Big 3 Problem....HELP!!!

[bigmack2007 10+ year member]

I have a mean green alternator i just put in my jeep grand cherokee. The voltage on it always sat alittle over 14.5. Today i did the big 3 in 0 gauge wire and now my voltage sits at 14.3 if i'm lucky. The only thing i can think of that i messed up on was i accidently grounded the power wire on the alternator casing and there were some sparks. Would this have damaged it somehow? Thanks in advance. any knowledge would be greatly appreciated.

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[NissanKicker 10+ year member]

Yeah bro.... You can't just accidentally Ground and Positive... Especially on your Alt....

But just incase:

1) Make sure your grounds are fully connected and touch RAW metal.

...

2) Make sure your Positive to Positive connect on you Alt is secure on it's post... Don't want it to be loose or on that rubber/plastic...

...

3) And check your Engine Block to Chassis connection... tight and secure.

 

[blackbonnie 5,000+ posts]

make sure everything is secure, its normally a loose ground

 

[bigmack2007 10+ year member]

alright so today my voltage was still dropping when i wasnt moving and it was going down to 13.4. I went to Autozone and got it tested and it read 45 amps at idle and 90 amps at 2000rpm. About an hour of driving later it seemed to have gone up to 14.5 or so and was idleing at like 70. I went to a different place so i dont know the max output. But after 8 hours of sitting in COLD weather i started it and the voltage is at 14.5 again. I'm hoping my alternator is alright after all. I'm gonna get it fully tested again tomorrow. Does anyone know any reason this could of happened?

 

[GMCJimmyslt2000 10+ year member]

hwo are u testing the voltage. DMM or just ur cars gauges

 

[timelessr1 10+ year member]

I'm not sure this is 100% your problem, but after doing research on a new Alt for my car, i realized that most HO Alt do not put out great power while at idle compared to stock units. Just a thought..

 

[bigmack2007 10+ year member]

Well I'm going by the dmm at autozone as well as my own dmm and my gage on the jeep. Today it measure 82 amps at idle with my radio on. It measured >99 amps at 2000 rpm. Would having electrical stuff on lower the reading? Anyway it seems to be doing better. My voltage was a 14.7 as well.

 

[mdillon 10+ year member]

you can always increase the size of the pulley so it will spin faster at idle, or set your idle to about 2000rpm