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

If we were in the days of outhouses:

Sears catalogs were worth something for the purpose that you would use it for in an out house. I shudder to say, Haynes wouldn't even be good for that!

Refinish King

Reply to
Refinish King
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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

snipped-for-privacy@cin.net

Reply to
Gil

What are you using to measure the voltage? 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...

Reply to
Bigjfig

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
Reply to
Mike Romain

Anologe VOM. It matches fairly close to the volt gauge on the dash.(see previous post) Its got a mirrored scale & needle that you have to be lined up with on you eye sight ok? so error is +-.25 volts? Its the old fashon kind. I opened up the hood on my Lincoln LSC & read 13.5 volts with lights on. Its not the meter.

Reply to
Gil

alternator

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

Reply to
Gil

Your alternator

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
Reply to
Mike Romain

Your alternator

Well, the only thing I'm wondering now is, the volts are not droping back down to around 12.5,only for a r short time after the first start. After that its staying up at 13.5+, even with all acc. off. Hmmm. maybe be overcharging now? getting a draw somewhere? or we weakened the battery by draining it down to many times? So far its running & the kid has not called home to come & get him.

Thanks Again!

Gil

Reply to
Gil

Dropping down to 12 would mean a problem. 13.5 volts is about right in most cases. Usually should be between 13 & 14 volts from the alternator I think.

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Reply to
SgtSilicon

That sounds normal. Depending on the state of the battery, my alternator varies on the gauge between 13 and 14.5 volts.

Mike

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

Great catch on that Mike!

I couldn't have done that without having the parts in my hand in plain sight!

Congratulations for being a long distance diagnostician!

Refinish King

You Da Man!

Reply to
Refinish King

get? Your alternator

still going....

Actually...it better NOT drop back down to under 13 when running...or you have an issue again..

It sounds like its fine....

Reply to
CBhVAC:)

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