My V6 190000 97 4runners battery died it was 3 years old , I replaced it 2 weeks ago truck ran fine for four days then dead battery again, runs fine if jumped, Returned battery and starts right up , 12 volts on meter at the battery with truck off 14.6 with truck running, Cleaned terminals , ground wire 4inches long from negative terminal to fender looks good , 2nd battery died in 5 days totally dead 0 on meter, Hard to jump , had to ground negative cable on block but runs fine once started. Thanks for any and all help

 

14.6 volts is kind of high for the engine running unless the battery is totally dead and is being charged at max current. Also, you say for the jump start, you need to use the neg. cable/block connection. Sounds like you might have a bad ground connection to the battery. Could be corrosion under the insulation. With engine running, measure voltage drops across the various power and ground cables between the battery and engine. And if that is all OK, might be alternator is over charging the battery and that will kill a new battery pretty fast. And also hook up an ammeter between the battery and pos. or neg. cable with the engine off and see if anything is draining current out of the battery.

 

Just put a 3rd battery in started right up 14.3 on the meter running, battery is fully charged, 14.3 at the ground ,14.4 at the alternator , 14.3 at 5 other locations ,both sides of the 100amp fuse , both terminals. Going to get a dc ammeter to check for a draw with everything off . Cleaned ground connection. Next Step ? Thanks again

 

check for draw is the next step. There has to be a huge drain to kill your battery like that. You should also load test your alternator.

 

You should always have a ground cable to the block, even if you ground to the fender near the battery.

How long does it sit before it goes dead, while your at work, over night???

Sounds like a severe current leak. What is the voltage at the battery 4 or 5 hours after it has sat?

This might sound silly but did you clean up and check your pos. and neg. leads when you changed out the battery? The pos. lead is notorious for going bad near the under hood fuse box if i'm not mistaken. I had to fix mine. I realize you said you cleaned terminals but make sure they are SHINY clean, and do that on both end of each cable.

If you have the standard lead (I think?) battery terminals, is one of them cracked or streched? If so you'll never get enough pressure on the terminal for good current flow. Make certain they are tight, but don't over tighten and break one! Also check your output wire on the alternator for the same problems.

Any one of those things would keep a perfectly good battery from starting your truck and