Battery Drain.

[bloodontheapex]

Okay, so I need some help.  Never had much by way of electrical problems with my cars, so I know next to nothing about troubleshooting this stuff.

 

Today, my car wouldn't start.  I got a jump and got going again.  After the jump, the car was behaving a little strangely.  The volt meter was pegged at 16, the door beep was going super fast, and the idle was shitty.  It died when I got to my girlfriend's school.  I got another jump and went home.

 

At home, I replaced the battery terminals, charged up a much newer battery, threw in that battery, and started it up.  Ran great, volt meter looked good, door beep was the correct speed.  I thought it was fixed.

 

About an hour ago, I went out to get cigarettes.  The car drove fine there.  When I got into the parking lot, it started to die.  I flicked the lights off and was able to keep it going.  I got home by keeping the revs above 1000.  When I was in the parking lot and the car was acting up, it was exhibiting the same problems as earlier today: pegged volt meter, fast door beep, crap idle.

 

So, what this is telling me that something is draining the battery, the alternator is working overtime to compensate (No clue about the door beep).  Whatever it is, it can drain the battery in just a couple miles, even while diving 40 mph.

 

So where do I start?

[I'm BLUE]

clean your alternator connections (dip in vinegar/stainless brush on a drill/replace/etc) and battery related connections.

then have the alternator/battery load tested locally at a local auto-parts slinger for free.. if they offer that ( they do in my area )

 

internal/external regulator is crap ? ( what year ?) ( if external clean the living crap outta those to )

some external regulators are adjustable ( have a metal cover with two small bolts ) .. just like a mechanical points/condensor :) ( idk if you have or not ? )

 

watch this if you ever think you have a battery drain ... better than my typing lol

[72240z]

You know the battery is just to start the car, after that if the alt is up to snuff it doesnt really matter. The volt meter being pegged at 16 would tell me the voltage regulator is shot. That would explain why the beep was fast too. Then its not working at all forcing the car to run off the battery and allowing the car to drain it. The rpms changing output is another sign its shot. 

The alt doesnt work "overtime", a functional voltage regulator should keep it in a 13-15v range regardless of reasonable load, rpm etc...  

Its hard to diagnose via the web but if I had to guess I would say the voltage regulator is shot and kicking on/off randomly causing either the voltage to max out or to not charge at all 

[bloodontheapex]

It's a 79 810.  Where the hell did they put the voltage regulators on these?  It's external, I know that.

[I'm BLUE]

If its like the z cars ... itll be on the passengers side ,,, above the frame rail ,,, forward of the shock tower(toward radiator)

but idk... i've never owned an 810.

 

rockauto.com has closeouts for $15 + shipping.

clean and test first but more than likely itll be replaced.

 

make sure your new battery is not cooked ... doesnt take much.

[bloodontheapex]

If the battery is cooked, then something is cooking it.  Gone through 2 today.

 

I will add to my symptoms:  At idle, the volt meter bounces around close to 16, pegged with the pedal down.

 

Symptomatic of a dying voltage regularator?  Also, my alternator is new.  Is there any way I can test the regulator without a volt meter?  Are there any more common regulators that will work fine in this car (or a 280z, most things seem to be the same)?  I'm imagining this part will have to be ordered, which means waiting, which means missing class, etc.

[ArchetypeDatsun]

Should look something like this.

 

[I'm BLUE]

yes......

 

do you have a repair manual ?

 

did you read our posts ?

I suggested a free alternative (possibly) to have someone/shop/parts store test it

multi-meters are $10.

 

I see 2 different styles of regulators for 79'

are you 100% sure its external ? :confused:

or internal regulated ?

(if its internally regulated and you just replaced the alternator... theres a good chance theres a problem with)

 

A new alternator (remanned) means crap to me... they do crap jobs on them.... its the main reason I bought a 12-ton press.

I take back those many times at LEAST 1 time.

one time 5 times in a row...... until one worked :rofl:

I hate and avoid , but many times its the only real option !

 

yes car repair means sometimes you have to wait.,, like all of us do ;)

or order parts locally.

 

if you were local I would help ya out and probably be a fairly straight forward fix.

 

you can go to oreily's auto parts website to find cross compatibility

[banzai510(hainz)]

didnt by 79 they went IR type alternator????????????If rock auto doesnt sow the can type volt reg you can assume its a IR type.

I would assume the volt reg id inside the alternstor.

 

you can still ck for a drain.

 

I would disconnect the + out put of the alt also if there id a drain.

 

But to my the alt is over chargingn and cooking the battery(maybe acid all over everything also)

 

By 1979 Im not that good on the electronic on those cars as everything is going Fuel Injected by then

[bloodontheapex]

I had it tested at oreilly's.  They told me it was the battery., they were wrong.

[bloodontheapex]

Y'all were right.  Internal regulator. I just ordered a whole new alternator, because they said they could have it here by 3 pm today.

[banzai510(hainz)]

when a batter cooks be sure to re cheack the water level.

[bloodontheapex]

How would I know if it's cooked?  Nothing is coming out of it, it doesn't make any noise, it's just drained.

[datzenmike]

From the sound of it two different batteries gave the same symptoms so for now eliminate the battery. Anything else like the battery cable ends (like the neg ground on the head and the pos on the starter could be loose or corroded), fusible links, wiring or the alternator is suspect.

 

You have a new alternator coming... swap it and go fro there.

[bloodontheapex]

New alternator is in and seems to be holding.  The volt meter is reading a little high (closer to 15 than 14, although all I have to go off of is that it's between 12 and 16.  My eyes aren't doing well today, had stitches taken out), but the needle is steady and isn't pegging every time I rev.  I snapped the head off of one of the rusty old bolts that holds the alt on, but it seems to be ok.

 

I think someone said it here, but yes, my old alt (less than 6 months old) was a reman unit.  This new one is a brnd new hitachi unit, so hopefully I get a little more life out of it.

 

I also forgot to mention that the kid testing my car at O'reilly's siad something about bad diodes in the alt throwing the same code on his machine as a fucked battery.  I will also say that I have no idea what that machine is, if he was correct in what he said, or the symptoms of bad diodes are.

[datzenmike]

Diodes conduct current only in one direction. Presumably if failed they may allow current the other way and allow the battery voltage to leak to ground. Or maybe it just wasn't charging. 14.8 volts is still ok. and besides... just how accurate is a factory gauge anyway. Most are just so you can see if something has changed and is reading differently.

[bloodontheapex]

Diodes conduct current only in one direction. Presumably if failed they may allow current the other way and allow the battery voltage to leak to ground. Or maybe it just wasn't charging. 14.8 volts is still ok. and besides... just how accurate is a factory gauge anyway. Most are just so you can see if something has changed and is reading differently.

 

That's what I was thinking about the accurancy, but I always think that it would be "on it's own scale."  I'm not sure if this makes sense or is correct, but I imagine that although the measuring device may not accurately reflect the true voltage, two sources of imformation would be accurate in relation to each other.

[datzenmike]

Yeah. If factories had really accurate and quick reading gauges like after market ones, owners would constantly be freaking out. Even stopping quickly can slop oil forward and briefly uncover the pickup, the gauge dips and comes up and the owner freaks. The general public are idiots and simply do not need to be burdened with too much info they don't know what to do with.

[banzai510(hainz)]

I believe you have a Hitachi alternator but doesnt mena it was rebuilt by them. Still can fail depending on who rebuilds them. Nissan is far the best rebuilds I have seen.

 

as I said earlier you could have use the drain test(test light) and removed the + out put wire and this would have confered the diaode being shorted to ground. if light went off then it was the alternator you separaterd from the circut.

 

However you car being a 79 it has more electronic and might needed that diaode as a load test. Like in the video.

[bloodontheapex]

I believe you have a Hitachi alternator but doesnt mena it was rebuilt by them. Still can fail depending on who rebuilds them. Nissan is far the best rebuilds I have seen.

 

as I said earlier you could have use the drain test(test light) and removed the + out put wire and this would have confered the diaode being shorted to ground. if light went off then it was the alternator you separaterd from the circut.

 

However you car being a 79 it has more electronic and might needed that diaode as a load test. Like in the video.

 

What I meant was that I don't think this rebuilt alternator was rebuilt to the highest standards of quality control.  It was rebuilt be a company called Sentry Gold.  Never heard of them.  The guy who put it on probably got the cheapest thing he could find.

[bloodontheapex]

This is one of those "You've got to be fucking kidding me" moments.  I'm on the way to school this morning and all the idiot lights come on, the volt meter is on 12, and the engine is idling at 2k.  I drive back home.  The alternator belt has somehow come off it's pulley and is all streched out.  It's also been eaten to shit by the engine.  Ugh.

[banzai510(hainz)]

spin the alternator. maybe the bearing locked up. Or if you have power sterring that bearing is tight causeing the bext to flip off

[bloodontheapex]

spin the alternator. maybe the bearing locked up. Or if you have power sterring that bearing is tight causeing the bext to flip off

 

Alternator spins fine.  the power steering is run by a different belt.  This one runs just from the crank to the water pump to the alt.  I didn't replace the belt when I put the alt on.  I didn't have the old alt off when I bought it, so I wasn't able to get the core and therefore wasn't able to afford a belt.  I think it was just old, the little strip of metal (or whatever) that's on the belt frayed off, and stretched it out.  It's not broken, but reaaally stretched out.

[bloodontheapex]

I can't believe how much shit had to come off that car to get the alt belt in.  Also, I believe that the old belt stretched naturally, as my new belt is much smaller than it even before the failure this morning.  It's been stretching out for a while.  Me taking it off yesterday was probably just the last straw.

[datzenmike]

No belt = no alt charge = choke heater relay is off = choke comes part on and so does the fast idle setting.