Crazy situation????????

T

TOYOTA 09

New member
So my wife's 2015 4Runner Trail Edition had a dead battery the other day (Date on Battery is 2/2018 (Toyota Factory Battery). So i go out to jump it (Just figuring my son or I didn't shut the door all the way or we a left a light on...do big deal right?) I jump the Runner from my Taco and dive it around a bit. Let it sit for an hour and go back out to try starting it, and it starts like a charm. Fast forward a day or two (Letting it sit without driving it) and I go to start it and its dead. @#%$#%^#$@%@ , so I go to VIP and have them look up what I need, and end up springing for the top of the line AGM battery. Drop it in and go to start the runner and notice its hard to start, but after about 6 seconds it turns over and starts. I think to myself "hmmm that was weird" and proceed to drive the Runner around for 30 minutes. then shut the vehicle off and wait five minutes, and it starts up no problem. I go to bed, wake up this am...go to start it and its dead. Jump it again but this time notice that when driving it around if i depress on the brakes moderately hard my headlights and radio flicker, cut out, then come back on. The engine never stalls out though. Repeat this test multiple times and the headlights and radio are definitely cutting out while braking. I try a nice SLOW brake and the radio and headlights are fine. drive around for 30 mins, pull into my house and turn the runner off, wait 5 seconds and try to start it. I get NOTHING, no lights or radio with the key clicked over just once, won't even click when trying to start it. like the battery is completely dead....

what does the T4R.ORG hive mind think is going on? I did a few google searches which lead me to some sort of Vacuum seal thing?

Any help would be very much obliged !!

Thanks in advance!
 
Register to hide this ad
First thought would be a bad alternator and a new battery that had been sitting and wasn't fully charged so slow cranking. Second thought would be a loose or corroded connection. If alternator test good and starting is hard on a fully charged battery that might indicate indicate a fault on battery side of cables but would still make sense to check alternator connections, engine grounds and all that
 
I think....(best of my recollection, so look further into this) is that the 4runner alternator does not put out enough volts to properly charge an agm....there is some some simple mod you can do to up the voltage of the regulator....and then you will be gtg.
 
Thanks for the response. I made sure that there wasn't any corrosion on the + and - terminals as well as confirmed they were on snug. I will double check that again tomorrow. I will also have the place that sold me the battery test the alternator. any thing else it could be?
 
lewdog998 said:
I think....(best of my recollection, so look further into this) is that the 4runner alternator does not put out enough volts to properly charge an agm....there is some some simple mod you can do to up the voltage of the regulator....and then you will be gtg.
Click to expand...

intersting, as VIPs/Oriely auto part's computer specifically spit out his Battery as one that would work. any more info on the MOD?
 
I would check both ends of both battery ables to see they are tight and not corroded. Also check all connections to the alternator. The best way to check the charging system is to do so with the engine running and increasing the load on the system. There are testers for this that most shops have.
 
flyrv9 said:
I would check both ends of both battery ables to see they are tight and not corroded. Also check all connections to the alternator. The best way to check the charging system is to do so with the engine running and increasing the load on the system. There are testers for this that most shops have.
Click to expand...

Thanks Im familiar with where the Battery cables meet the battery at the battery terminal, where do they go from there and what do they connect to?
 
TOYOTA 09 said:
Thanks Im familiar with where the Battery cables meet the battery at the battery terminal, where do they go from there and what do they connect to?
Click to expand...
Alternator, starter, chassis ground, and engine ground I think. Best to just trace them, been a while since I have
 
jbtvt said:
First thought would be a bad alternator and a new battery that had been sitting and wasn't fully charged so slow cranking. Second thought would be a loose or corroded connection. If alternator test good and starting is hard on a fully charged battery that might indicate indicate a fault on battery side of cables but would still make sense to check alternator connections, engine grounds and all that
Click to expand...
Exactly what this guy said. Check the voltage with a voltmeter. Solid chance it’s not fully charged. I charged up the AGM I just purchased, before swapping out the OEM battery.
 
put in an OEM battery and make sure it's charged. the lights dimming when slowing down is a tell tale sign of a failing alternator

if the OEM battery works fine, it's the AGM, if not it's likely the alternator. unless you were messing with some wiring as opposed to simply swapping batteries I think it's the AGM battery or alternator

I've read a few posts about AGM batteries dying out without being trickle charged
 
Guys thanks so much for all the help. Took the Runner to VIP/O'Reilys tonight. Battery tested "Bad Battery" Alternator also tested "Bad Voltage regulator" Guy there told me that since the alternator had a "bad voltage regulator code" it probably fried a cell in the new AGM battery, makes sense but still doesn't explain why when installing the new AGM it took about 6 seconds for the runner to turn over and actually start. Doesn't taking dropping a fresh battery in take the alternator out of the equation, until you actually start driving?

they quoted me $225 for the alternator and $446 installed. they said they would replace the battery under warranty, even if it was my bad alternator that fried it.

thoughts?
 
TOYOTA 09 said:
Guys thanks so much for all the help. Took the Runner to VIP/O'Reilys tonight. Battery tested "Bad Battery" Alternator also tested "Bad Voltage regulator" Guy there told me that since the alternator had a "bad voltage regulator code" it probably fried a cell in the new AGM battery, makes sense but still doesn't explain why when installing the new AGM it took about 6 seconds for the runner to turn over and actually start. Doesn't taking dropping a fresh battery in take the alternator out of the equation, until you actually start driving?

they quoted me $225 for the alternator and $446 installed. they said they would replace the battery under warranty, even if it was my bad alternator that fried it.

thoughts?
Click to expand...

All makes sense.

As for your first start with your new AGM being slow. I replaced my battery in my 4Runner the other day with an Odyssey AGM and it didn't completely turn over the first time (only turned key for 3sec). Tried again and started up no problem. No issue since that first start up.

My guess is by removing all power replacing the battery it probably caused a delay on its very first initial start up.
 
Did you charge the battery before testing it? Any dead battery will fail a load test. We've had AAA fail a battery and try to sell us a new one, declined and it still drove the car fine until she sold it like a year later. I've lost plenty of alternators and can't remember ever frying a battery because of it. If they're warrantying it then whatever, but still. You should be able to get a Denso off Rockauto for around half that price and although I don't know this engine alternators are never hard. Buy a socket set and you could do it yourself in a couple hours even with no experience. Hell, charge it up and drive down here and you can do it in my driveway for free. Maniac electric also sells regulators for most alternators for around $40
 
Toyota09 -before I threw almost $500 at this problem, I'd want to know for sure what is bad. Charging system components, when they go bad, can take each other out in some cases.

The negative battery cable should go directly to a hard ground. It should be tight and corrosion free at both ends. It should be easy to follow. Same with the positive cable - it should go to the starter. It may go to a starter solenoid first - or that may be at the starter. It should be easy to follow too. It should also be tight and corrosion free. Inspect all wiring to make sure there is no damaged insulation. Also, check all connections to the alternator. Looking up the starting / charging system diagram for your make, model and year of 4Runner would give you the specifics. Might as well look for rodent damage as well.

Most repair shops have a tester that will diagnose charging system problems with the vehicle running and can tell you what is wrong. Part of this testing is to apply a load to the system to check the alternators ability to supply power (part of the alternator's job is to charge the battery via the voltage regulator). Most auto parts stores don't have this equipment. Most can test an alternator or battery if you remove it and take it in; but those tests are limited and leave out the rest of the system.

Since your battery is almost 4 years old - it would be suspect. However, I'd what to know if there are any other issues here. After re-reading your initial post, I'd also check to make sure everything is off when you turn the vehicle off. There is a certain amount of parasitic draw in most vehicle electrical systems. Keeping the radio presets and clock correct are two examples. With several computers in each vehicle - there are more. Most vehicles are designed to handle this for a certain amount of time. However, there could be a problem (such as a door ajar or light left on or ?) that could be a cause as well. Anyway, I'd start with an inspection; followed by good diagnostic testing. Good luck.
 
There is a diode you can install, piggyback, into fuse panel that'll bump the voltage to properly charge an AGM.

I will find a link, but I installed one in my FJ when I installed the Odyssey battery. Bumped the voltage quite a bit.
 
You must log in or register to reply here.

Members online

Total: 352 (members: 4, guests: 348)

Forum statistics

Threads
278,307
Messages
3,554,048
Members
248,016
Latest member
Advally Service

Share this page

Trending content

Back
Top