Charging issue with NB alternator control.
 

So I got my car all running well tonight, but the alternator is not charging. I bought and hooked up the controller just like in Abe's writeup, but for some reason it is not charging.

I hooked up the 12V signal from the ABS fuse in the engine bay (lol my car doesn't even have ABS), and there is power there verified by the multimeter. The case is grounded, and I have checked for continuance between the case and other parts of the frame.

But when I put the multimeter inline with the power wire it shows 0v, even though I know that it has a good power source. Also I have verified that it is hooked up to the proper terminal on the harness, 1O.

Any suggestions?

Abe scammed you. You're fucked.

J/K. I dunno. You're saying you measured power at the fuse box with a meter, but once you hooked this all up you're not getting power? Go back and see if you got power at the box. I'd also suggest putting an "add-a-circuit" in there to clean up the tap for power.

Pics of it wired up would help.

Get an NA alternator....I dicked with that setup forever and could never get it working.

Weird...that isn't what I want to hear.

Well, here you go for pictures.

Here is the mounting location (Trust me, it really is grounded well there):

Attachment 209764

Here is where I got my power from:

Attachment 209765

Any ideas?

Figure out why you aren't getting power to that box I suppose.

Im guessing he means the power wire to the alternator.

No, the box is getting power. If I put the multimeter inline I get 0volts, but if I take the power wire and ground it I get 12volts (well more like 11.5volts now).

Damn, just checked at the alternator, and now I am getting .616volts on the grey/red wire (1O), but still not charging. I let 1T hang just like in the writeup, but when I run it in megatune my voltages go from 11.6 and just start slowly dropping.

Any hints? I can't imagine my alternator would go out at the same time as this install, but my luck has been worse before.

Considering that NA alternators are a dime a dozen, why would you want to go through the trouble of setting up an NB alternator on an NA Miata?

Sorry, I just had to ask.


Tony

I can't remember exactly but I suspect 0.66V on 1O (assuming that's the input), isn't enough to get it charging.

Get a 330 to 1,000 ohm resistor from radio shack. Connect one end to 12V and the other to 1O, idle the engine, and check if it now charges.

Have to do a little reading, but ... power meter "in line"? To measure currents, you put the volt meter IN the circuit, meaning all the power goes through the meter. To measure voltage, however, you measure in parallel, meaning you touch the circuit, but the power does not go through the meter.

There are two wires which run to the altenator, I guess there's a chance you're on the wrong one? From my pics, you should be able to tell which wires are which, check their voltages at the altenator side, see if you're getting what you should get.
-Abe.

Yeah - I have put high voltages to it, and it does charge (overcharge) but I remember ~.6 volts is right. Maybe .7? Certainly not a lot.

Well, I took my alternator to Advance auto to have it checked out (to eliminate the possibility), and it looks like it could be on it's way out. It isn't dead, but it is only outputting 11 volts with the proper signal (9xxmV) whereas it is only getting 616mV from my setup.

I guess with both of those combined, it just isn't charging the system, unless anyone else has some input.

That sounds like a heck of a place to start. :-)

It sure would be nice to know for sure what caused it, but it does sound like maybe it's just old. Right now you're giving me fantasies about putting the regulator a diode away from ground but I don't think you need that, my car has been happily charing perfectly since I did this. If you need to get a new altenator, an NA one is fine as well. My friend did this and it's been working for him (I forget if there was a trick to mounting it or not), but to the purist in me, I prefer this box. Not to mention I would love to know if the pins suggested are the right ones so I can update my instructions. :-)
-Abe.

The pin (1O) is the correct pin, I verified that myself. I would have liked to have kept the NB alternator, but I found a NA one cheap. I your idea works, and my alternator was charging, but the combination of the lower ref signal voltage and the alternator taking a dump means that I was only charging at like 9volts.

But now I just have to find another damn switched 12v signal....