Alternator question Options

[East coaster]

I had the alternator go bad in my 3.6 conversion a few months back and I replaced it with a new/rebuilt unit from Pelican. When it originally went bad I was driving to work and at first my stereo started spazzing out and then powered off and I figured my head unit was having a problem. I left it powered off and kept driving, then a couple more miles down the road it felt like I ran out of gas. Since I was sorta pushing reserve I realy thought I may have run out and I got a friend to bring me some gas, which I added only to realize my bettery was dead when I went to start it.

Bottom line......I got the car home and checked the voltage and as expected my alternator wasn't putting out.

I replaced the alternator and all has been good until today. I was driving to work and my stereo once again spazzed out.....this time I knew the warning signs and I turned around managed to get the car back home in the garage before it crapped out. Once I got home I shut it off and tried to restart it and click, click...nothing!

I'm assuming I've once again lost an alternator! Both times this has happened I was using lights, stereo and fresh air blower. I don't usually use all these at once, is it possible that the combo is taxing my alternator?? It shouldn't be because the 3.6 has (I think?) a 100 amp alt.

Any thoughts??? (IMG:style_emoticons/default/confused24.gif)

[Rand]

I never assume alternator first. What was the voltage at the battery terminals with the car running? How's your wiring? The connections all clean and tight at the battery, voltage regulator, and grounds?

[McMark]

(IMG:style_emoticons/default/agree.gif)

[davep]

You don't say anything about the 'idiot light'. If the alternator is not putting out the light should come on. The light should come on when you begin to start the car, and go out when the engine is running. The light is a critical part of the charging system, and can tell you a lot about how the system is working. Is your alternator properly grounded? You may need to attach a ground to the alternator case and measure the difference voltage between that point and the battery negative post; that difference should be very small, and if not you have a ground issue.

Proper battery voltage, fully charged and engine not running, is about 12.8 volts. Charging voltage is about 14 volts across the battery posts; anything less than 12.8 volts and the battery is being discharged.

[East coaster]

Thanks for the suggestions. I have checked every connection I could think of. All grounds are in place and tight/clean. I've used the car for months in between failures, so it's not a solid problem.

I was one bulb holder short when I did my gauges and do not have an idiot light hooked up for the ALT. I need to get that resolved so I have a better indicator than my stereo cutting out!

When troubleshooting last go 'round I had 12V at the battery (static) and when I started the engine it would drop to 11v at idle and as I rev'd the engine it would drop further, all the way down to 9v. I'm assuming that's the draw of the ignition, etc.. When I replaced the ALT, it would give me 14.4v at idle and rev.

I haven't had a chance to check it out yet, but I'm sure it's going to be the same deal. I'd love to find a bad ground or something.....replacing the ALT is no fun!! Thank God I left an access panel in the firewall!!!!

[davep]

Without the idiot light how the H do you get the alternator to start??
It is the current through the light that provides the initial field to start the alternator. When I said it was a CRITICAL part, I meant just that. Correct part # for the bulb and everything. We'll have to throw you in the brig yet.

[East coaster]

Dave.......ya got me puzzled. Are you realy saying that the idiot light is a critical part of the alternator circuit???? If so, I'd like to understand how it ran for almost a year with no problem and then another 3 months following alt replacement with no trouble. The idiot light has never been installed in the life of this car (as a 3.6).

You're just kidding......right?