Battery or alternator?

Jorge022770 · Post by **Jorge022770** » Mon Jan 31, 2005 12:25 pm

Hello my friends!

Yesterday , just like I do every time I want to start my engine , I had to jump start my Roadster due to the fact that my battery has been beyond dead for a while. But this time, I removed the jumper cables after the engine started and the engine died as if the alternator was not generating anything.

I am not sure if I removed the cables too soon (removed them as soon as the engine started) , or if the engine revs were not high enough for the alternator (the revs were at 1250-1500rpm) to take over.....or if it is dead!

Is there a way for me to find out whats the deal without having to remove the alternator? I'm trying to avoid that due to all the other things that will have to be removed to get to the alt.

Thanks guys!

Jorge

Dave · Post by **Dave** » Mon Jan 31, 2005 2:35 pm

How about swapping the battery instead? Take the battery out of the vehicle you used to do the jumpstart and use it to replace your roadster battery. Even if your alternator is dead you can still run off of battery power. Start the car. Now, take a voltage reading with a multimeter across the battery terminals. If you are seeing less than 13 volts, you have a problem with your charging system. Alternator, cables, voltage regulator (if it's an externally regulated alternator), etc.

Jorge022770 · Post by **Jorge022770** » Mon Jan 31, 2005 5:58 pm

Dave:

Thanks man! I will swap the batteries and get a volt meter like you suggest. I'll keep you posted.

Thanks again.

Jorge

oilleak · Post by **oilleak** » Mon Jan 31, 2005 8:21 pm

You may well have killed the alternator if the battery is really dead. It doesn't like trying to charge a dead battery every time it's on. Kind of like carrying a big rock around on your back. After a while, you'll fall over.

Post by **dbrick** » Mon Jan 31, 2005 9:50 pm

And NEVER disconnect the battery with the car running to test the alternator, it will blow the internal parts. Diodes or rectifier, I forgot which, but it's not good.

Sears has a great voltmeter for either $9.99 or $19.99, depending on whats on sale. I use it for my backup at work, 2 years, no problems extensive abuse.

Ldino21 · Post by **Ldino21** » Mon Jan 31, 2005 11:45 pm

Also check the Voltage regulator (big box on passenger side fender well), this happened to me, battery went dead, had to swap battery with friend to get home, put in what I thought was a good used alternator, didn't work, tried another, didn't work, put a brand new alternator in still didn't work.

Another roadster owner said swap out the voltage regulator, it worked like a charm.

If you have a voltmeter thats the best thing, then you can check, ignition, starter, regulator, alternator, battery.

Lou Smaldino
66-1600
67-2000
65-1500

Jorge022770 · Post by **Jorge022770** » Wed Feb 02, 2005 1:45 am

Lou, Dave , and Brian:

Although I hope I didn't kill the alt, I will use all the good advice this weekend............thank you very much for the input! I'll let u know!