Got a problem guys.

Was riding in traffic today. Battery Volts shoot to 8. Crap starts to work slowly (window wipers, radio turns off, climate control gets weak)

But then when im out of traffic volts jump to 12 and everything works normal again. But when im sitting at a standstill for a little bit. Volts go to 8.

Any ideas?

 

alt is probably dieing or the plugs on the back of the alt are loose.

And voltage should be at 14.4 volts, with the minimum really being 13.5 volts. 13.5 volts is what is required to charge the battery.

anything under 12.6 volts, indicates that the car is running on battery power, and the alt is not putting out enough juice to even run the car.

Also the idiot lights should have all lit up as soon as the voltage dropped under 11 volts.

 

Will check for alt issues. The guy said he installed a new alt when I bought the car so it might be some connection issue.

My volts never reached 14 before :[

And when the volt meter shot to 12 and under idiot lights didnt flash. Unless I wasnt paying attention.

 

Your problem has to do with your alternator; mostly likely you need a new one. Like Mark said, though, check your connections to it, first.


While Icemark's numbers that he gives you are nice, it is my experience that FCs are old cars, with inaccurate or miscalibrated stock gauges. My engine rebuilder told me that I should see the same numbers as Mark said. However, mine tends to sit at what looks like 12.5-13 while in gear, sometimes spiking as high as 14, and sometimes falling as low as 10-11 when idling. I believe the gauge is just out of adjustment.

 

Great now the car wont even start. All other stuff works though. Lights and window wipers. If the volts jump when im cruising and everything is working doesnt that mean the alt is working? but the battery isnt charging. So the battery might be bad?

 

Get a voltmeter and do a DC voltage test. That will tell you the answer most likely.

DC Voltage Test:
1. Measure the battery voltage with the car off.
2. Start the car.
3. Measure the battery voltage with the car idling.
4. Is the measurement from step one lower than the measurement in step two? If yes, then your alternator is charging. If no, it is not.

If you don't care to do this yourself most auto parts stores will do this for free as well as a load test.

Check the obvious on your battery too. How are the connections? Clean and snug? Loose plug on the alternator?


Josh

 

The alternator failed BECAUSE the P.O. put in a new one. Happens a lot. Save the warranty information when you get a replacement in case you get a lousy one too. If your alternator is in fact bad, I mean. You might need a new battery too, since that 8V sounds like your alt shorting out your battery. Test both.

 

Hey Ex-Eg-Driver, where in the 209 are you at? Stockton?

 

New alt probably means an Autozone reman. In my experience those fail at least 25% of the time. I went through 2 that failed in under a month on my wife's old car before I got one that lasted. And let me tell you, it is a bitch and a half changing an alt on a Geo Metro. I still have scars from 3 years ago.....

 

You got pretty lucky if a autozone alt only fails on you 25% of the time... 50% of them being crap... is much more normal

 

So buy a oem replacement? I think it is a autozone kind. It has green on it.