Other than the obvious, what other problems/symptoms can become evident with a weak battery in an '86 Vette? I know I had idle problems with my '99 Durango beater when it had a bad battery. Thanks for any input.

 

It can be difficult sometimes.

What exactly is your concern?

 

Pete,
I'm trying to solve a low idle problem and I'm trying to rule out the basic no-brainers before proceeding to the more difficult fixes (IAC, TPS TB cleaning etc). Also, the battery has been in the car for 4 years and I can't see any green in the window and it usually starts right up. Sometimes sluggish startup for return trip home from work after sitting for 7 or 8 hours. Thanks for any help.

 

Anything voltage related will be affected by a battery that is giving insufficient output. However, if the alternator is performing properly, the voltage to all of your electrical devices will be around the 13.8 volt range give or take .5 volts. Some cars idle too low for the alternator to produce the desired 13.8 volts. this may or may not affect certain circuits. On your critical circuits, you will adjust your idle first and then adjust the sensors and other devices to give the appropriate readings. Don't rely on the window indicator on a battery. Use a voltmeter to get an accurate reading. A load tester, can also give a good indication of the battery condition. If in doubt about a battery, replace it. I found that many times a battery can make the difference.

:yesnod:

 

Thanks Sharky, it's time for a new battery. I guess the old battery owes me nothing after being in for 4 years. I'll post results in a few days after I replace the battery.

 

Delco "eye" is fairly accurate as to the cell it lives in. Black means that cell is discharged to a certain extent, does not mean the battery is bad. What we don't know is if the alternator is able to charge the battery properly or if the battery won't take the charge.

Still, without any voltage readings and given 4 years on the battery, Sharky's is a reasonable guess that the battery is weak. I've gone much longer and shorter as well. If the battery was allowed to go dead once in a while, all the more likely it now won't charge.

Takes a couple of days on a charger to get a battery to a point that you can load test it. That will tell the tale on a maintenance free (can't test every cell with a hydrometer). If you have the time charge up the battery and load test it, if you don't have time replace the battery and see what happens. However it is not unusual to have an alternator failure in short order following a battery failure.

Watch volt guage after new battery, if it goes below 12.5V, this is not good. If it goes below 12V with a new battery the alternator is almost surely shot. Should be above 13V almost all the time with GSP kind of driving and everything on.

Good time to replace the battery cable bolts and clean the connections inside those battery cables when the bolts are out. NAPA in Garwood (South Ave.) has the bolts.

I'm on year 4 on an AC/Delco from R&S on Rt. 22 in Plainfield and it's fine. Best is to buy a fresh battery of any make, go to a store that moves batteries. Best is a guy on Rt. 1 in Elizabeth, but I'm too lazy to go there to get an extra year out of a battery!

 

Thanks Pete, I see you are familiar with my neck of the woods. Why don't you email me and maybe we can get together for a beer or two :cheers:
cgentile@jbhanauer.com