xtreme2own

hey guys! first post here. looking for a few answers,

I have a 1990 Mustang GT 5.0 and i purchased last week. When i bought it the guy had a brand new in box alternator for it, and said that, that was the reason the check engine light would illuminate about 30 minutes after normal driving. I took it to a shop (before purchase) and they said that the trouble codes were not listed in the computers memory. So, i bought the car, thinking it would be an easy fix.

I bolted in the new alternator. Put in a new optima battery (800CCA, 1000 CA). After four days, the battery amps on dash kept getting lower and lower, until today, when it actually would not start. My question is, what could this be? Where should I start? What should I look for...

Some things that have changed in the past few days:

Ive installed, pullys, including alternator pullys. I dont believe that this would lower the charging ability to where it kills the battery however. Especially when im not running a big stereo system.... yet..

New alternator. There are three wires to attach. You must cut out the harness and hard wire it, per aftermarket alt. instructions. There are three wires, a small white one, and two bigger black ones with orange stripes. I got the white wire right, but when connecting the two black ones i MAY have mixed them up? Instructions said just to connect them.... giving me the impression it did not matter.

The refurb alternator i purchased may be bad? Lifetime warranty so i doubt it.

These are the things ive changed. Also, the car had a rigged electric fan that is wired funny and needs to be cleaned up a bit. I plan on taking it to a shop but maybe you guys would know where to start touble shooting this issue? Or give me some ideas of what may have gone wrong?

Let me know, thanks in advance for all the help!!

blackbetty93

Well....was your alternator ever charging the battery? A simple look at the volt meter will tell you. You can run a car while draining the battery on a dead alternator(I had to drive home last night after mine crapped out at a friends)...If your volt meter sat low and steadily dropped your alternator was never working...

The easiest way to tell is to go to your local discount and have them test your battery and or alternator...

creekrat

Easiest was to see if alt is charging is to disconnect the bat while the car is running. If the alt is putting out , the car will continue to run, if not it will shut off.

mjr46

The alternator wouldn't turn a check engine light on but it will turn the battery light on.......if your concerned that you may of hooked up the wiring wrong....get your old connector and look at all the pins where it plugs in and see where each wire went on the old connector and transfer that same location to the new connector....Go to autozone and they can perform a simple alternator load test to see if the new alternator is even working....sometimes right out of the box new stuff doesn't work.

nhancedssp

i had the same problem last week. i went through 3 alternators from advance until i finally got one that worked. if it's not your alternator though you may have a short somewhere...

mjr46

have alt tested

mattdel

i can definately vouch for the recent alternator problems coming from parts stores.
i have spoken with quite a few people about this, and it seems that over the past 1 or 2 years, the companys that actually produce these part store alternators have been having numerous quality control problems.

Autozone is now required to test all new/reman'd alternators, in front of the customer, before they pay.