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Hi all,

My battery went flat. Charged it overnight and can start the Brumby now. The alternator light was flickering on and off for a few days at first. Now it wont come on at all even with the ignition on and the car not running.

If I start it and disconnect the neg battery wire it dies right away....

Alternator? Or something worse?

If the light was solid on I would just replace the alternator, but because its not coming on at all I suspect my electrics are shot somewhere.

Its an 84 Brumby

Thoughts?


Thanks.

yep sounds like dead alternator

alex

Could it be the electronics though? Like something in the wiring? Usually when the light stays on its the alternator, but have never seen a dead alternator cause the light not to come on at all.

best bet is to grab a multimemter and see what voltage is coming off the alternator.

otherwise there is a possiblity it could be the wiring, but seems doubtful.

alex

So If I unplug the wires on the alternator (there is two of them in that clip in) and start it, then put a multimeter on each contact point, that will tell me the voltage yeah?

I'd also do a fuse check - both under the dash and the fusable links near the battery, they're in a black box on the brumby's...

I think you'll find that if you disconnect a battery on any petrol engine while its running it will die regardless of the alternators condition. I'm sure this trick only works on diesels as they don't require spark to run the motor. I'd be interested to hear if I'm wrong.

Cheers

Bennie

I don't recommend disconnecting the battery on any EFI engine that is running. Computers hate power spikes.
Modern diesels that use a fuel shutoff soleniod will stop. Older, simpler diesels will keep on going regardless of what you do to the electrics.
Some carby motors that don't have a fuel shutoff solenoid on the carb will run with the battery disconnected, but this can damage the alternator/regulator.

i suspect your Alternator is shot.

replaced the alternator. It still wont run with the battery disconnected. Alternator light still does not come on when the ignition is on without the motor running.

I'm no expert but from my experience all non-efi motors should run on just alternator power provided the alternator is operating correctly.

Also the alternator I installed is the higher amperage model (60 instead of 55). The model is listed in the book. This wont cause issues will it? Both this one and the original have inbuilt regulators.

put a multi meter on it and see what your getting witht he engine running and engine off... dont disconnect anything, just put the negaitve lead on the battery - and the positive on the positive wire comming out of the alternator.

sounds to me like it oculd be a fuseable link or something of the likes, although if it was, normally you wouldnt get power to anything

i'm having the same trouble at the moment.

i just put in a new engine (the one i bought of justin) and my old alterator is suddenly not working. worked just fine on the old engine before the new one went in.

i've checked all the fuses and fusable links, all fine. the other night i left the battery connected and it was dead in the morning. after a day or charge, everything starts, but the voltage isnt going any higher like you'd expect compared to the engine not running and battery only. also, there is no battery light coming on in the dash before start up or after start up (there is a battery light isnt there???)

now i thought it might have been something i did wrong with the wiring when i put the new engine in, but i checked everything and all looks ok, afterall, the engine does run. the only thing i did between swapping the engines was clean the alternator as it was a bit oily.

any thoughts?

If you figure it out be sure to post the results here!

What are the two wires that plug into the alternator for?
The big battery charge wire should be positive current yes?

the big one should be +ve yeah - it connects direct to the battery through the fusable links. i'm getting slightly more voltage from that point (like 0.1v more) compared to direct to the battery when the car is running. i'm about to go back to my car and get the voltages from the plug

Check the battery voltage when the cars not running, then check it while the car is running. It should be around 12.8v with the car running, if its significantly lower than that your alternator is dead.

shouldnt the voltage be higher than 12.8? like atleast 13? my other car runs 13.4 pretty much all the time and never goes below 13.1 (unless i've got my doof doof way too loud)

Yer you should be safe in the low 13volts aswell.

ok, here goes.

nothing connected to the battery = 12.32v
when i connect the battery that drops to 12.18v (and yes, nothing at all is on, other than the v small current taken for the in-dash clock)

then i start the car

at about a 1250rpm idle, the battery eventually climbs up to 12.8v and stays pretty steady. the voltage at the back of the alternator is 12.95, 12.8ish from both of the plug points

then i fix the idle down to 800rpm. battery voltage steadily falls down to 12.35v and keeps doing. 950rpm or so idle and it very very slowly goes up or stays steady at 12.35. at 1000rpm idle, it slowly goes up, but not far.

then i go for a short drive, less than 2km. when i get back the battery is 12.29v and i turn the car off. it barely starts when i try to start it again.

now the funny stuff. when i first turned the car on and reved it a bit, i got error codes 22, 24, 31, 32, 45 and 51. after that short drive, only 45 and 51 remain. i havent checked what those codes mean (i have a 3 plug vaf ea82t), but thought that was strange.

Okay... The two smaller wires coming from the back of the altenator is Battery sensing and light circuit. The light in the dash is used to excite the diodes in your alternator and if it flickered for a while and then cut out, i'd say u have a blown diode or 2. But seeing as tho u replaced it, it may be that a wire in your "light circuit" has been damaged somewhere. If thats the case then your alternator will not charge because it needs that light to start the charging. You notice that your lights on with ignition and then after you've started the car, it stays on for maybe 2 seconds or so? This is because it is exciting it t start charging is your new alternator second hand? if so, then i'd be taking it to an autoelectrician and tell them to check the diodes. Hope this helps
Cheers.

so sounds like my diode is cactus then since i dont have any battery light on the dashboard before i attempt to start the car??? if so, where is the diode located? (pic would be awesome)

That sort of helps! How do I test the 'light circuit'?

What would an auto elec charge to look at it?