Try to jump car. Blows 100amp ALT fuse?

[Ihatethisdsm]

ok so i had a bad alternator. so i replaced the alternator had it tested and pulls consistant 14.3v I take the car for a drive and i get back and i park it and let it idle for a minute and the car just dies.

This is a 96 GST bone stock inside and out. so i check the battery and battery level is low. i hook up a battery charger to it. set it on 10amp charge. battery charged up. I go to start it and it doesnt wanna start. I left it alone for that day but battery was good to go had 12.5v on it.

I come back out in the morning to work on it and the battery is dead again!! so i decide to try to charge it again and see if i can find the draw on the battery. i put the negative terminal on. and as soon as i touched the positive terminal it blows the alternator fuse.

Now im just left stumped at this point. i see no breaks in any of the wires.

 

[97dark_angel]

you seem to be crossed some were check by the alternator nuts and make sure that they are not touching metal like the exhaust,

 

[Ihatethisdsm]

ok checked the wires and everything is secured and out of the way. alternator wires are tight. starter cables are tight. battery cables are all tight. all grounds are on the engine as far as i know.

i replaced the alternator fuse. and put it on a low amp charge 2amp. and now the headlights and horn turn on when i hook up the charger.. WTF? im lost for words on this one.

 

[Mr PopUps]

Didnt occur to you that the battery is more than likely dead also??

 

[djordan97]

headlights and horn coming on is the stock alarm activating you'll have to turn the alarm off to get it to stop that.

 

[BogusSVO]

12.5 volts is a weak battery, most all automotive batteries are 2.1v per cell so at a min you have to have 12.6 for a battery to be good.

what voltage drop do you see when you engauge the starter? as a guess i would say it should drop no lower that 10.5v when cranking

but that also depends on cranking compression and how hard the engine is to turn over.

 

[kergilman]

Also the rule of thumb is when you are experiencing a dying alternator and swap it out, you should always charge the battery up seperately before running it on the new alt. as the new alt. can blow out cells of the used battery attempting to charge that depleated battery.

 

[luv2rallye]

Yes test the battery first as it may have a shorted cell:

Charge it up if you can. Then measure battery voltage (should be 12V or higher - normally 12.6V). Now turn high beams on for 30-60 seconds and again measure battery voltage with them on (should be 11.5V or higher and within 0.5V of last measurement or bad battery).

If battery ok you most likely have a short. Do this: http://www.dsmtuners.com/forums/art...-partial-short-battery-drain.html#post1496998

 

[my dreamt dsm]

You might have a short somewhere. Another thing you can try is add a 16 gauge or 14 gauge to the altenator for extra power from a good ground from the body. If it starts and maintains to run, you have a bad ground or bad short. I never found the problem on My civic, but as soon as I take the new alt ground off, my car wont start or maintan a charge.

 

[Ihatethisdsm]

Put a brand new battery in. and has a brand new alternator both have been tested and are in good working order.

I made a new charge harness that goes from the battery to alternator and to stock fuse box. then another power wire down to the starter.

As soon as i put the + terminal on the battery it blows the 100amp fuse and non of the power accessories work. WTF is goin on with this car?

 

[Ihatethisdsm]

OK i did a search for this. and there was no resolution to any of the the threads.

I have put in a new battery and a new alternator. and as soon as i put on the battery cables it blows the fuse right away and i dont know why.

I built a new charge harness for the car. used 4 awg wire with new connectors going from the alternator to the battery. then battery to the fuse box then battery to starter.

ive blown 3 fuses and i am stumped. nothing is touching the power wire. there is no stray wires from the alternator hitting the housing. I have checked and rechecked for a short and i have found nothing on it.

The alternator is a Reman from Mitsubishi since they said they do not make any brand new ones.

 

[Calan]

You still have a short somewhere. Which fuse(s) keeps blowing...just the alternator?

 

[LiquidX]

Are you positive that your larger wire and connectors aren't touching anything else even in fuse box? Put the connectors on the right terminals? Did you clean off the grounds or run new wires for that?

 

[Ihatethisdsm]

yes its just the alternator. no breaks in the insulation. no wires touching anything all power cables were heat shrink and tape incase of a stray wire all connections good in fuse box.

 

[TALONTRAX]

It`s possible that the positive lug on the alternator is shorted to ground internally inside the alternator . . . to confirm/eliminate this, disconnect the battery, then remove the charging wire from the lug on the alternator. Then, re-connect the battery & see if the fuse pops again. If it doesn`t, the alt. is internally shorted to ground & needs to be replaced . . .

Edit -
during this procedure - make sure that the loose charging wire is insulated & not touching anything (grounding out) !

 

[Calan]

I think the key to your problem lies in "I built a new charge harness for the car"

I would get out the voltmeter and check continuity along all the wiring paths you reworked.

 

[Ihatethisdsm]

No the charge harness was built correctly. the old charge harness had several breaks in the insulation and connectors were crappy so i made a new one.

Charge harness is not hard to make at all.