
out fine on the bench but when it actually is in the car it wont charge. Who
bench checked it and how did they do the bench check? Did they open it up
and check everything inside with an ohm meter?
I don't know which cars had this problem (I cant remember but I think it was
a GM) but here it is anyway. As far as i can remember certain GM engines had
a bad or insufficient ground going from the alternator itself to the engine.
Even though the alt is mounted to a metal bracket that is mounted to the
engine it still couldnt get a good enough ground and the alt wouldnt charge.
It seems impossible but i've seen it happen. More than likely this isn't
your problem but at least its something to think about. You could always run
a wire from the alt mounting bolt to a really clean engine ground to see if
it helps.
These cars do have internal regulators right?

Mike
MuscularMustangs.com
http://www.muscularmustangs.com
"Gil" > wrote in message
m...
> (Gil) wrote in message
om>...
> > (Bigjfig) wrote in message
>...
> > > >Subject: HELP! 86'Firebird 2.8 won't charge more than 12V
> > > >From: (Gil)
> > > >Date: 5/3/2004 12:42 AM Eastern Daylight Time
> > > >Message-id: >
> > > >
> > > >My Son swaped a bone yard 85 camaro 2.8v6 into an 86 Firebird.
> > > >Runs great for about 10 20 miniutes, untill volts drop down, down
down
> > > >till she runs out of battery!
> > > >New Battery- New Alt (bench tested at 15V twice)
> > > >Voltmeter on dash says it starts up at 12V.
> > > >Battery checks the same 12V
> > > >Big terminal on Alt check same 12V
> > > >
> > > >All three points check the same readings, even as the volts start
> > > >droping down to about 7-8 volts. As it goes down you have about
> > > >2minites to compair & check points till she's dead.
> > > >
> > > >Charge Batt & away we go again for another 10-20 minites
> > > >
> > > >Checked & cleaned as many ground wires were accessable. Big one on
> > > >front of engine - back one by firewall - one big gouping connected to
> > > >the back of the head we could not really get at, but we just put them
> > > >on when installing the engine.
> > > >
> > > >Checked terminals at starter R & S + big positive cable.
> > > >
> > > >Got us stumped why the voltage reg wont kick in when on the vehicle.
> > > >On the bench - no problem!
> > > >
> > > >Where to look now?
> > > >
> > > >Thanks in advance!
> > > >Gil
> > > >
> > >
> > > If you check your output with a digital meter, what do you get? Your
alternator
> > > may very well be wasted even though it was "bench tested".
> > >
> > >
> > > Joe--ASE Certified Parts Specialist & 10th Ann.Club Tech Director
> > > '80 Carousel Red Turbo T/A, 26k orig.
> > > '79 "Y89" 400/4 speed 10th Ann. T/A, 57k orig
> > > '84 Olds 88 Royale Bgm 2 dr, 307 "Rocket" (lol), 141k and still
going....
> > > '80 T/A project car...
> >
> > My anologe vom is fairly close +-.25V by eye reading.
> > The alt output at big red terminl reads exaclty the same as the the dash
> >
> > Gil
>
> I'm a Ford man, so this GM stuff has got me stumped.
> I'd really like to get this thing on the road & not take it to a shop
> so I can pay them to guess like me.
> Any other idea's on what to try next?
> Please e-mail me also, Its hard to check all the groups.
> Thanks
>
> Gil

The plug that plugs into the alternator:

One terminal is for the light/gauge, and one terminal excites the field.
When the battery is fully charged, turn on the key with the white plug
removed from the alternator to see if you are receiving current to the
terminals on the white plug.

When it was bench tested, they put twelve volts to the field terminal in the
alternator. If you aren't receiving voltage to the white plug when you turn
on the key, the field isn't getting the current to cause the magnetism,
hence. No charge.

First look at the fuses, possibly there will be a charge, alt, batt, gauge
fuse. it might be as simple as that. If not, you're in for some diagnostics.

I think the web site is www.aldata.com and for like $25.00 you'll have
access to every piece of diagnostic, and maintenance data for your car.
Better than having a bunch of shop manuals, and what they don't have. Call
the 800 number and they'll get it for you.

Refinish King


"Gil" > wrote in message
m...
> (Gil) wrote in message
om>...
> > (Bigjfig) wrote in message
>...
> > > >Subject: HELP! 86'Firebird 2.8 won't charge more than 12V
> > > >From: (Gil)
> > > >Date: 5/3/2004 12:42 AM Eastern Daylight Time
> > > >Message-id: >
> > > >
> > > >My Son swaped a bone yard 85 camaro 2.8v6 into an 86 Firebird.
> > > >Runs great for about 10 20 miniutes, untill volts drop down, down
down
> > > >till she runs out of battery!
> > > >New Battery- New Alt (bench tested at 15V twice)
> > > >Voltmeter on dash says it starts up at 12V.
> > > >Battery checks the same 12V
> > > >Big terminal on Alt check same 12V
> > > >
> > > >All three points check the same readings, even as the volts start
> > > >droping down to about 7-8 volts. As it goes down you have about
> > > >2minites to compair & check points till she's dead.
> > > >
> > > >Charge Batt & away we go again for another 10-20 minites
> > > >
> > > >Checked & cleaned as many ground wires were accessable. Big one on
> > > >front of engine - back one by firewall - one big gouping connected to
> > > >the back of the head we could not really get at, but we just put them
> > > >on when installing the engine.
> > > >
> > > >Checked terminals at starter R & S + big positive cable.
> > > >
> > > >Got us stumped why the voltage reg wont kick in when on the vehicle.
> > > >On the bench - no problem!
> > > >
> > > >Where to look now?
> > > >
> > > >Thanks in advance!
> > > >Gil
> > > >
> > >
> > > If you check your output with a digital meter, what do you get? Your
alternator
> > > may very well be wasted even though it was "bench tested".
> > >
> > >
> > > Joe--ASE Certified Parts Specialist & 10th Ann.Club Tech Director
> > > '80 Carousel Red Turbo T/A, 26k orig.
> > > '79 "Y89" 400/4 speed 10th Ann. T/A, 57k orig
> > > '84 Olds 88 Royale Bgm 2 dr, 307 "Rocket" (lol), 141k and still
going....
> > > '80 T/A project car...
> >
> > My anologe vom is fairly close +-.25V by eye reading.
> > The alt output at big red terminl reads exaclty the same as the the dash
> >
> > Gil
>
> I'm a Ford man, so this GM stuff has got me stumped.
> I'd really like to get this thing on the road & not take it to a shop
> so I can pay them to guess like me.
> Any other idea's on what to try next?
> Please e-mail me also, Its hard to check all the groups.
> Thanks
>
> Gil

As someone else mentioned, make sure the alternator is grounded. I have
seen the brackets not ground a lot of times over the years on GM's. You
can check that by taking a booster cable and running from the battery
negative to the alternator case to see if it turns on.

My 86 Jeep runs the same GM alternator and it gets it's excite power
from the coil power wire just before the ballast wire (on the 12 volt
side).

I also have seen this same alternator have the wires switched on the
small white plug on the alternator. Some versions have the A and B
switched for some reason on different years of Jeeps anyway.

Maybe your harness is for the other version of the alternator and those
two wires are in the wrong places?

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Gil wrote:
>
> (Gil) wrote in message om>...
> > (Bigjfig) wrote in message >...
> > > >Subject: HELP! 86'Firebird 2.8 won't charge more than 12V
> > > >From: (Gil)
> > > >Date: 5/3/2004 12:42 AM Eastern Daylight Time
> > > >Message-id: >
> > > >
> > > >My Son swaped a bone yard 85 camaro 2.8v6 into an 86 Firebird.
> > > >Runs great for about 10 20 miniutes, untill volts drop down, down down
> > > >till she runs out of battery!
> > > >New Battery- New Alt (bench tested at 15V twice)
> > > >Voltmeter on dash says it starts up at 12V.
> > > >Battery checks the same 12V
> > > >Big terminal on Alt check same 12V
> > > >
> > > >All three points check the same readings, even as the volts start
> > > >droping down to about 7-8 volts. As it goes down you have about
> > > >2minites to compair & check points till she's dead.
> > > >
> > > >Charge Batt & away we go again for another 10-20 minites
> > > >
> > > >Checked & cleaned as many ground wires were accessable. Big one on
> > > >front of engine - back one by firewall - one big gouping connected to
> > > >the back of the head we could not really get at, but we just put them
> > > >on when installing the engine.
> > > >
> > > >Checked terminals at starter R & S + big positive cable.
> > > >
> > > >Got us stumped why the voltage reg wont kick in when on the vehicle.
> > > >On the bench - no problem!
> > > >
> > > >Where to look now?
> > > >
> > > >Thanks in advance!
> > > >Gil
> > > >
> > >
> > > If you check your output with a digital meter, what do you get? Your alternator
> > > may very well be wasted even though it was "bench tested".
> > >
> > >
> > > Joe--ASE Certified Parts Specialist & 10th Ann.Club Tech Director
> > > '80 Carousel Red Turbo T/A, 26k orig.
> > > '79 "Y89" 400/4 speed 10th Ann. T/A, 57k orig
> > > '84 Olds 88 Royale Bgm 2 dr, 307 "Rocket" (lol), 141k and still going....
> > > '80 T/A project car...
> >
> > My anologe vom is fairly close +-.25V by eye reading.
> > The alt output at big red terminl reads exaclty the same as the the dash
> >
> > Gil
>
> I'm a Ford man, so this GM stuff has got me stumped.
> I'd really like to get this thing on the road & not take it to a shop
> so I can pay them to guess like me.
> Any other idea's on what to try next?
> Please e-mail me also, Its hard to check all the groups.
> Thanks
>
> Gil

On Fri, 28 May 2004 13:02:27 -0400, "Refinish King"
> wrote:

>I think the web site is www.aldata.com and for like $25.00 you'll have
>access to every piece of diagnostic, and maintenance data for your car.
>Better than having a bunch of shop manuals, and what they don't have. Call
>the 800 number and they'll get it for you.

Close King, it's www.alldata.com



** To email a reply, please remove everything up to and
including the underscore in my email reply header.

Thank you kindly for the correction:

I like to help, not give out misinformation!

Sincerely,

Refinish King


"SgtSilicon" > wrote in message
...
> On Fri, 28 May 2004 13:02:27 -0400, "Refinish King"
> > wrote:
>
> >I think the web site is www.aldata.com and for like $25.00 you'll have
> >access to every piece of diagnostic, and maintenance data for your car.
> >Better than having a bunch of shop manuals, and what they don't have.
Call
> >the 800 number and they'll get it for you.
>
> Close King, it's www.alldata.com
>
>
>
> ** To email a reply, please remove everything up to and
> including the underscore in my email reply header.

Mike Romain > wrote in message >...
> As someone else mentioned, make sure the alternator is grounded. I have
> seen the brackets not ground a lot of times over the years on GM's. You
> can check that by taking a booster cable and running from the battery
> negative to the alternator case to see if it turns on.
>
> My 86 Jeep runs the same GM alternator and it gets it's excite power
> from the coil power wire just before the ballast wire (on the 12 volt
> side).
>
> I also have seen this same alternator have the wires switched on the
> small white plug on the alternator. Some versions have the A and B
> switched for some reason on different years of Jeeps anyway.
>
> Maybe your harness is for the other version of the alternator and those
> two wires are in the wrong places?
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
>
> Gil wrote:
> >
> > (Gil) wrote in message om>...
> > > (Bigjfig) wrote in message >...
> > > > >Subject: HELP! 86'Firebird 2.8 won't charge more than 12V
> > > > >From: (Gil)
> > > > >Date: 5/3/2004 12:42 AM Eastern Daylight Time
> > > > >Message-id: >
> > > > >
> > > > >My Son swaped a bone yard 85 camaro 2.8v6 into an 86 Firebird.
> > > > >Runs great for about 10 20 miniutes, untill volts drop down, down down
> > > > >till she runs out of battery!
> > > > >New Battery- New Alt (bench tested at 15V twice)
> > > > >Voltmeter on dash says it starts up at 12V.
> > > > >Battery checks the same 12V
> > > > >Big terminal on Alt check same 12V
> > > > >
> > > > >All three points check the same readings, even as the volts start
> > > > >droping down to about 7-8 volts. As it goes down you have about
> > > > >2minites to compair & check points till she's dead.
> > > > >
> > > > >Charge Batt & away we go again for another 10-20 minites
> > > > >
> > > > >Checked & cleaned as many ground wires were accessable. Big one on
> > > > >front of engine - back one by firewall - one big gouping connected to
> > > > >the back of the head we could not really get at, but we just put them
> > > > >on when installing the engine.
> > > > >
> > > > >Checked terminals at starter R & S + big positive cable.
> > > > >
> > > > >Got us stumped why the voltage reg wont kick in when on the vehicle.
> > > > >On the bench - no problem!
> > > > >
> > > > >Where to look now?
> > > > >
> > > > >Thanks in advance!
> > > > >Gil
> > > > >
> > > >
> > > > If you check your output with a digital meter, what do you get? Your alternator
> > > > may very well be wasted even though it was "bench tested".
> > > >
> > > >
> > > > Joe--ASE Certified Parts Specialist & 10th Ann.Club Tech Director
> > > > '80 Carousel Red Turbo T/A, 26k orig.
> > > > '79 "Y89" 400/4 speed 10th Ann. T/A, 57k orig
> > > > '84 Olds 88 Royale Bgm 2 dr, 307 "Rocket" (lol), 141k and still going....
> > > > '80 T/A project car...
> > >
> > > My anologe vom is fairly close +-.25V by eye reading.
> > > The alt output at big red terminl reads exaclty the same as the the dash
> > >
> > > Gil
> >
> > I'm a Ford man, so this GM stuff has got me stumped.
> > I'd really like to get this thing on the road & not take it to a shop
> > so I can pay them to guess like me.
> > Any other idea's on what to try next?
> > Please e-mail me also, Its hard to check all the groups.
> > Thanks
> >
> > Gil


Ok, latest senerio:
Ran a good ground (jumper cable) from neg batt term to nice clean part
on alternator new alternator.
no luck still right at 11.8 volts when running.
Checked small plug at alternator- key on = 12volts on brown wire.
Checked fusable link in red wire behind passenger side headlight
(under air box) = OK by piercing wire casing with pins either side of
the link & ohm test.

Took alternator back to Autozone for another bench test = OK

now what???
Hmmmmmmmm

Still Gil
<but starting to shake!>

Gil wrote:
>
> Mike Romain > wrote in message >...
> > As someone else mentioned, make sure the alternator is grounded. I have
> > seen the brackets not ground a lot of times over the years on GM's. You
> > can check that by taking a booster cable and running from the battery
> > negative to the alternator case to see if it turns on.
> >
> > My 86 Jeep runs the same GM alternator and it gets it's excite power
> > from the coil power wire just before the ballast wire (on the 12 volt
> > side).
> >
> > I also have seen this same alternator have the wires switched on the
> > small white plug on the alternator. Some versions have the A and B
> > switched for some reason on different years of Jeeps anyway.
> >
> > Maybe your harness is for the other version of the alternator and those
> > two wires are in the wrong places?
> >
> > Mike
> > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > 88 Cherokee 235 BFG AT's
> >
> > Gil wrote:
> > >
> > > (Gil) wrote in message om>...
> > > > (Bigjfig) wrote in message >...
> > > > > >Subject: HELP! 86'Firebird 2.8 won't charge more than 12V
> > > > > >From: (Gil)
> > > > > >Date: 5/3/2004 12:42 AM Eastern Daylight Time
> > > > > >Message-id: >
> > > > > >
> > > > > >My Son swaped a bone yard 85 camaro 2.8v6 into an 86 Firebird.
> > > > > >Runs great for about 10 20 miniutes, untill volts drop down, down down
> > > > > >till she runs out of battery!
> > > > > >New Battery- New Alt (bench tested at 15V twice)
> > > > > >Voltmeter on dash says it starts up at 12V.
> > > > > >Battery checks the same 12V
> > > > > >Big terminal on Alt check same 12V
> > > > > >
> > > > > >All three points check the same readings, even as the volts start
> > > > > >droping down to about 7-8 volts. As it goes down you have about
> > > > > >2minites to compair & check points till she's dead.
> > > > > >
> > > > > >Charge Batt & away we go again for another 10-20 minites
> > > > > >
> > > > > >Checked & cleaned as many ground wires were accessable. Big one on
> > > > > >front of engine - back one by firewall - one big gouping connected to
> > > > > >the back of the head we could not really get at, but we just put them
> > > > > >on when installing the engine.
> > > > > >
> > > > > >Checked terminals at starter R & S + big positive cable.
> > > > > >
> > > > > >Got us stumped why the voltage reg wont kick in when on the vehicle.
> > > > > >On the bench - no problem!
> > > > > >
> > > > > >Where to look now?
> > > > > >
> > > > > >Thanks in advance!
> > > > > >Gil
> > > > > >
> > > > >
> > > > > If you check your output with a digital meter, what do you get? Your alternator
> > > > > may very well be wasted even though it was "bench tested".
> > > > >
> > > > >
> > > > > Joe--ASE Certified Parts Specialist & 10th Ann.Club Tech Director
> > > > > '80 Carousel Red Turbo T/A, 26k orig.
> > > > > '79 "Y89" 400/4 speed 10th Ann. T/A, 57k orig
> > > > > '84 Olds 88 Royale Bgm 2 dr, 307 "Rocket" (lol), 141k and still going....
> > > > > '80 T/A project car...
> > > >
> > > > My anologe vom is fairly close +-.25V by eye reading.
> > > > The alt output at big red terminl reads exaclty the same as the the dash
> > > >
> > > > Gil
> > >
> > > I'm a Ford man, so this GM stuff has got me stumped.
> > > I'd really like to get this thing on the road & not take it to a shop
> > > so I can pay them to guess like me.
> > > Any other idea's on what to try next?
> > > Please e-mail me also, Its hard to check all the groups.
> > > Thanks
> > >
> > > Gil
>
> Ok, latest senerio:
> Ran a good ground (jumper cable) from neg batt term to nice clean part
> on alternator new alternator.
> no luck still right at 11.8 volts when running.
> Checked small plug at alternator- key on = 12volts on brown wire.
> Checked fusable link in red wire behind passenger side headlight
> (under air box) = OK by piercing wire casing with pins either side of
> the link & ohm test.
>
> Took alternator back to Autozone for another bench test = OK
>
> now what???
> Hmmmmmmmm
>
> Still Gil


Ok.

Now look on the back of the alternator case for the plug numbers on the
white plug.

The small brown wire needs to be on pin 1 on the case side and the red
wire on pin 2.

I have seen the pin numbers on the alternator be opposite on some so the
brown and red wires need to be swapped in the plug. They come out of
the plug by pushing on a tab with a mini screw driver if needed.

The brown wire is on top on mine, my old tenant had his on the bottom.

Also the place to check for output is right on the alternator bolt for
the big red wire and on the alternator case. That gives a reading off
the alternator not off any wiring that might be bad.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Mike Romain > wrote in message >...
> Gil wrote:
> >
> > Mike Romain > wrote in message >...
> > > As someone else mentioned, make sure the alternator is grounded. I have
> > > seen the brackets not ground a lot of times over the years on GM's. You
> > > can check that by taking a booster cable and running from the battery
> > > negative to the alternator case to see if it turns on.
> > >
> > > My 86 Jeep runs the same GM alternator and it gets it's excite power
> > > from the coil power wire just before the ballast wire (on the 12 volt
> > > side).
> > >
> > > I also have seen this same alternator have the wires switched on the
> > > small white plug on the alternator. Some versions have the A and B
> > > switched for some reason on different years of Jeeps anyway.
> > >
> > > Maybe your harness is for the other version of the alternator and those
> > > two wires are in the wrong places?
> > >
> > > Mike
> > > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > > 88 Cherokee 235 BFG AT's
> > >
> > > Gil wrote:
> > > >
> > > > (Gil) wrote in message om>...
> > > > > (Bigjfig) wrote in message >...
> > > > > > >Subject: HELP! 86'Firebird 2.8 won't charge more than 12V
> > > > > > >From: (Gil)
> > > > > > >Date: 5/3/2004 12:42 AM Eastern Daylight Time
> > > > > > >Message-id: >
> > > > > > >
> > > > > > >My Son swaped a bone yard 85 camaro 2.8v6 into an 86 Firebird.
> > > > > > >Runs great for about 10 20 miniutes, untill volts drop down, down down
> > > > > > >till she runs out of battery!
> > > > > > >New Battery- New Alt (bench tested at 15V twice)
> > > > > > >Voltmeter on dash says it starts up at 12V.
> > > > > > >Battery checks the same 12V
> > > > > > >Big terminal on Alt check same 12V
> > > > > > >
> > > > > > >All three points check the same readings, even as the volts start
> > > > > > >droping down to about 7-8 volts. As it goes down you have about
> > > > > > >2minites to compair & check points till she's dead.
> > > > > > >
> > > > > > >Charge Batt & away we go again for another 10-20 minites
> > > > > > >
> > > > > > >Checked & cleaned as many ground wires were accessable. Big one on
> > > > > > >front of engine - back one by firewall - one big gouping connected to
> > > > > > >the back of the head we could not really get at, but we just put them
> > > > > > >on when installing the engine.
> > > > > > >
> > > > > > >Checked terminals at starter R & S + big positive cable.
> > > > > > >
> > > > > > >Got us stumped why the voltage reg wont kick in when on the vehicle.
> > > > > > >On the bench - no problem!
> > > > > > >
> > > > > > >Where to look now?
> > > > > > >
> > > > > > >Thanks in advance!
> > > > > > >Gil
> > > > > > >
> > > > > >
> > > > > > If you check your output with a digital meter, what do you get? Your alternator
> > > > > > may very well be wasted even though it was "bench tested".
> > > > > >
> > > > > >
> > > > > > Joe--ASE Certified Parts Specialist & 10th Ann.Club Tech Director
> > > > > > '80 Carousel Red Turbo T/A, 26k orig.
> > > > > > '79 "Y89" 400/4 speed 10th Ann. T/A, 57k orig
> > > > > > '84 Olds 88 Royale Bgm 2 dr, 307 "Rocket" (lol), 141k and still going....
> > > > > > '80 T/A project car...
> > > > >
> > > > > My anologe vom is fairly close +-.25V by eye reading.
> > > > > The alt output at big red terminl reads exaclty the same as the the dash
> > > > >
> > > > > Gil
> > > >
> > > > I'm a Ford man, so this GM stuff has got me stumped.
> > > > I'd really like to get this thing on the road & not take it to a shop
> > > > so I can pay them to guess like me.
> > > > Any other idea's on what to try next?
> > > > Please e-mail me also, Its hard to check all the groups.
> > > > Thanks
> > > >
> > > > Gil
> >
> > Ok, latest senerio:
> > Ran a good ground (jumper cable) from neg batt term to nice clean part
> > on alternator new alternator.
> > no luck still right at 11.8 volts when running.
> > Checked small plug at alternator- key on = 12volts on brown wire.
> > Checked fusable link in red wire behind passenger side headlight
> > (under air box) = OK by piercing wire casing with pins either side of
> > the link & ohm test.
> >
> > Took alternator back to Autozone for another bench test = OK
> >
> > now what???
> > Hmmmmmmmm
> >
> > Still Gil
>
>
> Ok.
>
> Now look on the back of the alternator case for the plug numbers on the
> white plug.
>
> The small brown wire needs to be on pin 1 on the case side and the red
> wire on pin 2.
>
> I have seen the pin numbers on the alternator be opposite on some so the
> brown and red wires need to be swapped in the plug. They come out of
> the plug by pushing on a tab with a mini screw driver if needed.
>
> The brown wire is on top on mine, my old tenant had his on the bottom.
>
> Also the place to check for output is right on the alternator bolt for
> the big red wire and on the alternator case. That gives a reading off
> the alternator not off any wiring that might be bad.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's

Mike,

That was it! now charging @13.5v!!!
hoohoooooooo!

Ya think somebody or some instuction sheet could could have mentioned
that when the Alt. was bought?

Car now F/S
not to bad for an 86 f'n bird.

Thanks all for your help!

Gil

Gil wrote:
>
> Mike Romain > wrote in message >...
> > Gil wrote:
> > >
> > > Mike Romain > wrote in message >...
> > > > As someone else mentioned, make sure the alternator is grounded. I have
> > > > seen the brackets not ground a lot of times over the years on GM's. You
> > > > can check that by taking a booster cable and running from the battery
> > > > negative to the alternator case to see if it turns on.
> > > >
> > > > My 86 Jeep runs the same GM alternator and it gets it's excite power
> > > > from the coil power wire just before the ballast wire (on the 12 volt
> > > > side).
> > > >
> > > > I also have seen this same alternator have the wires switched on the
> > > > small white plug on the alternator. Some versions have the A and B
> > > > switched for some reason on different years of Jeeps anyway.
> > > >
> > > > Maybe your harness is for the other version of the alternator and those
> > > > two wires are in the wrong places?
> > > >
> > > > Mike
> > > > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > > > 88 Cherokee 235 BFG AT's
> > > >
> > > > Gil wrote:
> > > > >
> > > > > (Gil) wrote in message om>...
> > > > > > (Bigjfig) wrote in message >...
> > > > > > > >Subject: HELP! 86'Firebird 2.8 won't charge more than 12V
> > > > > > > >From: (Gil)
> > > > > > > >Date: 5/3/2004 12:42 AM Eastern Daylight Time
> > > > > > > >Message-id: >
> > > > > > > >
> > > > > > > >My Son swaped a bone yard 85 camaro 2.8v6 into an 86 Firebird.
> > > > > > > >Runs great for about 10 20 miniutes, untill volts drop down, down down
> > > > > > > >till she runs out of battery!
> > > > > > > >New Battery- New Alt (bench tested at 15V twice)
> > > > > > > >Voltmeter on dash says it starts up at 12V.
> > > > > > > >Battery checks the same 12V
> > > > > > > >Big terminal on Alt check same 12V
> > > > > > > >
> > > > > > > >All three points check the same readings, even as the volts start
> > > > > > > >droping down to about 7-8 volts. As it goes down you have about
> > > > > > > >2minites to compair & check points till she's dead.
> > > > > > > >
> > > > > > > >Charge Batt & away we go again for another 10-20 minites
> > > > > > > >
> > > > > > > >Checked & cleaned as many ground wires were accessable. Big one on
> > > > > > > >front of engine - back one by firewall - one big gouping connected to
> > > > > > > >the back of the head we could not really get at, but we just put them
> > > > > > > >on when installing the engine.
> > > > > > > >
> > > > > > > >Checked terminals at starter R & S + big positive cable.
> > > > > > > >
> > > > > > > >Got us stumped why the voltage reg wont kick in when on the vehicle.
> > > > > > > >On the bench - no problem!
> > > > > > > >
> > > > > > > >Where to look now?
> > > > > > > >
> > > > > > > >Thanks in advance!
> > > > > > > >Gil
> > > > > > > >
> > > > > > >
> > > > > > > If you check your output with a digital meter, what do you get? Your alternator
> > > > > > > may very well be wasted even though it was "bench tested".
> > > > > > >
> > > > > > >
> > > > > > > Joe--ASE Certified Parts Specialist & 10th Ann.Club Tech Director
> > > > > > > '80 Carousel Red Turbo T/A, 26k orig.
> > > > > > > '79 "Y89" 400/4 speed 10th Ann. T/A, 57k orig
> > > > > > > '84 Olds 88 Royale Bgm 2 dr, 307 "Rocket" (lol), 141k and still going....
> > > > > > > '80 T/A project car...
> > > > > >
> > > > > > My anologe vom is fairly close +-.25V by eye reading.
> > > > > > The alt output at big red terminl reads exaclty the same as the the dash
> > > > > >
> > > > > > Gil
> > > > >
> > > > > I'm a Ford man, so this GM stuff has got me stumped.
> > > > > I'd really like to get this thing on the road & not take it to a shop
> > > > > so I can pay them to guess like me.
> > > > > Any other idea's on what to try next?
> > > > > Please e-mail me also, Its hard to check all the groups.
> > > > > Thanks
> > > > >
> > > > > Gil
> > >
> > > Ok, latest senerio:
> > > Ran a good ground (jumper cable) from neg batt term to nice clean part
> > > on alternator new alternator.
> > > no luck still right at 11.8 volts when running.
> > > Checked small plug at alternator- key on = 12volts on brown wire.
> > > Checked fusable link in red wire behind passenger side headlight
> > > (under air box) = OK by piercing wire casing with pins either side of
> > > the link & ohm test.
> > >
> > > Took alternator back to Autozone for another bench test = OK
> > >
> > > now what???
> > > Hmmmmmmmm
> > >
> > > Still Gil
> >
> >
> > Ok.
> >
> > Now look on the back of the alternator case for the plug numbers on the
> > white plug.
> >
> > The small brown wire needs to be on pin 1 on the case side and the red
> > wire on pin 2.
> >
> > I have seen the pin numbers on the alternator be opposite on some so the
> > brown and red wires need to be swapped in the plug. They come out of
> > the plug by pushing on a tab with a mini screw driver if needed.
> >
> > The brown wire is on top on mine, my old tenant had his on the bottom.
> >
> > Also the place to check for output is right on the alternator bolt for
> > the big red wire and on the alternator case. That gives a reading off
> > the alternator not off any wiring that might be bad.
> >
> > Mike
> > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > 88 Cherokee 235 BFG AT's
>
> Mike,
>
> That was it! now charging @13.5v!!!
> hoohoooooooo!
>
> Ya think somebody or some instuction sheet could could have mentioned
> that when the Alt. was bought?
>
> Car now F/S
> not to bad for an 86 f'n bird.
>
> Thanks all for your help!
>
> Gil

You are welcome.

It is a strange one though isn't it?

I figured this out by helping folks with Jeep wiring. Jeep uses the GM
alternator for a mess of years and with all the mixing and matching
folks do on old vehicles...

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's