Ok, As you can see i have an '86 f-150. It has the stock 5.8L H.O. $bbl. Carb and the Stock 100 Amp Alternator w/ External Regulator. Now i have been having problems with the battery charging. I tested the battery when charging and i get 12.4 - 12.6 volts. when the truck is off and i test the battery i get 12.1 - 12.2 volts.
Now i know that when the battery is charging it should be chaarging anywhere from 13.5 to 14.5 volts. So, i went and had the alternator tested at thrre different places and all three said it was good. this is the part were it gets tricky. I went out and bought three external regulators for it. the cheap one, the top of the line one and the stock oem matching one. while replacing the regulator the ignotion key was off and in my pocket and battery was disconnected. Unplugged the wire harness and replaces the regulator, plugged in wire harness, reconnected battery then started engine. Now one would think that this would solve the problem. But al three new regulators will not charge my battery. as a matter a fact when i check my battery while engine is running i get out of all three regulators a reading of 11.7 - 11.9 volts. i turn off my engine. and recheck my battery and i get 12.1 - 12.2 volts. so, i reinstalled my old regulator.

I really need some help figuring this one out Guys and Gals. I checked the wire harness and all things look good tested all wires and am getting no shorts of any kind. Please help!!!

 

I know you checked the wires for shorts, but did you check the wire for voltage that excites the alternator? I think it is white with a red stripe no matter if the alternator is internal or external regulator.

 

Kinda sounds sexual but in a morose kind of way....

 

This coming from a man in a bra?

 

Quote:

Originally Posted by bghnkinf250

This coming from a man in a bra?

Bwahahahahahaha!!!!!!

I'm gonna have to explain the bra thing someday, I wonder if Scott will let me
add to my post in the Mug Shots thread.

 

Really, there is no need to. Everybody has their hobbies...is it awkward in here or is it just me?

 

Wow, I usually have a wise crack for just about anything but you guys have me at a loss for words. Nice job!

 

i have been having a similar problem with my 86 and i just replaced the alternator the other day and now its runnin like your favirote song

 

check your grounds.make sure they are clean and tight.engine to cab,frame to engine,engine to fender to battery.

 

Have you checked the calibration of your meter???

Link to 1G external regulator wiring diagram: http://fordfuelinjection.com/public/...LT_wiring3.gif

 

Exactly my first thought. Also check where the voltage regulator attaches to the fender. This is how the regulator grounds, through the fender.

Does the lights flicker when the truck is running? etc...

Also does the truck have a factory ammeter, or warning lamps for the charging system?

 

It might not put out more than 12.5v at idle, bring it up to 1500 or 2k rpm and see what ya got

 

Yeah ... you got to get that alternator going pretty good ...

before it gets excited.

 

Very good point, and exactly right. You got rep points for that one.

 

Alright i figured part of it out. Even though the three shops said that my aternator was good. i decided to completely disassemble my aternator. I found that the main brushes were very badly worn and were wearing uneven. so i ordered a set of new brushes and reassembled the aternator and i am geting 14.5v now. but i have still to figure out why it will only work with the original regulator. the new ones still won't work.