Alternator problem
 

Allright guys, I killed my THIRD alternator within 1000 miles. I obviously have a serious problem here.... The first one was a reman that was on the car when I bought it. The second was a factory original off my parts car. Third was a new reman I just bought and it's already toast. I also replaced the battery when I put the new reman in. So, last time I drove the car was about two weeks ago and I noticed that the volt meter was pegged above the 16 mark. I drove it again today and it looks like the Alt is dead, I have 11.xx volts at the battery at idle. I have a new 4 gauge ground run from the block to the firewall, a new ground from the negative post to the frame, and a new ground from the negative post to the block. I did notice when I replaced the alternator last that the wire going to it is a bit corroded..could this be the root of my problem? If so, where does this wire go? I will gladly replace it with a 4 gauge wire.

Thanks!

very well could be, the corrision could cause a short and thus killing you aternator. check the wires going to the alt, they could be bad. it is possible that when you changed it, the wires on the inside broke and are shorting out. also replace as much of the wire as you can, use the same gauge as stock or the next size up, 4 gauge is overkill, hell most planes dont have that high.good luck

I like overkill :)

Well, rebuilt alts are a crap-shoot, but 3 alts in 1000 miles is a little excessive. I'm gonna go with some kinda short, or something.

Ah, I see this wire goes to the Battery + terminal. I actually already have that wire made in 4 Gauge. It just needs install...lots of projects going on at once, it's hard to keep track of them all. If anyone else has an idea on what could cause this please let me know.

If you have gone through three alts recently, I would be looking at install errors...

Like what did you set belt tension too???

Too tight and it burns up the bearings inside and wastes the alt. Setting the belt tension correctly is a must for the water pump and alt.

Just ran out and checked the last two for play in the shaft/ strang noises or resistence. both spin with ease and and neither have any play in the shaft so, I would say bearings are fine. I'm not sure what the belt tension is set at but, I've never had a problem with that before. I don't try to be He-Man when I put things together. I put it tight enough so the belt doesn't wobble around while the engine is running and that's tight enough for me.

You need the correct amount of belt deflection as per the shop manual.

Again if you have gone through three alts, I would bet it is because you are not setting the belt tension

Push in the center of the belt and measure how much it moves with a ruler. Short sections of belt should yield about 1/4". Long sections should yield about 1/2". A shop manual will explain it better.

http://www.powerstream.com/Wire_Size.htm
4 AWG is good for up to 60A on a power wire or 135A ground wire. But that's assuming you have 15 feet of wire.

Allrighty then...since you feel so strongly, I just ran outside and checked the belt deflection between the alt and main drive pulley. It's somewhere between 1/2" and 3/4" ...closer to 3/4" (it's dark outside and I don't have enough hands to hold a ruler, a straight edge, and a flashlight). Anyway, that's about on par with my Haynes manual. Other ideas?

yeah ive had that problem to...

right now im on my 4th and it seems to be doing ok

the first,second,and thirs was a blown regulator

the 4th was a under charge and no charge at all

so far the new ones holding but im feeling its a damn short and i hate wiringngngngng

You didn't mention a thing about the two wires going to the small plug at the back of your series four alternator. It sounds like that plug isn't even on the alternator, what with the high voltage at the gauge.

Black/White should have 12vdc when the key is to ON or better.

The White/Black should have approx 3vdc on it if the key is ON and engine OFF AND the plug is connected to the alternator. Start the engine and it should be 13-14 vdc.

Your wasting time adding gnds to the alt, block etc.

yes, the two prong plug is plugged in...This is for the voltage regulator right? I have not checked the voltage at that plug. Also...is the voltage regulator built into the alt? I thought it was or I would have tried to replace it as well. So even if the alt is bad I should get the voltages stated above at the plug? That is....I should get 12V at the B/W and 3V at the W/B. Now...if the alt is BAD I will not get the 13-14V with the engine running yes?

The grounds added around the engine bay (2 new grounds and one replaced ground.) are to cure all my other strange issues. I have not run one to the Alt, nor do I plan to. I was planning on replacing the corroded wire that goes to the Alt terminal. I just wanted to confirm that it runs from there to the Bat + terminal first.

AHHHH...now maybe we're getting somewhere. I ran outside and checked the voltages at the plug in the back of the alt. With the Key in the ON position and the engine NOT running I have ~11.47VDC to the B/W and ~11.24VDC to the W/B. Can I assume this means that the voltage regulator in the Alt is BAD? or do I have a short?

Just checked the resistence between the Alt post and the bat + post It's 6.9 Ohms. The new 4 Gauge wire that will go in it's place is 0.4 Ohms. Can I assume this is the root cause of my Voltage regulator failure? Someone chime in before I go play Dr. Frankenstien.

kkk..I've been searching this for HOURS. Found these nifty little diagrams. Is the wiring diagram here accurate? I'm not really sure what I'm looking at here...The warning light relay eats 9VDC? otherwise how would I get 12VDC on R and 3VDC on L?

So...If my warning light relay is bad could that cause this and explain the presence of 11.24VDC on L? I'm not getting a warning light. If so does this mean I need a new CPU? I'm not exactly a wiz with a soldering iron.

I found this niffty little page out of the Free, Online FSM for series four cars.

The warning light relay in the CPU will not and most likely can not cause your problem. When at rest, the alternator puts a GROUND on the white/black wire to the relay in the CPU, which in turn pulls the relay IN and makes a circuit to the warning lights to make them all light up.

When the alt puts out, the gnd is removed from that wire and the relay relaxes causing the warning lights to go out.

The IMPORTANT wire is the BLACK/WHITE wire that should have switched 12vdc on it any time the key is to ON. IF that does not happen and the alternator is rotating, then somewhere down the road, and not all that far down the road, the voltage reg in the alternator will go tits up and you get to use your warraty once more.

ahhhhhhh I looked through the FSM but all I found was the diagram of the CPU broken down which showed the Alt warning relay on board C. I guess that explains why all the idiot lights illuminate when you have the key in the RUN position but the motor is not running. Everything seems to check out ok then. I suppose I'll check the wiring to the B/W and make sure there are no loose connections. I'll also replace the line from post B to the main fuse and see where that gets me but...6.9Ohms isn't really that bad is it? Maybe I've just had shitty luck :(

Allright boys and girls I'm still having this issue... partly because I haven't had a lot of time to deal with it since I put the new alt (#4) in. Anyway... I now have 0.7V to (W/B) and ~12.2V to (B/W) with the key in the on position and the car off. I also have 15.5V to (W/B) and 14.6 to (B/W) with the engine running. There is about 12.5V at the battery with the engine off and 15.2V at the battery with the engine running. I am under the impression that anything over 15V is bad news so if anyone has a suggestion I would appreciate it. Do you guys think this is just a product of poorly remaned alts with shitty voltage regulators?