Alternator keeps burning up

[richs88rocker]

So my 88 yj keeps burning up alternators.

Here are the specs
:89 chevy tbi with the painless tbi harness
:I am running a Ford Taurus electric fan wired to the low side, with the painless :fan relay kit. My voltmeter seems to stay right at about 13.5 then drops to 13 :when then fan kicks on seems normal to me but this is the third one.

Wiring on the alternator is as follows. Positive going to firewall block and then to battery, Sensing wire is wired to a switched hot by the fuse block.

That is pretty much the only draws on the system.

Any Ideas please let me know??

 

[bobdog]

The sensing wire needs a resistor.

 

[anvil]

What alternator do you have, the old SI style or the newer CS? The SI series had a 2 wire connector. The big wire is the sense wire and needs full voltage. The other wire is the field current and needs either a resistor or a warning light in the circuit (30 to 60 ohms IIRC). No resistor or light in the field circuit could burn up alternators. The newer CS alternators work about the same, but they have a 4 wire connector.

If you are buying Autozone or checker rebuilt alternators that could also be your problem. I've had several of them go bad on me in a row. Finally paid for an AC Delco and I've been running fine since! Goodluck

 

[richs88rocker]

Gremlins....

Hey, Thanks for the feedback, So it is the single wire unit, It is from Car Quest, The supposed top of the line unit (remand in Mexico) I am trying the Diode inline, Seemed fine for the first hr, and now my voltmeter fluctuates between 13.5 volts at idle and spikes at 17 volts. at about 3000rpm. It seems i have another gremlin. I don't dare run it for long in fear of cooking all my other systems. so I am going to pull the alternator and have it tested to see what the deal is. I may just give up on the reman as you stated and by a factory replacement. It is not worth getting stranded for a couple bucks........