Replaced spark plugs and now dead battery?

2005 v6 replaced spark plugs today. Unhooked the negative terminal while replacing plugs. Got it all buttoned up and battery just clicked at me angrily. Trickle charger did nothing so jump started it. Drove around the block and The gauges faded in and out. Parked it and now dead again

What did I do? Not sure how old the battery is but gave me no symptoms of death til today... Argh

 

Sounds like your alternator is taking a dump

 

Are you sure you disconnected the battery properly? sounds like a cross connection. Check your fuses & get a battery test.

 

Just disconnected the negative side and not the positive. I can check with a multimeter.

What volts should it be at running? Not running? If alt is going will the volt fluctuate when the truck is idling?

 

Should be around 12V not running and near 14V running. The fact that the gauges were fading in and out points to a bad alternator.

 

When my battery died it did so with zero warning, jumped it to make it home, the guages and lights dimmed during the drive, i also thought the alternator, but i swapped in a new battery after checking TW and its been fine for a year

 

Yes, gauges dimming could also just be from the alternator straining to charge the dead battery. If the battery is as old as the truck, its definitely time for a new one

 

no multimeter? you would know right away.

 

Thanks for all the help! I'll check with the multimeter in the morning and report back...

 

Did you check to make sure the connections on both the Pos and Neg are Clean and Tight?

Do that.

Question. Why did you disconnect the battery to change the spark plugs for gods sake? I have to know.

 

Good mechanic ?
It's smart thing to disconnect battery every time there is work on electrical components.

 

A 12 volt batter has 6 cells. Each cell should carry a charge between 2.1 and 2.2 volts. A fully charged battery should have a specific gravity reading of 1.625 and read around 12.7 volts at 100%
at 75% charge 12.4 volts
50% charge 12.2 volts
25% charge 12.0 volts
Discharged battery 11.9 volts

These readings should be checked after the battery has been setting for 30 minutes to an hour after any charge otherwise you will get a false reading showing it charged higher then it really is.

Proper alternator voltage output should read between 13.5 and 14.8 volts. There may be some slight variations ( plus or minus .5 volts) in those readings but that range is an average safe range. Much lower and it will not keep a charge and much higher and possible damage to the battery or to some instruments in the vehicle could occur.

Now about removing the negative connection. Yes that is the one that should always be removed. Electric from the battery travels from neg. to pos. not pos. to neg. so disconnecting the neg. is what needs to happen to keep any short circuit from happening.
Now as to what happened in your case. There are several possibilities. One is that the connection is not tight. Another is the terminal needs cleaning or if this is a pre-molded wire and terminal many times the connection breaks inside where it has been pre-molded and when removed and handled and can cause this kind of thing. That would require a new cable or cutting off the old terminal and replacing it with a bolt on terminal if the cable is long enough.

Also your alternator or battery could have failed at the moment you were doing the work with no fault of your own. It does happen just ask any mechanic who has been blamed for something failing that they never worked on.

Last but not least. It is never wise to use your alternator to charge a dead battery. That requires the alternator to work at its max capacity for too long and can shorten the life of the alternator due to excessive internal heat. When I purchase a new battery I always do a full charge on it before hooking it up to the vehicle to be sure the alternator is not being over worked.

 

haha....i thought that too.

very rarely do i disconnect the battery for anything, defiantly not for a spark plug change.

if i'm jumping someone, i will pull the fuse for the amp

 

Great way to possibly fry something you actually need, like an ECU. Accidents happen, and voltage (like water) will take the path of least resistance.

I don't remember what I was working on when I had my Tundra, but I do know I didn't disconnect the battery. Fried some connection at a junction box that worked my actual headlights. Took a Toyota Master Technician two days to trace and fix.

For one bolt and the cost (free) the question shouldn't be why do it, it's why not do it? Any electrical shit I do now, that battery gets it's negative terminal disconnected.

 

At first I did not disconnect it. Then I had a feeling that I should. Now I see how much good it actually did :/ however who knows the damage I may have caused had I not removed the terminal. DIY is always an experience to say the least. Will check volts and terminals this am!

 

Battery reads 9.6 and not a chance that will start the truck. I'll try a new battery or a charge to start

 

9.6 is a goner. not many trickle chargers will bring one up from that.

i bet a new battery fixes everything, and it was just a strange coincidence. i also disconnect the negative cable when i do my spark plugs. just a habit at this point.

 

yeah i would say the battery is shot ! before you replace the battery i would for sure get the truck running and test the out put of the alt.. that way you don't take the chance of frying the alt and the new battery !

 

Jump started it again and the alt was charging at 13.9 ish. Turned truck off and within two minute the battery reads 7.5 death with no return!

 

Ur gonna kill that alt.