Electrical Charging Issues

[94stangfan]

I had seen some wierd fluctuation in my charging a couple weeks back, so I pulled my alternator to have it tested and it failed.

I bought a remanufactured alternator to try and remedy the problem, but what I am experiencing now I don't have an explaination for.

The charging system works fine (based on the stock guage) when I am running the radio and driving during the day. (not using the AC)

If I turn the AC on, it causes the charge to drop a letter. I am normally (pun intended) between the r and M of NORMAL on that guage, but when I turn the AC on, it drops to between the O and R. This is concerning enough, but if I run the AC at idle like in stopped traffic and a stop light, it dropps down to the N. When I go again, it raises back up to between the O and R.

Is this possibly a bad remanufactured alternator? I am thinking the voltage regulator is probably bad on it, but wanted to get someone elses opinion since this really isn't my specialty. When I examined the remanufactured alternator, it had the old motorcraft voltage regulator on it, so it was reused. This is what is leading me to believe this.

Is it possible the battery is getting weak?

The reason I ask about the battery is that if I run with the lights on, it too will cause the guage to go down to between the O and R, but after a while it goes back to the R and M.

Thanks,

Keith

 

[94stangfan]

I am running stock pullies and stock radio. Everything is stock except I have Explorer heads and intake. It is a 95 GT Convertible.

 

[revhead347]

Very good chance you got a bad alternator. Did you swap pullies on the alternator, or did you just use the pulley that came with it? Reman alternators are sold with a random pulley because they are meant to fit on multiple cars. Is this happening at idle, or all the time? I would take the car to the place you bought it from. Most parts stores can run a charging test on the whole car with it running. If the voltage drops below 12 with the car running and everything on, then something needs to be fixed. If they knew that you just bought an alternator from them, and it's not charging on the car, and the parts guy witnesses it, it's tough for them not to give you a new one regardless of what the test bench says.

Kurt

 

[94stangfan]

basically it only happens at idle. The charging goes up when I am at driving speeds. The wierd thing about this is that this alternator only works on Mustangs and T-Bird/Cougar of various years. I don't think the pulley is any different from those cars.

I will try a different alternator. This one came from Autozone. It is the mid grade alternator. What they call their "Premium Reman" The next level is 100% new. I may ask if I can just upgrade to that and stop dealing with this problem. It is a $20 upgrade.

 

[revhead347]

Yeah, I don't think it makes much difference. The only thing they reuse on those rebuilts is the case itself. Dropping to O at idle generally isn't a problem. I would check the voltage off the battery at idle. If it's over 12 volts, then I doubt you will have a discharge issue. If it starts dropping to N or lower then it starts to be a problem.

Kurt

 

[94stangfan]

One would think that... Mine still had a motorcraft voltage regulator on it. So whomever rebuilt it didn't change it. I brought it back and swapped it with a new one and this one seems to be doing the trick. It sucks that this is my third remanufactured alternator from autozone. I finally got a non defective one.

 

[revhead347]

Good deal man. I went through 3 of them in a row one time. Each worked for about a week, and did the same thing yours did. One of them dropped below the N. That was when I was using my Mustang as a daily driver too.

Kurt

 

[95Vert383AOD]

I had the same issue and changed my alternator 3-4 times. I tried rebuilt and even went to an armature shop. Finally exhausted of time and funds i went to the junk yard and bought a $35 one because i needed to get to work. (At the time it was my Daily) 4 Years later and no issues with the junk yard alternator. I don't know why rebuilds are so crappy these days.

Chris

 

[94stangfan]

I really think they are designed to be crappy. In my case, if I didn't have a guage, I would not have known my alternator was not performing as it should. Most people have the warning light only and that will only go off when the alternator has either completely failed, or it is failing and you are about to lose power. Both are a kind of too late to do anything point. So if these big parts stores can make some money off of the battery light people then they do so banking on that the car won't be around more than a year or two with them and the new owner will need to buy a new one and the cycle continues.

I may be in a conspiracy theory here, but that is what I think at this point. I am so tired of changing alternators. Although, I am very good at it now.