90stang50

When i first start my car the voltage is low until i rev it up a few times. I tested the alternator at kragen and it tested good. the voltage is good until i turn on the lights or blower motor or somthing like that. its got a new battery.

93 LX FiveO

how much does it drop?

how many amps is ur alt?

do u know the cold cranking amps on the battery?

90stang50

CCA IS 450.

14.5 VOLTS A IDLE. THEN WITH THE BLOWER MOTOR ON HI IT DROPS TO 13.3.

WITH THE HEAD LIGHTS ON IT DROPS TO 13.8.

threeg502

Does you car have underdrive pulleys on it? 13.8v shouldn't worry you much. 13.3 is cuttin it close.

90stang50

no it dosnt have underdrive pulleys. the 13.8 was what it was when i tested sometimes its lower when im driving and i stop at light or somthing and im sitting idle.

PRO50SC

I foyu still have the crappy 75 amp alt it's time to upgrade to the 3g alt set up.

Black Snake

yea what he said get a 94-95 alternator

musclemustang94

sound like you have resistance in the wire that goes from your alternator to your battery. the more it heats up the more resistance it will have in it. try replacing that wire and checking your batteries ground. If anyting is loose it will corode and get resistance in it. Look for resistance, burnt wires and bad grounds.

93 LX FiveO

my terminals are crap. ive had mine drop somewhere around 12 but the car kept alive. i thought it died so i turned the key back and noticed it was actually on. god damn jedi mind tricks lol

musclemustang94

you need around 10 volts to start a car. but once it is running it doesn't matter. your car will run, but the dead battery is going to draw a TON of amps from the alternator, make it run really hot, and eventually prematurely wear it out. if i were you i would have the batt checked out too. jus cuz its new dont mean it isn't bad. i have seen a car come into our shop on its 3rd walmart battery in 4 months.