Hi guys!

So I'm having a bit of a problem with what i think is alternator, or alternator related.

Backstory: Washed the car, started it up, started just fine - before driving anywhere, just having it idle, noticed smoke coming from generator area, smelled like what i would describe as "burnt electronics".
After a while, the smoke stopped, everything still working, but that's when i noticed my battery light was on. very faint, but on.

Now: Battery completely drained overnight. (Made sure i had no cabin lights switched on, or the one in the trunk etc.) Voltage at around 3V only. Will start and run "fine" when jumpstarted.
What i mean with "fine" is that after jumpstarting it the day after, with the battery being drained, my RPM needle started going from what it should read, and then dropping to zero, meanwhile, ABS light turns on and off. Car runs fine, no idling problem or anything, but it's not supposed to do that.

I suspect something became wet, that should not have been so. At around 3000rpm, the battery light no longer lights up - so higher rpm - more charge, no problem. So what could it be? I'm certain the car is dry now, the day after.

What could it be? Fanbelt slipping? Something wrong with alternator itself? Anyone have any idea?

My guess would be alternator, but best make some checks with a meter.

So, i will be replacing the alternator and the fanbelt/serpentine belt. (?) (Not sure what it's called, but might aswell replace it since it's atleast 5 years old.).

The alternators come in 70Ah and 90Ah for some reason - is there any reason to get a 70AH one?
Do i need to have a battery installed that matches the alternator as closely as possible? (I think mine is a 65Ah one right now) or does it not matter? I mean, can i destroy/wear out the battery if the battery is 65Ah and the alternator is 90Ah?

Also, is there anything else i should swap while at it, or something i should know before performing this?
The only thing i know is important is to disconnect the battery before performing this

Thanks!

Hi
As far as I can see the 70A alternator is for the 4-cylinder engine (1.5, 1.8 ) BA, whereas the 90A alternator is for the 2.0 V6 ZXi.
I suggest you stick with the original size.

Batteries probably have a similar thing, but I'm not sure.

Hi!

It does sound like you might have got water in something and fused it - at least, it's a bit of a coincidence. Although, I don't see how an ordinary wash could have got into the electrics under the bonnet unless the bonnet was open, or you used a jetwash and water was forced in where it shouldn't be.

Check you don't have a fluid leak somewhere in the engine itself that's somehow sprayed or leaked leaked into the electrics. Has the bonnet seal failed and water is getting underneath? Your little screenwash hose and the coolant hoses aren't leaking or spraying anything across the engine?

Before you think of changing the alternator, double check the battery, charge it up out of the car, and make sure it's taking/holding charge properly, and isn't faulty / hasn't been damaged in any way. Check also that your battery cables are OK and the connections are clean and fit the battery posts tightly. Then you can be sure the issue is elsewhere.

Try to find out, too, where the burning smell came from - if you had smoke (and it was definitely smoke, and not steam or water vaporising off a hot surface), can you see if anything actually burned out, is there any melted plastic or rubber? If something is damaged and shorting, and a particular sytem keeps working after the ignition is off, that could also be a battery drain.

If you do determine that it's the alternator, get the part number off it, but I think you will need the chunkier version. The Mazda EPC suggests the V6 alternator part no. is K80118300C, and online that's bringing up equivalent parts at 90 amp. I have a 45ah battery in my V6 and it's doing fine.

A quick time-saver: when you remove the alternator belt, note how many turns (half or quarter) you make on the tensioner screw. Then when you replace the belt, tighten the tensioner back up by exactly that number of turns. It might still need a bit of adjustment as the new belt won't be stretched, but it means you'll have it roughly right and won't have to spend hours trying to get the tension even into the right ballpark. It's quite a fine-tuned thing: I had both belts off on several occasions when replacing the PAS, and just a quarter turn too much or too little produces either a horrible rattle or that awful squeal!

While the alternator belt is off, do a visual on the pulleys, check all the nuts are tight but the small guide pulley is still turning freely. While all that's off, you might as well do a quick visual inspection of the other belts as well, or as much as you can as they're in situ, make sure there are no obvious cracks etc.

S

Maybe the voltage regulator is playing up, much cheaper than replacing the alternator but then again you need to make sure it is the regulator to begin with.
As with ah, it doesn't make any difference what the output is, the electrics will only take what it needs, though of course the higher the ah output of the alternator the more will be available to the electrical system, maybe in Sweden with severe winters you need a higher output from the battery for lights, heated window etc

[url]https://www.2carpros.com/articles/how-to-check-a-car-alternator[/url]

You have destroyed the votage regulator for sure!
When there's voltage that's not regulated to the right amount the electronics start playing arround..
Make sure that you DO NOT drive the car like that because you can realy damage some other electronics in the car aswell.
You could go with only voltage regulator change, but it's tricky thing and not like changin oli(if you know what i mean)
Go to an electician guy who do alternators and starters and get him do the job.
Also the V6 is knowed for the lack of space beneath the hood, so if you love your hands, please, get someone else do the job for you!
If you don't trust me, Ask SerenaJ for the space under the hood.

Edit:
For the Z5 engine(1.5) the alternators are 2 types "PD" and "L & S" types.
If you put PD to non PD car loom you can damage the electronics.
If you put L & S one to non L & S one loom you cannot draw current from it.
So it has to be the right generator.That is if you are changing the whole unit.
Make sure that it is from the exactly identical car/engie/loom!!

I have a pdf file about alternators, but i cannot upload it to the site.
If you want i can send it to you to check it for info..

So i just thought i'd close this post nicely, as the problem have been solved.

It turned out to be the build in Alternator Regulator that was shot.
I ended up replacing the entire thing, as i wanted to swap from the 70Ah alternator to a 90Ah one.

When ordering the parts i considered what i would do. Like i said above, i ended up ordering both alternator and regulator, as i did not want to be in the situation where i replaced the regulator, and it still didn't work, and i would have to order an alternator - with a build in regulator, and have a spare regulator i would probably never end up having any use for.

So for the record: Flashing battery light, dependent on the rpm of the car, faulty gauges/jumping gauges and a battery that drains overnight - most likely an alternator regulator problem, and not the alternator.

I think i would have just been able to replace the regulator, and be done with it, but heck, now i got new everything, and it's a 90Ah one, so it's all good.

Thanks so much for all the feedback, and replies - you guys are the best!

- Jacob