Alternator voltage drops when revved

[svrtlost]

i just replaced the alternator on my 1g now at idle it reads 14.4 at the battery but when revved voltage drops to 13 or 12.7 and my alt ight and battery light kick on. any help would be much appreciated

 

[Gary 420A RS]

check the tension on the belt for your alternator.. keep the car off and check the voltage on the battery look for 11.5-12 volts.

crank it over and check for the voltage..of best 14.2 anything more and your belt is too tight. 14.0-14.2 is when everything is at its best. so check the belt.. good luck

 

[luv2rallye]

...check for the voltage..of best 14.2 anything more and your belt is too tight.

Too high a voltage is never due to too tight a belt! (although too low a voltage can sometimes be due to too loose a belt). Too tight belts just run the belt or bearings in the alt or pulleys.

For your voltage dropping when revved problem check your battery and alternator cable terminals (both ends) for corrosion, dirty, not tight and the cables themselves for old, cracked, etc. Any resistance due to these will drop the voltage at the battery (across the cable). Measure the voltage right on the alternator's big post while revving. If it rises, that is your problem. If it decreases you most likely have a bad alternator (many "new" alts, usually rebuilts, are bad) - take it back.

 

[svrtlost]

belt tension is good; battery is new.... my issue is when the motor increases anywhere past 1500rpm voltage from the alt drops to 12.7(which is roughly what the battery fully charged is. idle=14.5 1500rpm=12.7. Also the batt,brake and alt light also come on in the dash. kinda baffled , starting to think that maybe i'm grounding out somewhere

Thanks for responding

 

[blackbyrd]

Sounds like your regulator is probably going.
http://www.dsmtuners.com/forums/showthread.php?t=242857
Let me guess, you got it from autozone?
Did you check all of your connections again?
I'm not sure what there alternators tests exactly, but you might want to bring it back there and test it.
And if it's bad, get your money back and take your buisness elsewhere, you'll have nothing but troubles(well for 75+% of the people who've gotten them)