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Mason

Discharge light + blowing engine fuse

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Heyo, I have a '78 ke36 that gave me the battery discharge light a couple of weeks ago. I noticed it had blown the engine fuse as well. Battery was reading 12.~ volts but wasn't getting charge when the car was running. The old man and I ran some wiring continuity and what we checked around the alternator seemed fine. We did deduce however that the engine fuse stopped blowing when the alternator itself wasn't plugged in, could be its just completing the circuit though. When we plugged the alt back in with an engine fuse in the box and cranked the car it made an ugly sound from the alt then blew the fuse again. So we decided it was probably a dead short in the alt, I put a new alt in last night and got a jump start, bummer, discharge light still there, blew another engine fuse as well. The discharge light did go away for a few minutes which was weird but then came back. So I am at a bit of a loss with this one. Yet to pull wiring apart and have a search but just wondering if anyone has had any similar experiences and would be open to shedding some light. Also please note I am an wiring noob...Thanks :) Mason. 

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Hi Mason,

                  Is the alternator causing all your woes original ?   Does it have an external regulator up on the firewall somewhere, or is it an alternator, with a built in electronic regulator ?

You seem to indicate that the car was running with a "blown" engine fuse, which seems a bit odd, as usually the engine fuse powers the ignition coil ?

Does the car wiring give any indication, it might have been hacked, or changed at any time in it's life ?

Cheers Banjo

Edited by Banjo

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Hey, 

Replaced the old alternator with a new one, didn't solve my charging/blowing fuse issue.
Found a bad wire on the external voltage regulator and soldered that back together. That seems to have fixed my problem.
No more charge light and no more blown fuses, and the battery is charging, however, now I'm getting pulsing lights all throughout the car and my charge voltage is jumping from 13-15 randomly (also affects idle?) So I am thinking the reg is bad. 

Thanks,

Car also did run fine without the engine fuse - just no charge
Also car wiring has definitely been hacked into in its lifetime - unfortunately...

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Hi Mason,

                  From one woe to another, it seems !   As the replacement alternator you obtained was a "new" one, & it is not charging properly, your best option, is to now change the external regulator, if you can get hold of one.  I would suggest to any one who is going to fork out for a new alternator, that they upgrade it to one with more output, & that has an inbuilt solid state regulator.   The original Corolla factory alternators all had outputs of 30-35-or 40 amperes.  Current alternators with 85A output are of similar size, & you'll always have nice bright headlight, instead of the "yellow candles".

Although there are plenty of 85A & upwards alternators available, mounting them is the big issue, & lining up the pulley that the front, with the existing water pump, & crankshaft pulleys.

I used an 85A one out of a earlier model Toyota Hilux, years ago, & it has be fantastic.  It wasn't even new; it was a rebuilt unit. 

I only recently had to replace the regulator, which started to play up. The reason the Hilux alternator was a good substitute, was that it fitted on the existing K Series engine alternator mounting bracket, & only needed about 3 washers to move it, forward, so the pulleys lined up. I think I even transposed the original alternator pulley.

Hope that is another option for you.

Cheers Banjo

 

Edited by Banjo

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Hey! Just following up on this one again, after all the headaches it was the external voltage regulator. So problem solved. One day it would be good to upgrade the alt but as I had already purchased one I guess for now it will stay how it is. 

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Hi Mason,

                   Glad you got it all fixed,  & that we were able to help.  Where are you located ?   Keep an eye out for a good second hand, or rebuilt 85A Hilux alternator with built-in  solid state regulator.  They come up on ebay every now & then.  One of the best upgrades you can do early Rollas.  Pity your cars electrical wiring, has been hacked by someone else previously. Makes it a bit hard for you.

Another thing you can easily do, is clean all the earth points.  Battery negative terminal.  Earth terminal between battery negative & the chassis.  Earth/chassis strap or cable between chassis  & engine block.  That one is very important, as it takes all the starter current, which is the largest load in any car, & potential for the greatest voltage drop or reduction.

Any other electrical issues, just give us a yell.  There are a couple of "experts" on here.  Don't really like using that word "expert".  Ex is a has-been, & a 'spurt", is a drip under pressure !

Cheers  Banjo

                    

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