New alternator
Thread Starter
Racer
Joined: Jan 2002
Posts: 419
Likes: 12
From: Land O Lakes Florida
New alternator
I replaced my alternator on my 82 with a 70 amp. I noticed when I turned the air on the the idle goes down and starts stumbling. Never happened with the other alternator.
Could the low amperage do it?
Could the low amperage do it?
Pro
Joined: Jul 2010
Posts: 545
Likes: 0
From: Jacksonville Fl
It your ac idler control is ether bad or not connected. It can be found under the idler screw on the driver side of the carb.
Melting Slicks
Joined: Jun 2005
Posts: 2,239
Likes: 74
From: Palatine, Peoples Republic of Illinois
St. Jude Donor '09-'10-'11-12-'13-'14-'15-'16-'17-‘18
NCM Sinkhole Donor
A vacuum leak will cause the idle to go up. Have you checked to see if the idle solenoid is working when the AC comes on?
Burning Brakes
Joined: Apr 2013
Posts: 926
Likes: 2
From: Castle Rock CO
Yes an altenator can cause this problem because the A/C unit lowers the idle when engaged. Depends on how much power your car draws and you can get a higher amp Altenator. 70 amps are great for most of these cars and your knew one might not be putting out enough amps. I would trade it in thinking it is defective and not providing the power it should. You may also want to have the A/C unit looked at because it might be causing a problem if this is the first time you fired it up this year. I see your in FLA but do not know what the temps are down there or how often you kicked on the A/C this year.
Last edited by MakoJoe; May 4, 2013 at 09:31 PM.
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Pro
Joined: Jul 2010
Posts: 545
Likes: 0
From: Jacksonville Fl
Yes an altenator can cause this problem because the A/C unit lowers the idle when engaged. Depends on how much power your car draws and you can get a higher amp Altenator. 70 amps are great for most of these cars and your knew one might not be putting out enough amps. I would trade it in thinking it is defective and not providing the power it should. You may also want to have the A/C unit looked at because it might be causing a problem if this is the first time you fired it up this year. I see your in FLA but do not know what the temps are down there or how often you kicked on the A/C this year.
Burning Brakes
Joined: Apr 2013
Posts: 926
Likes: 2
From: Castle Rock CO
We never know how long cars sit and his A/C unit might be causing the problem not the altenator which was why I suggested he have it checked also. I know under loads that an altenator can also cause the idle to drop. Just like when you jump start another car the providing car will lower in idle under the extra load. I am just providing information from my experiences 
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
A 70 amp alt should be more than enough for the car.
chances are you got a bad alternator.
Check it properly on a load tester like a VAT40.