OK here goes,
Recently did some work on the car (94coupe) which included the removal of the opti, water pump, plug wires, exhaust manifolds to replace gaskets, repair broken stud on bottom of manifold, and replace air pump valves. Well, after doing this the car developed a bad miss creating a sputtering feeling and a miss when I drive. As if this were not bad enough, I went to the auto part store last night and on the way there the lights in the dash seemed to dim a little, the little green lights on the heater controls became almost invisible, and the digital volt gauge went from 14.1v to 13.9v then to 14.3v .When I went to leave the part store the car barely cranked over and when started volts went to 12.8v pulled the Alternator right there in the parking lot. They tested it and said they got a reading of between 5v and 6v so I put one on order. Put it back in the car and drove home, for most of the ride it read 14.1v sometimes going to 14.3v .Took it to another parts place today and the machine said 14.1v and never budged from this reading. What is going on with my car???? Is their something that I am missng here or what???? Do I buy the $130 alternator or is this something else causing my problems here???? I have no clue but hate to spend money for a part I don't need. Any help with this would be greatly appreciated. Someone please tell me what to dowith this. Can't find a local shop that can get me in for a couple weeks and this is a daily driver. Thank you in advance for all your knowledge. :chevy :seeya

 

If they say the alternator is ok.......i've had the battery internal short cells and destroying itself....there are six chemical cells within the battery to yield 12 volts.....if three are shorted that is the possible 5-6v you mentioned.....I would guess the battery if the alternator tests out.....or maybe bad connections to the battery....i.e...main power leads...good luck

 

The alternator attempts to maintain 14.7 volts across the battery and is also current limited to protect itself. Under current limiting, the output voltage will fall but only during heavy electrical demand. Also, at idle , the alternator cannot deliver full output current and under a heavy electrical load, the voltage will sag but recover to 14 volts when you get underway. Your dim lights and slow cranking could be poor battery cable connections. I would pull the cables (neg first) and clean them and the battery terminals and replace (neg last). Your alternator could be intermittent and you should keep watch for the battery symbol light on the dash which indicates that the alternator is not charging the battery. This is proof that the alternator has stopped working.

 

OK,
Just to rule out some possible things, I recently cleaned the battery terminals before this happened so I don't think it would be that, only the alternator had a possible reading of 5v to 6v on the test machine at the parts store, and the battery has a reading of 12v when disconnected from the car. Hopefully some more advice can be thrown at this one. Of course thanks to all who have and will hopefully respond. :chevy :seeya

 

Just pay attention to the red battery light on the dash. If your alternator is not working, the battery light will illuminate and it will be time to replace the alternator. Also, I would at least check for tight battery terminal bolts. That isn't hard.

 

the next logical step is did you verify EVERY fuse in the engine compartment and passenger compartment, I ask because if it occurred what accessories where running when the problem occurred to help isolate the location? Did you hear the air pump runnin when this occurred if not bad air pump (because it starts almost depending upon the temp immediately after car starts), how about the belt and tensioner are they within limits? Do you have a scan tool to see what the ECM sees for voltage vs. the gauge cluster tellling you what it thinks is there? i.e. bad cluster vs ECM or other way around....Let me know and we'll keep pluggin away.

kitt

 

Got me a scan tool today and will be checking it on Sunday, car was acting really bad before this happened and I never did figure out why, when this happened and I started the car to leave the part store everything acted as usual except for the guage giving a bad reading. The electronic heat controls always seem to turn on when I start the car and it did this at the time, this is the only accessory that seems to turn on right away that I have ever noticed, as I said everything happened as it usually does except it had a hard time turning over and gave a very low volt reading when it started. The belt is brand new and my battery cables were cleaned and tightened within a week or two prior to this happening. Will let you know what I come up with after Sunday using the scan tool. Thank you all for your help. :chevy :seeya

 

Take a 5/16 wrench and tighten your battery terminal bolts. The neg terminal bolt was loose on mine about a week ago.