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Discussion Starter #1
My truck, if it sits for a day or two, wont start. I tested both the alt, and the batt, both check out okay. If I jump start it, it stays running, and after a drive into town (20-30 mins) will restart. All day. It only wont start after it sits. I haven't done any electrical things to it for years, and it's worked fine.:confused:
Any suggestions on a potential key off power draw? Thanks, Corey.

ps-stock alt, optima yellow top battery. No real big current suckers("off road lights",winch, big stereo, etc...)
 

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dissconect the battery, measure voltage, connect battery, measure voltage, if there is a drop, hook volt meter between battery and + post and start pulling fuses untill voltage goes back up. that circut is drawing the current, or something like that:D Also, are you sure the battery is good?
 

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The proper way to test for a draw is to set your VOM to amps not volts(since you are checking for current flow). If your VOM doesn't have an amp setting get a test light and connect it between the negative battery post and the negative cable. If the test light illuminates you have a draw. Check the alternator first. Disconnect it and see if the light goes out. If thats ok start pullin fuses untill the light goes out. That will narrow down what circut the draw is on. My .02
 

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Mine's doing something similar, but I think it's the starter. Here's why: After letting it sit a few days or a week, battery voltage will drop to about 10.5 volts. When I try to start it in that state, it'll rarely start. I'll hear a click as I turn the key back from start to on, and that's it.

Once in awhile, though, it'll catch and turn the starter at normal speed. If it were just a weak battery, I'd expect it turn make some consistent attempt to turn the starter, but too slowly to start. That has *never* happened. It either does nothing, or starts normally.

I believe the starter contacts are worn badly enough that they fail to engage the starter unless the battery is fully charged. Take a look at Roger's writeup at http://4crawler.cruiserpages.com/4x4/CheapTricks/Starter.shtml for directions on how to replace them. I'm going to try this before the weather gets good, but if you do it before then, let us know how it goes. Roger, if you're reading this, what do you think?

BTW, I, too, looked for amp draws trying to find the source of the problem. I'm sure I still have some, but the CB was the biggest one I found. It was pulling over 30mA all the time. I wired it to the ignition switch and went from two days to nearly a week before I have to break out the battery charger.

Mark
 

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I'd try what Jon H and Seabass said first. Their reply seems more related to your trouble. One thing I wanted to suggest was maybe check your ground wires. Not just the ground at the battery,all your ground wires. I found that if a rusted or corouded ground connection is somewhere it can make all kinds of funny things happen. Probly not your trouble but you might just have a pourly connected ground wire somewhere on the truck causing a drain from the battery.

Just an idea hope it helps
 

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Thanks Birdman, I forgot to mention checking the grounds. I'm hoping that's where I find the problem, since I don't have to pull the header to fix it. :D

While I do think that most of us with these symptoms have a draw somewhere, I'm not sure that's the root cause of the starting failures. In my case, I replaced my red top, which helped for a awhile. As soon as winter came and I started driving less, though, the problem returned.

Mark
 

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I know in an old '56 chevy 1-ton I drove in high school just the clock on the radio would drain the POS battery I had in a week in the not so cold AZ winters...
 

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If your battery test good with a good amp draw test and hydrometer. Then check voltage draw on your battery as stated before. Connect an ammeter in line and check to see if the amp are over 2-3 .
Most batteries can handle 1-2 amps draw overnite ,most electrical systems don't have that though,most are miliamps.2 amp draw on a 60 amp hr battery gives you 30hrs with 2amps drawing on it if my math is correct...
Or less depending on the battery state...
Clocks,Radio memory,ECU memory, and any other device that has to have a power source for memory need miliamps only.
But if your battery has a bad cell it can drain down over nite or long periods, if you can check the cells with a hydrometer do it, if not the voltage readings and amp draw test will only test it so far. TO be 100 % sure you need to check with hydrometer.
You do have to have 12.2 volts in the battery to test it,charge it if needed,it it doesnt have the 12 volts it aint gonna start the car ,period. The current draw of the starter roughly 150-180- amps will bring the voltage down to 7-8 which wont be enough to run the electronics ,or ignition for that matter if not an efi motor.
With drops in voltage from old wiring and relays and battery cables you could loose a lot of cranking power over time even with a good battery. But if that battery is good ,you have base to start at.
Then check ;)

Like seabass said:
Check curent draw first ,with a amp meter or voltage meter if you dont have a an amp meter , not a test light it isnt accurate enough,if it is above 1-2 amps you have a problem, start pulling fuses to systems inside the cab ,then if it is still there disconnect the alternator as stated before .
It could be something as simple as a out of adjustment brake lite switch , or alt diode bleeding back.
I have seen headlight relays stick as well ,just enough to draw ,but not light the lights...yep seen a lot of wierd shit when it comes to electrical.

Good luck
Gary


:D
 

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i had some discharge yesterday, but i just got a towel and wiped it up....:flipoff2:

that link to rogers page is a goodie mark, i was havin the same prob...

hi corey!! did you sell your camo 4runner?
 

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Mark,said:
Mine's doing something similar, but I think it's the starter. Here's why: After letting it sit a few days or a week, battery voltage will drop to about 10.5 volts. When I try to start it in that state, it'll rarely start. I'll hear a click as I turn the key back from start to on, and that's it.


My reply about battery voltage was in reference to you about your battery haveing only 10.5 after 2 days or so of sitting .That has nothing to do with with starter draw voltage, as roger is refering to while your cranking the engine over ,or trying to and your voltage drops to 9.5 sometimes when cranking under load.
My concern for you was a parasitic draw over time killing your battery ,
Rogers fix has been done since early gm starters and many others with a solenoid that operates like this . We used to rebuild these way back and turn the armatures as well. :eek: But labor costs have put the squish on that ,and that fact the we have mostly parts replacers working as mechanics now adays anyway.

You still have draw problem or bad battery imho...

Glad too hear about that discharge as well Seabass..dont want that leaking on the trails and all.:eek:

Gary
 

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GaryGreco said:
My reply about battery voltage was in reference to you about your battery having only 10.5 after 2 days or so of sitting .That has nothing to do with with starter draw voltage... You still have a draw problem or bad battery imho...
Agreed. I know my CB was one of them, but I suspect I have others that I still need to find and fix. Now that the CB issue is resolved, it takes a week or so to draw down to 10.5v, rather than 2 days. As the guy on 4x4wire mentioned, a new battery improves things for awhile (by not draining so quickly?) but it doesn't last long.

My point, apparently not well stated, is that my worn contacts prevent the starter from engaging, at all, if the battery is not fully charged. Do you agree? It's important because I don't want to mess with the starter if it's not necessary.

Thanks,

Mark
 

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no not really , your need 12 volts to staart with , the draw down of voltage as you engage the starter with a good battery dips to 10- 9.5 sometimes when cranking. IF you start with 10- 10.5 your at 7- 7.5 whe you turn the key on..and that aint gona do squat not matter how good a starter contacts you have..

The more resistance in the circuit the more draw down on voltage to engage relays or the solenoid in the case , but you have to start with 12.26 volts or your asking your starting system to work without enough voltage to its job.

I would do the fuse routine and check for parasitic draws that are piling up enough to draw it down, that old a truck doesnt have enogh electronic crap on it do a lot of draw down . Were talking miliamps here,anything over an amp is going to take that battery down fast...ie dome lite staying on .....;)


Good luck
Gary
 

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Discussion Starter #14
Thanks for all the help!! When I took it to get it smogged last week i asked the mechanic to test the alt+batt.he said they were good from what the ammeter told him( I actually trust this guy.)I will investigate furthur as weather/time permits...

Booger-No I didn't sell it, I had it traded for a nice 65 fj40, but had to back out :( Now atleast I get to deal w/ this little gremlin instead of the new owner, I'm glad he wasn't stuck with it...)

Corey.
 

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fourlofirst said:
.........he said they were good from what the ammeter told him( I actually trust this guy.)..........
to test the battery correctly, you need to fully charge it, then useing a load tester, put a load on it for X amount of time and the tester cvan tell if it is good or goes down to much. the auto parts store can do this LOAD TEST, a tester is bout $50:eek: no way to tell if the battery can handel a load by a amp meter, not acurately.
 

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Discussion Starter #16
SeaBass44 said:


to test the battery correctly, you need to fully charge it, then useing a load tester, put a load on it for X amount of time and the tester cvan tell if it is good or goes down to much. the auto parts store can do this LOAD TEST, a tester is bout $50:eek: no way to tell if the battery can handel a load by a amp meter, not acurately.
ahhh, the battery was charged,he put it on some type of scope, I "assumed" a ammeter, but probly some sort of load test type thing, he knows what he's doing, and said all was good...:confused: still...I'm gonna check connections/grounds, etc. today.Thanks again!:)
Corey
 

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fourlofirst said:
ahhh, the battery was charged,he put it on some type of scope, I "assumed" a ammeter, but probly some sort of load test type thing, he knows what he's doing, and said all was good...:confused: still...I'm gonna check connections/grounds, etc. today.Thanks again!:)
Corey
\

COOL, ya it would be an amp meter and a load for 20-30 seconds, of hundreds of amps to see if the battery doesn't fall below a certain value.
 

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Discussion Starter #18
Well, I pulled fuses till the light went out-AM1 40 A.Then put an ammeter to it -AM1 40 A.So I pulled the plug on the alternator-My current wich was ~950ma for the whole test dropped to about 500ma.So is my alt screwed even thoughits charging the battery when the truck is running?
85 4runner, efi...
 

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Yes it appears there is a bad diode,leaking current back. Diodes are one way switches for current. They are used to turn a/c current into dc current.
I am suprised the checker they used didnt show that , MY AVR meter would show that , but then i paid $600 for it from Matco in 1980 it will pull a 600 amp load if need ,not that anything we drive would pull a 600amp load on a battery...lol

Take off the alt take it into a AutoZone and they can check it on there machine for this,or some other electrical repair place should have a similar off vehicle tester .

Once you get it close to 950 miliamps or 1 amp the draw is significant enough to bring down the battery after a day or two,which in your case would make sense.

Not common for toyota alts to have a diode problem like that ,make be a rebuilt one with some inferior parts though we don't really know at this point.

If no other draws are in the system ,what is the other 500 miliamps from ? OR did i read your post wrong?
Try to find that as well while your at it.

Gary
 

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My point, apparently not well stated, is that my worn contacts prevent the starter from engaging, at all, if the battery is not fully charged. Do you agree? It's important because I don't want to mess with the starter if it's not necessary.
If you plan on replacing the brushes & stuff in that starter, don't wait... I procrastinated on mine until the worn contacts pretty much trashed the rest of the junk in there. It's only like $40 to have the bearings and brushes done if you take it somewhere that knows what the heck to do. I take my electrics to a farm/deisel repair, they know what's up.
 
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