bmsport

I'm working with the jdm harness for my GTE swap and i would overall recommend to everyone that they only look for a us spec harnesses because the jdm harness is very different and will require alot more work to make it fit.

Using Phil's manual, we mated the 6 IJxx lexus plugs needed to run the car using only the pins numbers provided because the colors are completely different. But from the sources i could find, i had to assume the pins locations were the same. All of the interior plugs went fine except for the lexus starter wire IJ2-8 (black) which was suppost to go to supra IJ1-2 (black). For some reason the jdm harness had no black wire at IJ1-2. Other than that, all the pins were correct (i hope). I apologize for the blurry pics, my cam doesnt like close ups. Pic:



UPDATE: Secondly, all connectors plugged in except ONE of the two medium sized connectors that plug in right below the fuse box. The JDM harness connector on the right in the second picture is completly different than the lexus connector on the left in the first picture. Looks like we'll have to mate the lexus connector off the GE harness to the jdm harness, colors are on the wires are similar.

SC300 PLUGS:


JDM HARNESS PLUGS:


Third, the small 2 wire power steering sensor plug is of course located on the opposite side, so this must be extended to the opposite side to accomodate for LHD.

Fourth. and the worst part, is the jdm harness IS NOT long enough to reach the ecu location via the stock route. I don't know why i didn't realize this before, but its a fact. We aren't about to cut and extend the 100+ wires that need to be lenthened, so looks like the harness will just have to find a shorter route to the ecu. Possibly mount the ecu upside down also. Thats about it for now, looks like we have our work cut out for us.

-Matt

DIrEctQL

Getting a US-spec harness sounds good at this point. Perhaps that would be the easiest way to do.

Chris

bmsport

I'm not 100% sure a us spec harness will fit a jdm engine. Probably most connectors would be same and of course the harness lenth would be better. I'd say start with a us spec clip if possible. I'm not saying a jdm harness doesn't work, it just requires alot of extra attention. I will not be switching to the us spec harness since they run over $1k from toyota.

Tommyd1919

OL NO THE SHEER HORROR OF IT ALL!!!!!!!!!! makes me want to get started putting my swap off till like next year.....ha

DIrEctQL

650 bucks actually. You still have you modify it but then again... no need to extend it and it fits in perfectly.

Say, can I get your help making my harness? What are you doing on halloween? Scarry, isn't?

Chris

bmsport

I'd say your crazy if you don't ask for my help. I've been doing research on this subject on this forum for a while and there are still all these suprises. Don't get me wrong, this forum is helpful and all, but no where near all inclusive. I know others have been through this same situation, but all i could find was theories and opinions. Thats why i'm posting this solid information, so others don't have to make the same mistakes.

DIrEctQL

I don't have the parts yet. When I do I will hit you up.

Anyway, perhaps someone should document this thing. Phil did a great job with the manual but it's not for J-spec.

Chris

bmsport

So what do you guys think, take a chance and extend the harness (90% error margin if i did it), or put a small enough hole right by the heater holes in the upper firewall so the harness will reach the ecu. btw, i measured the hole out and it will reach the 6 connectors on the opposite side. I'm actually leaning toward the second one.

DIrEctQL

I would either buy a one of these harness entenders from mvpmotorsports and extend that. Otherwise extend your current harness. I think it would be much cleaner if everything is like stock... I think I may for with a US-spec Supra TT harness and modify that.

Chris

ACleanSC4

iTrader: (7)

Well I have a Jspec 2jz-gte in my SC300 and I believe when they did the swap, they converted the plugs to the US spec engines...

I also have Phil's manual along with supra manuals to help the shop with the install.

Tony

DIrEctQL

You can't just convert. ECU is on the other side and therefor the harness is too short. Then you have to made the old harness with the new one. It sounds simple but it's not.

Chris

Tommyd1919

When I do the Silvia swap into 240s I extend the harness.... IT IS VERY TIME CONSUMING but not hard at all..... Of course don't cut all the wires at once... If it was me I would extend the harness, take a day and a soldering iron and go to work.... Just my 2 cents