so i got the mean green 180amp alt and i replaced the belt and checked all the grounds. every thing is good from what i can see, if my xterra is at an idle everything is good but if i rev it, it pulses the more load i put on the alt the less it pulses and if i put a full load on it it will not pulses till its about 2400 rpm. idk what to do i need help.

How are your battery connections? A little corrosion can cause a lot of symptoms.

they r good iv cleaned them anyways, so i know there good

YOu might consider a dedicated auto electric repair shop in town for a paid diagnosis.

I know that's not much help, but the new alt isn't cheap, and I'd hate for it to die, or for it to potentially kill your battery or sensitive electrical systems on your truck.


It sounds like it's not being regulated well.. Have you double checked the install w/ any directions that it came with?

ok i guess ill have to pay.... grrrr, my red top is good and iv looked at every thing i could think of, im just out of ideas, to put it simply.

but its an alt its not diff from stock its just the internals are diff, its the same alt.

is the belt tension correct?

yep, and its a new belt the last one was pretty bad

How does the engine run when it's doing this?

Mindboggling. Wonder if it's ignition-related...

The alt on my wife's old chevy van pulsed like that. You could see it when the headlights were on. It lasted several years before the rectifier finally failed.

I suspect there is something wrong with the new alternator, sorry to say.

its fine ill send it back but it runs just fine and idk.... im so lost