i put another starter on mine about 20 minutes ago, it didnt fix the charging, but it is allowing it to start without the battery being fully charged

 

Hi everyone,

I'm having similar probs with my '84 300-6 F150. Previously the wires to the alt burned up, so I replaced the alt, wiring and reg. I also ran all new cables to the solenoid, starter and battery. Essentially everything is new.

However, my battery voltage when running varies from 12.2V to 14.3V, and the idiot light stays on constantly. Occassionally the battery dies, maybe once a week I need to charge it. Does anyone know what the proper voltages should be at each of the regulator terminals. I know the battery should be about 13-14V if all is well, depending on load. I'm inclined to blame the reg, since the light is always on. Sparky, where is that resistor you show in your diagram posted above?

Thanks all,
Tom

 

SaintITC, I "think" the resistor is located near the lamp. I bet if you ran the S term on the regulator to a switched +12 source, your problem would be over. Also disconnect the I term wire.

 

we have mine fixed, on the voltage reg, there are 4 tabs, my wiring harness aonly used four, and i had the choke wire coming off the alternator just dangling, for no real reason i we put the choke wire on the top tab(the one not being used, put the harness on and BAM, it was charging like a champ, no problems since

 

Hey, I fixed my problem. I had a faulty reg which I believe killed my alternator as well - both have been replaced. And the regulator (a Borg-Warner unit) was faulty to begin with, since I remember measuring 14.6v with it when I originally replaced everything 3 months ago. The store I bought the reg and alt from (PepBoys) verified the faulty alternator, and replaced both under warranty.

My problem with troubleshooting this was with the alternator. The built in rectifier circuit, using solid state diodes, had reverse current flow leakage only when under load. So when disconnected from the battery, it would put out 14v, but as soon as I connected it again it would drop to battery voltage. This is why my battery would last so long between discharges - I would go 3 or 4 tanks of gas before the battery would die. I believe this was caused by the faulty regulator which was trying to maintain 14.6v on the battery at idle. I finally suspected the alt problem by measuring the resistance between the alt F terminal and the ground pin (with alternator disconnected). It should be between 2 and 6 ohms, I was getting 1.8 ohms. My replacement reads 4.8 ohms.

I made a completely new wiring harness for this, using 8 gauge fine multi-strand wire directly fom the Alt BATT term to the battery, and a second smaller wire from the battery to the regulator A terminal. I have the idiot light setup, with the wiring as shown by Sparky above, and these are the voltages I get at the regulator terminals:

F - 8.5v (idle)
S - 6.5v (idle)
A - 13.3v (idle) - 14.1v (1500 rpm, all acc's on)
I - 12.4v (varies slightly w/ engine speed and load)

I guess I shouldv'e measured F & S with full load as well, but... I hope this info helps others with this problem. Also, I have the 60 amp A/C alternator, and a 800 CCA battery, and my idiot light works again (now if I can only fix the idiot...)

 

Thanks for the feedback.