ok so I've burned up 5 alternators and I dont know why. the wiring seems but but the volt gauge on the dash reads almost at 18 volts.

any idea as to what could cause this?

 

depending on the alt, there is different wiring - truck's use one setup, ls1 fbodies another. what specific (year, model, etc) alt and wiring did you go with?

 

its all a 99 fbody setup, also i checked the turn on wire and it reads 10.2 volts which is normal

 

I believe the LS engines use the PCM to energize the alternator, is this correct? Unless the earlier versions still require the resistance to get it energized. Somebody correct me if I'm wrong. I know the LT engines required some resistance to get the alt to start charging.

 

yea it gets it from the PCM, Pocket where are you!!!

 

so all i found online anywhere says tat wire should only get 5 volts...so why the hell is mine getting 10.2 volts?

 

a 10.2 volt reading is actually about right. something is causing the regulator to hang open on yours

 

That's what I thought but its the 5th one. The volt gauge on the dash sits around 16-17v and everything I read says the alt wire should only have 5v on it and to put a 470 ohm resistor on the wire on use a truck alt

 

a 470ohm resistor is correct, but it doesn't drop it to 5 volts. if it had too many volts going to it, it'd just burn up the diodes, but that isn't the case here. where are you getting the alternators from? anyway to test on another vehicle prior to installation on your car?

 

3 of them were autozone remans but those are junk anyway. the other 2 were high output 160amp new that i got online

 

 

If you've got voltage, then the problem is the alt, not the wiring. FWIW, I went through 4 bad advance auto alts before demanding my money back. I coughed up $25 extra and got a new AC delco alt from rock-auto which hasnt skipped a beat

 

what does your volt gauge sit at when its running?

 

Just past 13v, approx 14.4v where it should be charging to

 

Mine too, somewhere around 14v

 

yea mine sits at 16-17v this is blowing my mind

 

Serious overcharge there

How is the connector wired in? To the PCM or through a resistor to constant power?

 

i tested the voltage at the battery with it running and i get 14.4v which is normal but the volt gauge on the dash reads 16-17v which is weird.
i have it wired to the PCM with a 470ohm resistor in line. it didnt have the resistor before. i put it in there to see it it would fix the problem

 

The resistor is for carb conversions not running a PCM or 97-98 PCMs because they dont have a provision for alt control. Find another cheap gauge cluster from a V6 or whatever you can find to retest the system. A bad gauge is nothing new, but if you really do have that high of voltage, you risk damaging things

 

i put my multimeter on the battery and it runs at 14.4 volts its just the cluster showing 16-17v for some reason. the cluster did the same thing in the 99 ss it came out of before i pulled it but then again the alt was bad when i pulled it anyway. this is just irritating the hell out of me.

 

found the fix to my issue. i went and got a DR44G alternator off a 2006 silverado. Its the heavy duty truck alt with the bigger case and heavy duty internals. it fits fine all i had to mod was shaving the bottom of the case a little to clear the pitman arm but it charges great and doesnt hit anything. the brace from the k member to the body had to be removed. it had a 2 wire plug instead of the 4 wire plug i had. all i had to do to make it work was cut the 4 wire plug off and solder the brown wire on the 2 wire plug to the red wire on my harness. the gray wire is unused. i would recommend this to anyone having alt issues in an fbody.