Charging system

Yet another charging system thread. I have a 98 xj 4.o on the way home from work the amp gauge dropped to 0 and never came back. Got hone shut off and restarted and amp was back to normal. took 2 10 mile trips no issue. On the way to work this morning 3 miles from house amp gauge again dropped to zero with no other symptons. Got to work shut off and restarted amp gauge never came above 10. Went home after work same thing. Stopped by Discount Auto(parts store) asked to have my chargung sytem checked the guy hooked it up and initially said "the alternator was bad and then I explained to him the intermittemnt amp gauge he said the screen said check wires but the alternator was probably bad" after reading threads on here I was reluctant to plop down $150 for anew alternator just yet. I popped off the + battery cable and the engine didn't die as I would expect with a bad alternator I let it run about 10 to 15 minutes without the cable off and amp gauge never dropped below 11 or 12. Not sold that it is the alternator. I have read about wires breaking down which sounds right in this situation. Has anyone else ever experienced these symptons? I will do voltage tests in the morning it is pouring rain right now so I thought I would ask you all in the meantime. Thanks

First of all, you should remember that this is a voltmeter, not an ammeter. Because of this, it is really really unlikely that the zero reading is an actual reading of your battery condition, or you would be dead in the water. If your alternator failed, your voltage would drop steadily, your lights would dim, and eventually you would stall, all long before the voltage actually reached zero. And of course there's no way you would restart after shutting down.

Check the wiring to your gauge first, and possibly the gauge itself. It might even be worthwhile next time this happens to whack the dasboard with your fist and see if anything happens.

It's not a very good idea to disconnect the battery while the engine is running. It's not good for the electronics in these newfangled gadget-ridden buggies. I know that back in 1959 or some time, Chrysler touted its new alternators by doing that and driving a Valiant across the country, but they had an unlimited source of replacement alternators, and the radio probably ran on tubes.

Sorry to dig up an old thread, but I guess it's better than starting a new one..

I'm having the exact same issues that "The Federation" is having with the exception that my gauge never goes down to zero. Intermittently, when I start the engine, the gauge will read around 9 or 10 and stay there for a while. Then out of no where, it will jump up to 14.

Other times, it will be at 14 when I first start it, and then drop to 9 or 10 again. This is a very intermittent problem that seems to have no rhyme or reason as to why it's happening or how long it will stay low until it finally jumps back to fully charging again.

Is it the wiring? Is it the gauge? Is it the alt? Did anyone find out? Does anyone have any more info about this?

it appears that it was a loose connector on the alternator

CJHVN said:

Sorry to dig up an old thread, but I guess it's better than starting a new one..

I'm having the exact same issues that "The Federation" is having with the exception that my gauge never goes down to zero. Intermittently, when I start the engine, the gauge will read around 9 or 10 and stay there for a while. Then out of no where, it will jump up to 14.

Other times, it will be at 14 when I first start it, and then drop to 9 or 10 again. This is a very intermittent problem that seems to have no rhyme or reason as to why it's happening or how long it will stay low until it finally jumps back to fully charging again.

Is it the wiring? Is it the gauge? Is it the alt? Did anyone find out? Does anyone have any more info about this?

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If this is intermittent, and you have a lot of miles on it, check the brushes on the alternator.