OK... I realize I am still a miata noob, but I have done a bunch of searching and can't find what I'm looking for exactly. Probably partially because 'NA' and 'NB' are too short for most searches, it makes it hard to find what i actually need.

I am looking to turbo mine... its a 99. I have a megasquirt unit, and im sure if you're into that stuff at all you know that 99's the alternator voltage is regulated by the ECU and can be an issue when going with MS. So what I've read is pretty much everyone either builds a custom circuit, external voltage regulator.. or swap in a NA alternator, as they are internally regulated. Everyone said alternator swap was the way to go..easy...cheap, etc, and that's what I did.

I was out and about today, about 15 mins into the drive I have the low voltage/battery light or whatever. I got the battery charged up at advance just to make sure I could get home.

Now that I am home I did some tests with the multimeter... now I am not good with electrical stuff, so keep that in mind but I'm not totally stupid with it either.

Car off.... voltage was 12.9 volts. Turn the car on... I am getting like 14.9. When I turn on everything I can... A/C, radio, lights, defrost, it jumps down to 13.x and then keeps dropping. With only A/C on, etc it drops, but a lot slower.

-I've never done this alternator test before so I'm not 100 percent sure what these results mean.
-Running stock ECU at the moment

What does the batt light signify exactly? Voltage below a certain threshold?

The car has been running forever and hasn't died yet. Right now it's running with everything on and I'm going to see if it it will die.

Am i getting the light because my battery is actually being drained, or just because the ECU is seeing something it's not expecting are my thoughts right now.

Thanks,

Aaron

Here is a video of it all

http://www.youtube.com/watch?v=vdH-XHF2Dkk

 

I know we installed an NA alternator on a 2000 that was running a TECII, because it wouldn't regulate. I talked to Nate Dog and Warren G and they said an NA alternator would regulate.

 

I'm gonna back up a second and make sure I am not forgetting or missed something really basic here. All the posts I came across made it sound like the swap was bolt on and super simple but maybe i am wrong.

this is for a msm, but does this apply to me as well?

http://www.clubroadster.net/vb_forum...d.php?p=608184

 

The swap is cake...bolt in, wire switched 12v to it (i forget which wire and dont have the diagrams available right this second though) and you're good to go.

I had to do this with mine because I couldn't get the add-on circuit to work right.

 

it probably is simple, im just stupid when it comes to electrical stuff. If anyone can provide specific, kindergarten level directions it would be much appreciated, lol.

I am looking at the diagrams right now trying to figure this out as well

edit: it sounds like what i linked before is what I need to do

 

ok ok, I think i figured it out, I was just under the wrong assumption that it was a direct swap in, sorry for my stupid questions. still new to miata stuff, its a **** ton of knowledge to try and learn all at once.

 

Where do you guys come up with this stuff.

 

ok yes it was very simple...it's all wired up right and working now.

i guess it was so simple and previously discussed at one point so no one even really mentioned in all the threads i searched lol. noob thread closed

that link i posted from CR.net is the same thing, just some different ecu pinouts as it's for msm

 

HAHAHAHA I've been lol'ing at this for 2 straight minutes.

 

I nominate this for quote of the month.

 

Thread bump, sorry.

I swapped in a 97 remanufactured alternator into my 05MSM yesterday because I could no longer stand the Hydra not being able to regulate voltage. After the swap, the car no longer stalls, it finally idles like it should, and overall seems to run much better.

But -I also get an intermittent battery light on the dash. Right after the swap, I noticed voltage was around 14.6-14.8V. I then disconnected my laptop and have been driving for a day seeing the battery light go on about every 2-5 minutes, stays on for about 20 seconds and then turns off. I am assuming that the light comes on because the voltage is higher than the supposed specified 13.5V? If voltage was low, then I guess I would notice the same crap happening when the hydra could not hold high enough voltage, so I assume this is not the case.

Does anyone know if the voltage from an 97 alternator would cause the dash battery light to come on? Is there a chance of damaging anything if voltage is around 14.8? If not, I assume there is no way to prevent this light from coming on and off other than pulling the bulb? (which I don't really want to do)

 

(Sent from phone via capitalism)

Its going to vary by load where the nb will stay more steady. You did the little wiring change required for the alt right?

 

Yep, I did the wiring per the FM instrucions: Grey/Red(3M) to 12V switched, Grey wire(4T) to Brown/Red(3U). I am "assuming" I did not screw up the wiring but have not gone back under the dash to verify.

 

(Sent from phone via capitalism)

Might double check it I haven't heard of thiis issue when doing it but I know the wiring is for the charge light

 

Probably so. I just thought it was interesting the OP was seeing the same type of issue and that maybe others had as well, and maybe found a solution. Wonder what I'll do if the wiring is correct? In any case, the car seems to be running just fine - much better than before the alternator swap.