Voltage Issue!!!!! Battery or Alt?

[benzmansl65amg 10+ year member]

So I put a new HO alternator on. I have the two batts in my signature. Also, Big 3 done. It was doing fine about 14.1 at idle. Then All of a sudden when at idle my voltage drops to 11-12 volts. Which is obviously bad. But then when I go faster the voltage increases to about 13.7ish. Then when I put it in Park (in idle) the voltage goes up to about 13 and stays steady. When in drive idling it drops again. Until, I accellerate. It is really wierd.

Thanks in advance,

Joe

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[clouduz 10+ year member]

What gauge wire did you use to hookup the HO Alt?

 

[benzmansl65amg 10+ year member]

0 gauge wire for big 3 but like 12 guage for the turn on for the alt

 

[daboyfrumdabx 10+ year member]

Not sure which brands do and don't but a lot of HO alts have shitty idle output and only really do their job when you're on the gas.

 

[benzmansl65amg 10+ year member]

It is supposed to idle at 120 and peak at 220. Idk it is really frustrating.

 

[ahole-ic]

EDIT: Read more closely. If you're talking about with the system off, you have a bad alt.

 

[benzmansl65amg 10+ year member]

System off entire time

 

[benzmansl65amg 10+ year member]

bump

 

[AlterEgo99 5,000+ posts]

Could be the voltage regulator or ECM in your vehicle. If you want to ensure you get a constant voltage, check out a company like Missing Link Audio (http://www.missinglinkaudio.com/)...they sell voltage regulators that will override your ECM/PCM and ensure you get a constant voltage.