davecampbell34

New Member
I have had an 87 gn for about a year now. I brought it from FLA to CA. Won on eBay, and been very happy with it. But….. since I’ve gotten it, I’ve been chasing this electrical gremlin since time of purchase. I’ve gone thru multiple new alternators (3) and batteries (3).

The issue at the moment is that my voltage regulator inside the alt does not work after a lengthy drive, that's what I believe anyways. I’ve taken two alt into autozone (one that is currently being used and one I believed to have been "cooked" or ruined by the gremlin) and had them test them. The test for the one previously inside, came back that it was indeed “broken” or defective. The current one I’m using the test came back fine. Note: they didn’t give me any paperwork for those two tests. So I put that good alt back in, picked up a new battery and everything was going ok. Till I took a lengthy drive of about 45-50min round trip.


Getting close to my house on the return trip, my voltage light came on in the dash, and it sounded like the car started to run lean. It didn’t sound like itself normally but wasn't something super noticeable. I got back to my house, and when I opened up the hood the battery was sweating. I checked the voltage meter and the battery was in the high 16v. You could smell the acid inside was cooking.


I’ve ran a few different tests for parasitic draws, and they come back that I don’t have one except! That sometimes when I test with the light, it will surge the light dimly, I’ll clear the test and do it again, and it will show no signs of a parasitic draw.

I’ve looked for “volt blasters” that I’ve read on some forums that could be the cause of this, but I haven’t found a volt blaster attached anywhere near the alt. It seems there’s a possible ground somewhere that could be shorting out? but I don’t understand why my voltage regulators are continually going out. Something seems to be “cooking” the batteries? Idk. I come from a long line of assemblymen in Detroit but they never passed shit onto me. So a lil amateurish in my mechanical skills, but willing to learn but also willing to accept my limitations.

If this problem is too big for myself I’m also interested if anyone knows a good tech mechanic around LA that doesn’t have too long of a waitlist? I see everyone recommended Lou on previous posts but I’d rather not tow it to Long Beach, and I think that might just be too far for me to drive with the risk of blowing up my battery and myself. Anyways, any help would be much appreciated. Been a fan of this site for the last year and gotten much help in other areas. Thanks
Dave
 

TurboBob

Resident mad scientist
Staff member
Post some pics of the alternator area. the volt boosting devices all work basically the same way, by tricking the alternator "Sense" input.

The stock Buick wiring does not use the sense input at all. other that that I do not believe its possible to make the alternator overcharge like that.

Do you have a voltmeter?
 

davecampbell34

New Member
Post some pics of the alternator area. the volt boosting devices all work basically the same way, by tricking the alternator "Sense" input.

The stock Buick wiring does not use the sense input at all. other that that I do not believe its possible to make the alternator overcharge like that.

Do you have a voltmeter?
Turbo Bob,

I will go to the garage and get some pics now. I do have a handheld volt meter. the one on the dash is just a light saying something is wrong with battery/votlage. Something is making my alt pump out extra voltage, just don't understand what that could be. ill go get some pics for this post.

Dave
 

davecampbell34

New Member
Ok so here’s a few pics. Lmk if these will do. I just noticed something as well. It looks like that red wire, near the connection to the alt, it looks like it’s been a lil melted. Could that be the source of this problem? Or is that just a symptom of this problem?
97781DC3-0286-40B6-832A-E54487128C09.jpeg
2F56170A-53BC-4E35-AA99-0ED68C55C7DB.jpeg
211D1FA7-A6B9-446F-B92F-369F0F1915DA.jpeg
 

zapp240

Active Member
installing a Scanmaster should be your first priority. It is used for basic troubleshooting and diagnostics for our cars. It will give you a Volts readout that you can monitor. That red wire is a hotwire kit that supplies voltage to the fuel pump, bypassing the 35 year old wiring that usually causes trouble supplying enough power to the pump.
 

davecampbell34

New Member
installing a Scanmaster should be your first priority. It is used for basic troubleshooting and diagnostics for our cars. It will give you a Volts readout that you can monitor. That red wire is a hotwire kit that supplies voltage to the fuel pump, bypassing the 35 year old wiring that usually causes trouble supplying enough power to the pump.
I have a scanmaster installed, and have not noticed any variation on that when the battery was cooking last time I drove.
 

TurboWh1

Active Member
Is the Alt plug factory/original? Someone may have replaced it and depending on what pin has 12v at the plug could be causing your over charging issue. That plug is a problem more than likely even if original due to terminal tension. I would also highly recommend new battery cables from Casper's Electronics as well.

In regards to your alternator, it's not a stock piece, meaning different stator. Do you have a local alternator/starter repair shop that could check your alternator? Many of the aftermarket pieces are not good for our cars. When remanufactured, they only replace what is bad and reuse the rest The charging system is CRUCIAL for optional performance on a Turbo Buick:)
 

davecampbell34

New Member
Is the Alt plug factory/original? Someone may have replaced it and depending on what pin has 12v at the plug could be causing your over charging issue. That plug is a problem more than likely even if original due to terminal tension. I would also highly recommend new battery cables from Casper's Electronics as well.

In regards to your alternator, it's not a stock piece, meaning different stator. Do you have a local alternator/starter repair shop that could check your alternator? Many of the aftermarket pieces are not good for our cars. When remanufactured, they only replace what is bad and reuse the rest The charging system is CRUCIAL for optional performance on a Turbo Buick:)
Thank you. That’s interesting. I don’t know if the plug is original but there are other aftermarket pieces on there, if I had to bet. I don’t think it’s the original plug. Autozone was the closest place I checked last time to get the alt checked, but I’ll do some deeper digging since they didn’t give me any paperwork with the test just a kid saying “says it’s all good”…

Gonna look more into this plug. Think that could be onto something. Look into ordering those new cables as well.
 

Pronto

Chaos is a ladder.
Aside from the hotwire kit what is that other wire attached to the hot stud? If you can find one of those shields for it that would could save you an unexpected zap.
 

Chuck Leeper

8/10's of a century!
Staff member
No drawing available for the alternator circuit.
However, it sounds like the "F" pin on the plug is getting hi volts and causing the alternator go full field...And the volts go nutz.
Turbo Bob?
 

davecampbell34

New Member
Check voltage at the excitation wire with key on. It’s the plug at the alternator. Should be less than 12v.
Ok, so update as of this evening. went to test the voltage on the alternator and the battery was completely dead. after the event of making it sweat and cook the other day, I wonder if it is completely cooked and ruined or just flat from a parasitic draw... was reading 0.67v. Its a brand new optima battery. Only driven a few times around the block, before it cooked on the longer drive, but also wasn't having any issues with it till that longer drive. I have it sitting on the trickle charger over night tonight. Probably take that to auto zone and get it replaced tomorrow as I believe it is wrecked, but I could be wrong, if it holds the charge then I will test the alt tomorrow and see if it starts, run some tests I guess and look at ordering that plug.

wondering, if besides ordering a new plug, ill need to get a whole new alternator again. Trying to find an auto tech that will test it near me tomorrow, but so far its only auto zone and they just give me a thumbs up or down, not a real print out of the analysis. appreciate everyones help, very awesome thanks.
Dave
 

~JM~

Wrinkled Member
Alternator info.

Interesting info on Kirban site below.
"Many of the aftermarket alternators do NOT have the proper size pulley on them. The proper size pulley where the serpentine belt rides against is 2.405 inches."

Check the clearance between the belt tensioner pulley & the A/C compressor mounts/bolts. The shorter TTA belt will provide more clearance.
 
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SFI Cutlass

Active Member
Ok, so update as of this evening. went to test the voltage on the alternator and the battery was completely dead. after the event of making it sweat and cook the other day, I wonder if it is completely cooked and ruined or just flat from a parasitic draw... was reading 0.67v. Its a brand new optima battery. Only driven a few times around the block, before it cooked on the longer drive, but also wasn't having any issues with it till that longer drive. I have it sitting on the trickle charger over night tonight. Probably take that to auto zone and get it replaced tomorrow as I believe it is wrecked, but I could be wrong, if it holds the charge then I will test the alt tomorrow and see if it starts, run some tests I guess and look at ordering that plug.

wondering, if besides ordering a new plug, ill need to get a whole new alternator again. Trying to find an auto tech that will test it near me tomorrow, but so far its only auto zone and they just give me a thumbs up or down, not a real print out of the analysis. appreciate everyones help, very awesome thanks.
Dave
There is a great possibility that the battery could be toast. Battery’s are only made to be charged at around 14.6 to 14.7 volts max. If you had up to 16volts at the battery with the car not running more than likely you have an unstable battery and the cells could be bad. I still would like to know what the voltage is on the connector at the alternator with key on, car not running.
 

davecampbell34

New Member
Well thought it was fixed that new plug and the flex dash panel installed, and it may have fixed that overcharging issue… but I still have a draw on the battery happening…. Still searching for it.
 
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