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Discussion Starter #1
I got P0340 ff pcm, turned it off at the dealer then i followed some posts instructions here and went to check the alt + battery voltage.

- With engine off the battery showed 11.8v
- On idle engine the test showed 13.8v - with rpm on 3000 it didn't move.
- With a/c + radio + lights + projectors on, it showed 11.6v, with rpm on 3000 it didn't move.

We checked the 6 battery houses acid (with a sucking hand pump, dunno what its called) 5 houses went up to the "white level" and the 1 near the negative cable went up to the red level, meaning its dead.

Dealer said battery + alt need to be changed, (don't ask me about the price they asked coz you will tell me they are thieves)

Electrician said i should change the battery first then re-run the test before going and changing both.

I need to know how many amps is the battery for the GT (it;s not written on the current batt) so i can replace it with the right one. And if i should replace both batt + alt or just the batt for now.

Thank you,
Tony
 

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The stock alternator is rated 80amps @ idle,, 135amps @6000rpm ..



..
 

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Discussion Starter #4
replace the alt. it should be putting out around 14.2 even with all that stuff you had on.
Changed the battery today.

Old battery test: With a/c + radio + lights + projectors on, it showed 11.6v, with rpm on 3000 it didn't move.

New battery test: - With a/c + radio + lights + projectors on, it showed 12v, with rpm on 3000 it jumped to 13.8

Means alt charging, now 13.8 mans it's tired and also need replacement?
 
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