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Brock M

2007 gt500 electrical issue

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Driving my 2007, GT500 and got a charging system warning.    Limped half way home before the battery couldn't run the fuel pump and had to have a tow back.

I pulled the stock alternator, 17,000 miles, and bought a "replacement" at NAPA putting it in, much pain involved.

Drove a total of two times since, probably not more than 50 miles, took the car out last night and the charging system warning came on again.

before I changed it the first time it was reading no charge at idle, (11.9 V).  engine off read 12.1 V.    After installing new Alt. System showed 14.3 V. At idle.

All should have been good......

I really don't want to do this every week, any suggestions?

 

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Could be the factory cd changer draining the battery. Several of us has experienced the cd changer non-stop cycling even with the car off and keys removed. 

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At low RPMs, the alternator is not spinning fast enough to charge properly.  I had to change the pulley on the new alternator to increase its spin.  It’s been a few years so I don’t remember the size change but I did it  just enough such that the existing belt still worked.  Search  for undersized alt pulley.  I never had the problem again after swap.

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I noticed the new alternator pulley diameter is perhaps 1/4" smaller than the OEM.   I'll start there, checking at various RPM and get the battery tested as well.

Thank you.

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Had some time today to go back and review the alternator issue on GT500 2007.

Same thing, battery puts out 11.9 VDC, start the engine and at idle it is getting 11.4 VDC.   Clearly a non-charging alternator..... not bad for less than 50 miles on the new one.

Any additional ideas?

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Well let me just say my brain is going and I was wondering if I had remembered this backwards.  I started looking around past threads and if its more about the alternator going bad, it seems to be that the thought is the alternator is spinning to fast and is prone to going bad.  So the change is to a 10% or so under-drive pulley to reduce the spin for longevity but still be enough to charge the system.  And to still use the existing belt.   I now remember that's what i did due to having 2 alternators go bad. And that's why i had charging problems, the alternators were going bad due to over reving.    Google GT500 alternator problems, there's a ton of info our there.  Again, once I changed the pulley, have never had a problem since.  I track my car a lot too.  Sorry for the reversed memory!!

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I experienced alternator failure at 49k miles, swapped it out for a rebuilt from Advance Auto, no joy. Removed and took it back, they tested it, it failed. I fought for a refund, got it and purchased a rebuilt from Bennett, no problems since.

So, $#it happens. If I ever need to purchase another I will have them test the unit prior, to avoid the double PITA of install on all my vehicles.

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