94 3.8L Power Problem

I own a 1994 pontiac transport 3.8L V6 loaded minus the power sliding door and i have recently encounted some strange problems and i hope to get any input or suggestions before i take it into a shop to get looked at.

First off i was driving normally when all of a sudden my signals started to progressively get slower and slower which is when i first noticed the problem. Naturally i check the battery gauge and notice it is draining slowly, sooooo home i go.

While driving my headlights shut off, stereo loses power and the gauge almost drops to nothing and check engine light comes on right before i reach my house. The van still runs and i get it parked, none of the electrical features work however. Upon shutting off the van it did not start, just stuttered a little. So i went to bed knowing that at one in the morning there wasn't much i could do.

In the morning my uncle comes over to look at it, hes quite mechanically inclined ... so i go out to show him my dead van. It started no problem, however the battery gauge was about a quarter full, not fully charged by any means. It ran idle for about 10 minutes seemingly fine, the battery gauge did not seem to be charging however and when i turned my heat on to see how it was holding a charge it nearly dropped to nothing. When i turned it off again back up to quarter. So i let it idle a bit, my uncle checked the alternator which he believed seemed to be giving charge and he checked the battery which seemed connected and fine. The power features, although slow, did work and my headlights dimly lit. When we tried to give it gas, however, the van stuttered and after running it for about 20 minutes it finally gave in and ran out of juice completely. It won't start now. :banghead:

What i'm wondering is if it could possibly still be the alternator (against my uncles oh wise judgement) or if it may be a sensor or computer related problem? Any information would be HUGELY appreciated as im trying to stay optomistic :grinyes: :grinyes:

Thanks alot.

MOst obviously the alternator is shot. It happens all the time. THe voltage indicator does not tell condition of battery: it tells the voltage at which the system operates, normally , bit over 14V when alternator charges normally.
WHen alternator does not charge, only the battery is left and voltage goes below 12V, and the more loads you turn ON, the less the voltage. The low voltage cannot maintain several of the relays that activate a lot of components, so they turn off one after the other.
Boost the car with another battery to start it,,then measure voltage with a voltmeter: in fact, it will just confirm what you have already told, using the car voltmeter, it will be low. I'd install a new alternator without much hesitation. Mine has done it twice: once the diode pack was shot, the other time, the (built in) voltage regulator was shot. IN both cases, I replaced only the faulty component, about $30 each time: requires some electrical and soldering skill. It is one or the other; possible also, but less probable, the carbon brushes...but they outlast diodes and regulator.

excellent as this is what i thought too and i went and pulled the alternator out of my old trans sport haha. Will install tommorow when daylight permits. Hoped it wasn't anything more serious.

Thanks.