Charging issue

[HUENEMEGN]

So I been having low voltage reading from time to time.. The low voltage light will come on and volts will be from 10-11 on scanmaster on morning start up ,then I will will take a 35 minute ride to work and the low volts light will come off When I get there . This happen about 4 times in a 8 month period. Now car won't start.i jumped start the car and it starts right up . But volts are at 11 then drop to 9-10 car on ! I turn off car then try to restart and it won't . I checked the volt at battery and the alternator and they are both at 11.3 with Car off ! I have yellow top optima maybe a little over a year old and 3+ year old alternator/100 or 120 amp I think ?? What can It be???

 

[we4Mateo]

Your alternator runs the car when it's running so if voltage is low, your alternator either isn't getting energized to charge or it's bad all together.

 

[mikestertwo]

If the idiot light comes on I would say the alternator is bad.

 

[highboostgn]

I had the same problem on my 86. Just replaced the alternator and I was good to go.

 

[whitehot1]

Most of the auto parts stores will test your charging system for you free. If you don't want to drive the car there you could take the alternator off and take it to them and have them just test it for you.

 

[Chuck Leeper]

Run voltage drop tests on the entire system...+ and - sides.[Includes body, chassis grounds]. Check ohm readings across all connections. Clean and inspect all connections. Look at the + cable at the ends for green grunge under the insulation.
And, as mentioned, get the batt and alt tested.

 

[turbo nasty]

I had a similar problem on my old 86 and it was the power wire that feeds the alt off the starter...the previous owner had put another crimp ring terminal on but did a crap job and it was loose and making contact sometimes. Replaced connector and walla

 

[mikestertwo]

I had a similar problem on my old 86 and it was the power wire that feeds the alt off the starter...the previous owner had put another crimp ring terminal on but did a crap job and it was loose and making contact sometimes. Replaced connector and walla

Our cars don't have that wire. There is just the one wire that goes to the idiot light. If the idiot light operates then the alternator should work. I did put an alternator on my car that uses the wire going down to the battery cable. This eliminates the issue with the alternator not charging because of a connection issue to the light in the dash or a burned out idiot light.

 

[turbo nasty]

Our cars DO have a power wire going to the alternator as well as the feild wire going to the dash/volt light (2 wires one is sense...dash.. and one is output...to starter or battery if changed from oem wiring setup).

If the alternator isnt able to exceed/charge batteries reserve/voltage (cant charge with loose or open connection at starter like the scenario I mentioned) then the light is going to light in dash as designed because the sensing wire is sensing low voltage (battery by itself cant handle everything and isnt getting charge from alternator and the voltage is dropping).

Just because the light comes on at key on no start doesnt mean that alternator is bad.....but doesnt mean the wiring is good either. Both wiring and components must be checked.

 

[mikestertwo]

I wasn't talking about a power feed wire to the battery. I was talking about a power sense line from the battery. Most GM cars have a sense line that goes down to the battey cable on the starter solenoid. Ours does not. The only sense line on our cars is the one going to the idiot light.

 

[HUENEMEGN]

Ok... Thanks guys . I guess I check out the alternator and replace it.
What's a good one? I read we can use SS impala alternators . I think they are 140 amp. And is it the 1996 year that I use!
I seen the 240 amp ones but they cost a couple hundreds dollars . Ill have to think about it or just buy it and be done with !

 

[Red C5]

Same symptoms my truck had. Turned out the regulator was bad in the alternator.

 

[HUENEMEGN]

So can I use impala SS alternators and what year is best ?? Thanks guys

 

[JYLP]

So can I use impala SS alternators and what year is best ?? Thanks guys

Yes, I've had one of them on mine before, but it went out in 2 or 3 days and when I took it off, the back cap fell out, so at that point I was pretty sure it was a bad alternator. I would like to know what keeps killing my alternators... think maybe the belt could be too tight and wearing out the bearings? It seems to only do it under load though... I do have a volt booster and hot wire kit. At about 900 rpm it was putting out 13-14 volts, is that normal? I had a stock 120 amp alternator rebuilt to 140-150 amp and it just went out also. When mine go out, they smell normal and there isn't any shaft play. I think I'll have it tested just to make sure it's bad before I take it back to the guy that rebuilt it tomorrow. If anyone has any idea as to why my car keeps killing alternators, let me know.

 

[Chuck Leeper]

Yes, I've had one of them on mine before, but it went out in 2 or 3 days and when I took it off, the back cap fell out, so at that point I was pretty sure it was a bad alternator. I would like to know what keeps killing my alternators... think maybe the belt could be too tight and wearing out the bearings? It seems to only do it under load though... I do have a volt booster and hot wire kit. At about 900 rpm it was putting out 13-14 volts, is that normal? I had a stock 120 amp alternator rebuilt to 140-150 amp and it just went out also. When mine go out, they smell normal and there isn't any shaft play. I think I'll have it tested just to make sure it's bad before I take it back to the guy that rebuilt it tomorrow. If anyone has any idea as to why my car keeps killing alternators, let me know.

I suggest you start your own thread.
As for the belt being too tight....Not if you have the stock tensioner on it. As mentioned above, do the testing and see what you find....