alternator starts charging after 2500 rpm's not before ? please help i am stumped

[osborne looney]

2001 m/craft 5.7L weirdest thing i have come across yet !!! alt will NOT charge till after 2500 rpm's then it seems to be charging all the way down to idle -- until i shut it down -- then it starts all over again -- YES NEW LEESE NEVILLE ALT !!!! i am baffled -- stumped all wiring is good as well .NEW battery as well

 

[alldodge]

Is it a one wire alt or standard?
Do you have more then one battery? If so is there a battery switch, isolator or ACR?

 

[osborne looney]

Is it a one wire alt or standard?
Do you have more then one battery? If so is there a battery switch, isolator or ACR?

standard 3 wire positive ground and exciter one battery no batt switch isolator either

 

[MH Hawker]

thats how they work so its normal

 

[alldodge]

Will agree they need to bring up the rpm the first time to start working but normally its in the 1500 range, going to 2500 is different from what I normally see. Could also be your tach is a bit off. Don't know which model engine you have but have you check the voltage output, is it 14.5V during charging and is the battery at 100% ?

 

[osborne looney]

Will agree they need to bring up the rpm the first time to start working but normally its in the 1500 range, going to 2500 is different from what I normally see. Could also be your tach is a bit off. Don't know which model engine you have but have you check the voltage output, is it 14.5V during charging and is the battery at 100% ?

14.3 at full charge with 100% 12.6 volt on new battery -- i guess i will just have to rev it before taking off every time i start it -- thanks all