PCM Diagnostics & Tuning HP Tuners | Holley | Diablo

15.6V@WOT normal?

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Old Sep 24, 2012 | 01:36 PM
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Default 15.6V@WOT normal?

Just curious, since this seems excessive. During cruise I have noticed 14.8-15.8V without headlights, A/C, or anything else on, other then whats required.

I am also wondering if this voltage is taxing my HP. If so; is there a way to make changes by using HP tuners?
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Old Sep 24, 2012 | 02:36 PM
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It's abnormal, but there's always the question of "which
ground?" - PCM ground might or might not be the same
voltage as block ground (should be; assume nothing),
which is what the alternator refers its output to for
regulation. That wants checking.
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Old Sep 24, 2012 | 06:14 PM
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13.9 to 14.2v is normal no load voltage.
The first thing to check is the battery,a bad one can cause
a high charging voltage and testing the alternator on the car
is not a valid test w\o a known good battery. One thing for
sure is the battery won't live long at 15+ volts.
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Old Sep 24, 2012 | 07:40 PM
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Originally Posted by sreve
13.9 to 14.2v is normal no load voltage.
The first thing to check is the battery,a bad one can cause
a high charging voltage and testing the alternator on the car
is not a valid test w\o a known good battery. One thing for
sure is the battery won't live long at 15+ volts.
Great.. I just put a red top in back in June, so I don't want to hurt it.
Guess I will be checking for lose/bad grounds.


The good: Might have found a few more HP
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Old Sep 25, 2012 | 11:36 AM
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Bad battery current sensor (BCS). I am now@13.6V when cruising and 13.2@ idle.
Drops to 13.5V@WOT.
This was recorded with no additional load.
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