1991 Alternator differences

['91 Polo Green]

Can someone enlighten me on the difference in the alternator mount(s) for 1991 models. I recently bought a 140amp, to replace my 124amp but it is way to large. I cannot find anything on "First" or "Second" production differences in application (Mounts). I did however see a blanket statement previous to that order that stated that "All '91's have 140amp alternators". Apparently that wasn't true! 

 

 

[dship]

My '91 Reatta is early production vin# 900183 (Dec '90).  It came from the factory with a 124 amp alternator.  I've never come across any documentation about '91's having 140 amp alternators.  But my '92 Riviera came with a 140 amp, though.

['91 Polo Green]

Thanks for your response Dship,

 

I couldn't find anything either. My best guess is that some major re-manufacturer assumed that all buick's from (Approx) 90-94 have the same 140amp alternator. 

Rockauto shows that the below units fit the '91's. But they couldn't because of the intake configuration. (Not enough room for the bigger alternators) 

I thought maybe I could upgrade to the larger amperage & ordered the Pure Energy # 7984601 because Rockauto listed it as fitting. Their mistake cost me money and considerable time. 

When i wrote to Rockauto to point out the mistake, they simple wrote back to tell me that I' had made the mistake. 

 

Here are their incorrect listings:

 

PURE ENERGY 7984601 {Click Info Button for Alternate/OEM Part Numbers} Remanufactured Info 
Second Production, w/ 140 amp alt.

 

REMY 20582 {Click Info Button for Alternate/OEM Part Numbers} Premium Remanufactured Info 
w/ 1:00 Alt Plug; 140 Amps

 

ACDELCO 3342391 {#19135949} Gold; Remanufactured; 140 Amp (Instant $7 Manufacturer Rebate on ACDelco   Info
Second Production, w/ 140 amp alt.

 

Does someone know if other Buick models, from those (Approx) years show "Second Production"

differences?

 

Also might someone have an idea why with a (New) battery & alternator, the system still goes completely dead after just 8-15min at idle? I have checked all the grounds and every other test I have come across to try and figure out the issue. My conclusion is that the 124amp alternator is just to small to run all the taillights, fog lights at the same time at idle - I'm sure one of you guys can comment on this - Thanks in advance!

['91 Polo Green]

Ps. All the major parts houses show that the larger 140amp alternators fit the Reatta's.

[Ronnie]

1 hour ago, '91 Polo Green said:

I have checked all the grounds and every other test I have come across to try and figure out the issue. My conclusion is that the 124amp alternator is just to small to run all the taillights, fog lights at the same time at idle - I'm sure one of you guys can comment on this - Thanks in advance!

I don't believe the 124 amp alternator being too small is the problem.  If you put a volt meter on the battery to check for voltage does it show the battery is charging? The voltmeter should read about 13.5 volts at the battery when the engine is running. Also, have you done the battery drain test on my website? How To Measure Battery Drain

[Bloo]

I don't believe any car needs 124 amps. I suggest following Ronnie's advice.

 

[handmedownreatta]

5 hours ago, Ronnie said:

I don't believe the 124 amp alternator being too small is the problem.  If you put a volt meter on the battery to check for voltage does it show the battery is charging? The voltmeter should read about 13.5 volts at the battery when the engine is running. Also, have you done the battery drain test on my website? How To Measure Battery Drain

the alternator is sized to run that plus the ac clutch,cooling fan and other things.your car is running completely off the battery.the alternator isn't charging it for some reason.

 

Edited November 27, 2021 by handmedownreatta (see edit history)

['91 Polo Green]

Hey guys, I found the source of the short after Ronnie's test procedure. It was the HVAC Control unit. As soon as I disconnected it the Amps dropped down.

 

I have replaced it now and all is well.

 

Thanks for your help once again,

Jerome

 

- May the path to your door always be downhill,

and may ye be an half an hour in heaven afore the devil knows your gone!