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2016 Toyota Tacoma
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26 Posts
Discussion Starter #1
Ok so im helping a friend with his 98 OB he put in a new used motor and trans and after two weeks the main fuse blew along with most of the other fuses. What could cause this? How can I tell if the computer is still good with out risking damage?
 

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2016 Toyota Tacoma
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Discussion Starter #2
ok I got some more info on the car. Ok he got the engine shipped from japan with ruffly 49k miles on it. Put it in and it drove for a few weeks. one day he heard the battery sizzling so he decided to get a new battery(first warning). about a week after that he was driving home and "POP" when the fuseable link along with eight other fuses. He reconected the fuseable link and got the car to crankover but not start(duh you didnt replace the other fuses). I really think this is has something to do with the alternator. Im gussing a internal short in the alternator could cause something like this? He dosnt want to mess with it and is going to sell it. Is this car worth 1,500 as is?
 

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2010 Subaru Outback 2.5i Premium 6MT
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There are, literally, countless things that could be going on with a full engine/trans swap. Connections could've been hooked up wrong anywhere along the line. Wires could be crossed. Grounds could be incorrect. Your ideas could be correct with the alternator as well, but that sounds pretty **** serious to be caused by a bad alternator.

Do you have more info? What was it like before the swap?
 

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2010 Subaru Outback 2.5i Premium 6MT
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Oh and was the battery sizzling while the car was stopped? There's a major short(s) somewhere.
 

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2016 Toyota Tacoma
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Discussion Starter #5
Oh and was the battery sizzling while the car was stopped? There's a major short(s) somewhere.
yeah he just got out of his car one day and heard it sizziling. I'm thinking about buying it from him. I'm leaning towards a dead short in the alterator. If im lucky I might just drop in an alternator some new fuses and be good to go, and have my first subaru.:D I'm so excited:20:
 

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96 Legacy OBW, EJ22 swap, 2" suspension lift, 215/75r15, HIDs, 06 WRX interior swap
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335 Posts
Our alternators are internally regulated as with all modern cars. When the regulator goes bad it can spike to 18v which is what an alternator is capable of. Causing batt to overcharge/sizzle. Simple alt replacement takes care of that.
 

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2016 Toyota Tacoma
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Discussion Starter #8
There are, literally, countless things that could be going on with a full engine/trans swap. Connections could've been hooked up wrong anywhere along the line. Wires could be crossed. Grounds could be incorrect. Your ideas could be correct with the alternator as well, but that sounds pretty **** serious to be caused by a bad alternator.

Do you have more info? What was it like before the swap?
He put the new motor in because he had overheated it and destroyed the heads. He is a mechanic so I would assume he got everything hooked up right. My theory with the alternator is that it started overcharging the first warning sign of this was the sizziling battery. Then I think it started to overheat and possibly melted some of the insulation in the alternator causing the dead short. It happend to him while he was on the highway.

Im going to try to test my alternator theory by disconecting the alternator, replacing the fusible link and various fuses, and attempting to start the car if it starts I got really lucky and will have my self a subaru if it dosent well at least I tried.
 

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2016 Toyota Tacoma
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Discussion Starter #9
Well I took a good look at it today. We got it turning over but there is no spark. I found out when he put the new battery in the alarm system went off and he decided to cut the wire to the siren. so this live wire was just floating around in shorting out on everything. He didnt have the keyless entry remote anymore so he wasnt able to disable the alarm but he did find the reset switch and try to reset it but I dont know if it worked. It isnt blowing fuses anymore but i wonder if the coil got shorted out(if thats even possible) or maybe the alarm system is somehow keeping power from reaching the coil.
 

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2016 Toyota Tacoma
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Discussion Starter #10
Well I took a good look at it today. We got it turning over but there is no spark. I found out when he put the new battery in the alarm system went off and he decided to cut the wire to the siren. so this live wire was just floating around in shorting out on everything. He didnt have the keyless entry remote anymore so he wasnt able to disable the alarm but he did find the reset switch and try to reset it but I dont know if it worked. It isnt blowing fuses anymore but i wonder if the coil got shorted out(if thats even possible) or maybe the alarm system is somehow keeping power from reaching the coil.
Ok Is it possible the Ignition Control Module Is Bad? I mean its right there next to where the alarms siren wire was floating around if it hit something near it maybe it shorted it out.
 

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Discussion Starter #12
Ok its time to get down to buisness. I want to know do you think this OB is worth buying even with the problems it has? How much would you pay for this as is? And What are some reasons not to buy this OB?

-Thanks
These forums are pretty awesome and I love how active they are :D
 

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Going back a bit, the fact that several fuses blew could take the blame off the alternator. A better idea might be had if we knew exactly which fuses blew (each time, if it happened more than once).

Attached is a wiring diagram that should correspond to the car's system. If the alternator were to short (the "W" wire to ground), then the main fuse between the alternator and the battery (FL 1.25), would take the full current.

However, at the same time, the other fuses (SBFs) would not be handling unusual current as the alternator is not downstream of them, so they shouldn't blow.

If high amperage SBF fuses blew as well, then there must have been a short, or shorts, downstream of those fuses. None of the SBFs is rated as high as the FL 1.25, so a short in a circuit downsteam of a single SBF should not have caused the main fuse to blow (although that one SBF might), but if there were shorts downstream of several SBFs, then it's possible that both those SBFs and the main fuse would blow.

From the diagram, there's three SBFs downstream of FL 1.25; SBF-3, SBF-6 and SBF-7. Were these blown? Any others?

(Sure a screwdriver or wrench wasn't left sitting across some wires?)
 

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2016 Toyota Tacoma
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Discussion Starter #14
:D
Going back a bit, the fact that several fuses blew could take the blame off the alternator. A better idea might be had if we knew exactly which fuses blew (each time, if it happened more than once).

Attached is a wiring diagram that should correspond to the car's system. If the alternator were to short (the "W" wire to ground), then the main fuse between the alternator and the battery (FL 1.25), would take the full current.

However, at the same time, the other fuses (SBFs) would not be handling unusual current as the alternator is not downstream of them, so they shouldn't blow.

If high amperage SBF fuses blew as well, then there must have been a short, or shorts, downstream of those fuses. None of the SBFs is rated as high as the FL 1.25, so a short in a circuit downsteam of a single SBF should not have caused the main fuse to blow (although that one SBF might), but if there were shorts downstream of several SBFs, then it's possible that both those SBFs and the main fuse would blow.

From the diagram, there's three SBFs downstream of FL 1.25; SBF-3, SBF-6 and SBF-7. Were these blown? Any others?

(Sure a screwdriver or wrench wasn't left sitting across some wires?)
Well It's sad to say this but he has decided to part the car out. I have decided not to buy as well. We determined alot today. Bad coil, bad ICM, bad alternator, damaged computer, and other damaged sensors. If anyone wants parts off this it should be on ebay or craigslist sometime.

-Thanks everyone for all the input. Its appreciated. In the meantime my search again begins for a subaru Outback :D
 

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2010 Subaru Outback 2.5i Premium 6MT
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Want to buy a 1998 with 100K on it that needs the HG's and other engine maintenance issues done? ;)

Glad you decided against this one. It seemed like quite the problem. Personally, I hate dealing with electrical issues like that. Once you get one fixed, there's always another mocking you somewhere.
 
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