i have a 1991 mazda miata NA and recently the battery has been dead every time i try to go drive. I tried to just start up twice a day to keep it charged, and it got so bad that even that wouldnt work. So i did a a draw test and the multimeter said there was no draw. So i tested the battery at autozone and they said that it was a fine battery. So i decided i would try to disconnect the aftermarket radio, and that didn't work. Any suggestions?
This happened to me and despite all I know about cars in general, I forgot one thing. Check the belts.
Mine had gotten old and glazed, so that it didn't grip the alternator pulley and the car would discharge only at night when the headlights and accessories were on.
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MiataQuest (05-05-2017),NCGreasemonkey (05-04-2017),The Driver (05-04-2017)
@ idle the Battery is doing most of the work. If you are running it to charge the battery during the day run it up to 2000-2500 RPMs for about 5-10 minutes. Then the alternator is the power source. HTH!
Peace!
... Rick
For the thread on Noir click belowOriginally Posted by Hammerhead
http://mazdaroadster.net/showthread....e-light-Slowly
MiataQuest (05-05-2017)
I would perform these actions in sequence to troubleshoot if the problem is your battery, car draw, or charging system...
* Remove the battery from the car.
* Check the electrolyte levels. Top off as required with distilled water.
* Clean the external surfaces of the battery. (dirty surfaces can create a slow draw)
* Buy a "Battery Tender".
* Attach the Battery tender to the removed battery for 24 hours.
* Disconnect the Battery Tender for 2 days.
* Install the battery and see if the car will crank.
* If no, it is the battery.
* If yes, let the car sit for two days with the battery connected.
* Did it crank?
* If no, you will need to troubleshoot the car drawing down the battery.
* If yes, then you need to double check your charging system.
Last edited by MiataQuest; 05-05-2017 at 12:15 PM.
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Question: are you sure your battery/alternator light is working? Have you tried measuring the voltage at the battery poles while the car is running? IIRC, it sure be around 14.4V during that instance. I suspect your alternator.
Sounds like a weak battery to me, but if Autozone didn't try to sell you one, it must be strong as hell. Alternator would be my next guess.
Since you have a multimeter, do what KFJ said, check voltage at idle. I have a digital voltmeter mounted in my car, it's somewhere between 14-14.4v at idle with everything turned off. If the radiator fan is turned on, the voltage gets pulled down a bit.
Update: Yes, I would do what Kung Fu Jesus says first, then perform my troubleshooting sequence.
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