Anyone know about 1990s mazda miatas?

[FbodTrek]

This.
You should be 13.8-14.6.
You have a bad brush probably. Those early Miata alternators are relatively inexpensive, and the replacement is a piece of cake.

Hard to make a guaranteed diagnosis sight unseen, but i'd hook a voltmeter to the hot lead AT the alternator, if it's less than 13.5, it's junk, guaranteed.

My credentials are 12 years of being a "diagnostic technician" in Houston, fancy word for a mechanic who doesn't just swap parts

 

[zsiiKWaRRiorz]

fixed everything except the rubbing brake(not 100% sure its the brake, but its more than likely the culprit). It was the battery. we checked the cells, and 3 were dry, 1 more low. that explains the battery reading 12 volts, but not having enough juice to start it.

 

[zsiiKWaRRiorz]

@FbodTrek we checked the alternator after changing the switch and it was reading 13point something.

Thanks everyone for your input. It is much appreciated.

 

[FbodTrek]

Sounds good then. Any time you have an electrical problem, start with connections, go to grounds, then to testing the charging output voltage AT the alternator, then test battery under load with engine on (load is headlights on, stereo, A/C etc). Takes a few seconds if the meter is in your hands already.
glad you finally got it all worked out!

 

[zeke]

The air bag light is caused by bad capacitors in the airbag diagnostic unit or the clock spring inside the steering wheel. Miatas use a special battery. Oreilys can order one

 

[MRM]

I went through and replaced every fuse on a car with an "electrical problem" and everything magically worked. None looked blown. Try it.

 

[Ken Ford]

Probably toast and needs a V8 conversion. If you need a economy truck I have. Dodge dakota for trade!

LOL

 

[Cruisers460]

Miatas use a special battery. Oreilys can order one

Had to look this up the other day. In europe that special battery popped up as a riding mower battery. Found a guy who used the Wal-Mart mower battery in two Miatas. Seems the specs were the same. Just thought that was funny, if the car doesn't crank grab the mower battery!

 

[letusbuyyourcar]

Im wondering if someone could diagnose an electrical an problem.

here is a post i made from a different site explaining everything:

Ok, so i got a 1991 miata a couple of days ago. its having a problem charging the battery while driving. it has a new alternator showing 12.3 or so volts on idle. and it would start out driving good, but then after a while, the charge light would come on, and the air bag light would start blinking. (amount of time/ distance would vary). Upon cutting the car off, it would not start again until recharging the battery. we did a little research and found out that the ignition switch can be the cause, so we removed it and cleaned it. after reinstalling it, took it for a test drive, and those same to lights came on. when we got it home, it would not start. we've ordered a new switch, and are looking into getting the alternator replaced. any suggestions, ideas, or other possible solutions?

also, if anyone can help with this second problem: it makes an odd sound when moving backwards, even if its just rolling a little on a hill before you pull off. it sounds kind of like the lugs of a tire scrubbing the wheel well when turning tires that are too large too far. also, it only does it on the driver rear wheel.

I'm not a mechanic and electricals baffle me asid from installing a stereo. But if you own a Miata then you need to go to Planet Miata.com. It's a dedicated Miata salvage. They sell every part you need and cheaper than most other sources.

 

[kennyallen]

Sounds like a bad cell, or bad ground