Hi all,

had an alternator in car, but that fell apart. So for lack of something better I just used one from a ford fiesta. made some brackets so I could mount it, but it never charged during idle. So half dead battery and engine idling causes dead battery.
I only hooked up the wires as they were and that's how I was running it for over a year.

now I bought a 3wire replacement style alternator, but I can't get it to charge. I tried the same way (the only two wires that were there). one was battery, so I just shoved the other on field. I figured that the other one seemed to be plain ground, so the old alternator was probably one wire hookup.
So I checked wiring diagram and hooked up BAT+ of course to battery (selonoid side)
then i ran a temporary wire from the FLD of regulator to the FLD of alternator and hooked up ground. but still not charging. Now the odd thing is when it's running I get about 12V at BAT+ (depending on battery state) and on FLD only 10, but when I rev the engine the FLD goes down to 5V+ so it's exactly the opposite of I would expect (voltage going up), it's going down ?!
I'm gobsmacked. anyone any idea??? I changed the voltage regulator for the sake of it, and still the same. I could kick myself for not buying a one wire alt ...

Kalli

 

everybody is stupid after too many pints of smithicks

if all else fails pull alt and have tested.

 

I did that sober mind you :-) but checked your diagram I never hooked up stat. Will try that tomorrow. Hope that helps :-)

 

Kalli,
Playing off of 001's comments: In 65 they use different wiring (4 wire) for alternators than they do in the 66 (3 wire) and up models. The circuit change boils down to the idiot light vs ammeters. If you are maintaining the light configuration, wire it with the stator to the Vreg. If you are in the ammeter configuration , you need to move some things around at the Vreg.

 

thanks thanks and thanks again !!!!! i'm just having a cider on mustang001 and thanks for your comment jlg as it now makes a bit more sense now ...

the cable colors were all wrong so i started at volatage regulator and unwrapped and watched the cables change colors a fwe time ... well 45 years of hacking ...
what I did was field to field and stator to ground

I was originally going by the 66 wiring (thought it was the same), but then after 001s comment I checked on the 65 manual and it's like 001 said and now that you (jlg) mention the ammeter it makes perfect sense why it is that way (i run an idiot light)
So i just hooked up FLD to FLD, STA to STA (found the cut pieces) and it works PERFECT!

12.6V idling with headlights on, 13 without the lights and when revving I get solid 14V from around 1000rpm on upwards stable.

I just have to clean up all the wiring and I can go driving again, I was outside with Halogen lights, so now I'll have a couple of cans of cider to celebrate :-)

 

yeah...any excuse will work for a good pint cider
think i forgot what it tastes like.

 

Cool, glad you figured it all out!!

 

ya. delighted myself. had the car idle for 20mins and was standing next to it, nearly started dancing to the beat of the engine ... plap...plaplapp plap.plapp.plaplapp. haven't heard that for a while now. put a huge smile on my face. this weekend I'll swap the thermostat.
We finished my buddies Cuda. So first sight of sunshine the three of us will go on a spin. my car, a 1969 396 SS Chevelle, and a 1972 440 Cuda :-) that should make some noise