gerrb

iTrader: (34)

You are welcome sir ! I will guide you through on how to dissect your SC300 harness and merge what you need into the USDM 6speed harness. Yours is even a lot easier being manual trans compared to the auto trans swap.

I promise you , we will get it done so you won't spend a fortune on that 2jzgte swap harness. A lot of other people here have done it after having helped them.

KahnBB6

iTrader: (5)

Gerrb, that means a lot coming from you!

Starting out with a good harness that's already pretty much what it needs to be makes it a lot less daunting. Whereas before I was seriously looking into getting one built from scratch. Except almost no customer WANTS all the factory wiring when they spend that much on a harness

Next I think I will find a junk SC300 Auto harness just for the body plugs and have that ready to cannibalize for the rewiring.

Thank you again, man! I still have a lot to do for this but it's huge that you've hooked me up. And just this morning I heard back from my importer that the harness part number has been discontinued in Japan. Maybe some US Toyota dealers still have a few left in stock but these are effectively no longer available :/

Not an issue for 95% of the people doing any kind of JZ turbo swap or build though.

CatManD3W

iTrader: (18)

Hey Kahn....this may help you for body plug piece......please keep in mind these was done for Aristo Harness.....but the pin numbers will be the same

If you havent already done so pick yourself up a multimeter.....and check wires from each plug to where they go etc....

I have some additional documents that I have if you need additional help....

BODY PLUG CHART SC300 w/ 58W

IK1 (Orange 23 Pin)
2 AE7 (TE2)
3 AF10 (VF1)
4 AF4 (TE1)
5 Pin 17 of the 40 pin ECU Connector
7 Pin 1 of Noise Filter
8 AF12(Tachometer Output from Igniter) Pin 1 of 4 Pin Igniter Connector
9 AF9 (Engine Coolant Temperature Dash Sensor)
11 (Re-use SC300 Reverse Plug)
20 AF8 (Low Oil Pressure Switch)

IK2 (White 25 Pin)
9 AE2 (Check Engine Light)
10 AD1 (Low Oil Level Switch)
23 Pin 3 of EB1
24 Add to Front Intake Manifold Ground of GTE harness

IJ1 (Grey 14 Pin)
1 AC15 (Fuel Pump Power Supply)
2 Pin 2 of II1 & Pin 2 of Heater Valve Plug
4 Pin 2 of the Horn Plug
5 Pin 2 of the Alternator Connector
7 AF6 (Ignitor Switch Power, Coils, Fuel Injector Input) Pin 2 of 4 Pin Igniter Connector
8 Pin 21 of the 40 pin ECU Connector (Fuel Pump ECU)
9 Pin 1 of the Horn Plug
10 AE14 ( - Ignition Switched Power)
11 (Reuse SC300 Reverse Plug)
12 AE3 ( +B Main EFI Relay)
14 Pin 22 of the 40 pin ECU Connector (Fuel Pump ECU)

II1(White 12 Pin)
1 AC1 (AC -)
4 AC2 (AC +)
1 Pin 7 of the EB1 Connector
2 Pin 2 of the IJ1 Connector & Pin 2 of Heater Valve Plug
4 Pin 2 of the AC Connector
5 Pin 34 of the 40 Pin Connector (AC Request Signal)
7 Pin 1 of the Heater Valve Plug

Short - Not sure which plug this is?
4 AE3 Pin 2 of O2 sensor

EB1 (Black Fuse Plug 8 Pin)
1 AC5 (AC Magnetic Clutch)
2 Pin 23 of the 40 pin ECU Connector (AC Magnetic Clutch)
3 Pin 23 of IK2 & to Pin 2 of the Park / Neutral Switch (& to Pin 8 of IJ2 (Manual Transmission Cars from Factory))
4 Pin 33 of the 40 pin ECU Connector (Battery)
7 AC1 (AC -)
8 Pin 24 of the 40 pin ECU Connector (Main EFI Relay)

Pin 7 of EB1 goes to Pin 1 of the II1 Connector & to Pin 1 of the AC Connecto

EB2 (Black Fuse Plug 3 Pin)
1 AE3 AF1
2 Pin 1 of the Alternator Connector

40 PIN ECU CONNECTOR
6 AE2 (Check Engine Light)
7 AE13 (REverse Light Plug)
19 AE7 (TE2)
20 AF4 (TE1)
31 AE3 (+B Main EFI Relay)

Alternator Connector
1 Pin 2 of the EB2 Connector
2 Pin 5 of the IJ1 Connector
3 Pin 13 of the IJ2 Connector

IJ2 (Grey 17 Pin)
1 Pin 64 of 80 pin ECU Connector (TPS Idle Sensor)
3 Pin 2 of the 40 pin ECU Connector (No.1 Speed Sensor)
4 Pin 11 of the 40 pin ECU Connector (Cruise Control)
6 Pin 1 of PPS Solenoid (PS)
7 Pin 4 of the 40 pin ECU Connector (Stop Light Switch)
8 Pin 3 of EB1 (for manual transmission cars only)
10 Pin 6 of IJ1 (for SC300)
11 Pin 1 of the 40 pin ECU Connector (Ignition Switch)
13 Pin 3 of the Alternator Connector
16 Pin 2 of PPS Solenoid (PS)

SC300 Short Connector (White 6 Pin)
1 Pin 8 of IK1 Connector
2 Pin 20 of IK1
3 Pin 3 of IJ1
4 Pin 1 of EB2
5 Pin 7 of IJ1


Pin 23 of IK2 to Pin 6 of IJ1....You need to do this or car will not start....(neutral/safety switch)

KahnBB6

iTrader: (5)

Thank you CatMan!! I will need this soon when I get into it. I think I have the SC body plug visual diagrams in a PDF'd TSRM file and I'll use that too. Have to check. I'll post them up for comparison within this thread if I find/obtain them. This definitely will help! Thanks!

vigman

Kahn,
The ONLY Oh by the way on an older harness is the connectors get brittle....and if there is any oil soak on the wiring, they get hard.. and FRACKIN TOYOTA is no longer selling connector shells ( unless it's old stock on the shelf ) . We side stepped that with a NEW ( $1400.00 ) harness....If you want to stop by .. I will turn over all my electrical doc's from our build... ( to big to E mail ) .....
Mike
( PS we are still running GREAT )

KahnBB6

iTrader: (5)

Mike-- I've heard this but I wasn't sure since Driftmotion still sells some VSV connectors and there seems to still be a notable market for JZ harness conversions where those connectors can be replaced.

But if you've tried and been told "no more" then consider my eyebrows raised. I'm waiting on Gerrb's harness to show up this afternoon and will begin inspecting all the connectors and see what (if any) replacement plastic I can find. Though he's shown me pictures and has said it's in very excellent condition for its age and that I shouldn't be concerned.

I'm looking at replacement connectors more for a future rainy day when one does break.

I did try a test order of a new USDM 6-speed harness from Japan before purchasing his and availability came back negative. So if there are any brand new full harnesses still available they are all residual stock left in some USA Toyota dealerships.

Glad to hear your SC is tip top! Yes, I'd love to stop by and get those electrical documents from you soon. That would be a huge help combined with Gerrb's harness thread, your project thread and CatMan's body plug pinout above.

There is also Dropbox (2.5GB space is free) if you're familiar. Though I'd love to stop by and see the cars too. This week isn't good for me but after I'm more free. Let me know?

KahnBB6

iTrader: (5)

The stock USDM 6-speed harness arrived this afternoon! HUGE thank you to Gerrb!!

Plugged in are the OBD1 6-speed ECU and igniter. As described, it's in VERY stock shape and there are only a couple of small areas of wiring to repair and only a small few of connectors to replace (if possible, but mostly for future proofing).

I can't dig into it right now but this is very exciting!

gerrb

iTrader: (34)

glad you received it safely .

as Mike had said , you can do it ... and will save you tons by doing your own swap harness.

let me know in whatever way I can be of help

KahnBB6

iTrader: (5)

It arrived safe and sound Thank you Gerry! Seeing it up close for the first time and knowing I don't have to tear apart the whole thing in this case I think so too. I will have some questions for you soon but I think it's best that I get myself oriented with the thread info first by reading and looking directly at the wiring.

One question for now, though: I only need the body plugs with wire leads from any year SC300, correct? I probably don't need an entire SC300 Auto harness? Though I doubt most people sell just the body plugs. This, since I need to leave the stock running engine setup in my car for now.

I did a quick search on Driftmotion to see what connectors and repair wires they have in stock. I'm going to go over the harness in a couple of days and take notes on what looks obvious for repairs... order what connectors I can... and move next into going over your thread and the other notes.

Also, I already have a Greddy boost cut controller (the old SW-20 spec model) but I think I want to leave any add-on modifications like those to a pre-made ECU patch harness.

Getting a bit ahead of myself for today

gerrb

iTrader: (34)

I would suggest do that ... get yourself familiarize with the harness and see what I wrote on that thread. Just like I said, you are not doing the hardest part which is extending tons of wires.

I would suggest get the entire SC300 harness. Take out the wires / plugs you don't need on it ... same thing with that of the 6speed harness, take out the wires / plugs you don't need on it ... THEN merge the two. Getting a stock SC300 harness will save you a lot of trouble in finding out which wires are interconnected from one connector to the other.

IMHO, it is always better and cleaner if all additions / modifications are in a patch harness.

KahnBB6

iTrader: (5)

^^ Yes, that's where I am at for now. I am very slowly looking through your thread a piece at a time.

From the sound of it there's a bit more than just reading pinouts and swapping all the relevant wires into the correct spots on 2-3 SC body plugs. I am not going to tackle the conversion for the moment.

First, initial repairs to stock.

I'm not very inclined to remove any wiring from the GTE harness but if I did then the TRAC connector and associated wires would be all I would remove. I'm keeping everything else. Honestly if I'm doing the harness work I'd be happy to leave that plugged in at the throttle body as long as the ECU doesn't throw a CEL light and not unwrap much of the wiring in the process.

......

So far I did an initial study of the harness yesterday and identified the obvious areas that needed some repair that I knew I could get OEM replacements for. I ordered the following from Driftmotion:

1x 090-II wire w/large seal ordered for one of the coolant temp sender connectors.
1x crank sensor plug ordered — 2x 090-II wires w/large seals ordered to match
x1 coil connectors ordered — x12 090-II wires w/large seals ordered for all the coil connectors
x1 other coolant temp sensor connector — x2 070 terminals w/small wire seals needed

DM's invoice list:
DM1573 Coolant Temp Sensor Connector 2 Pin x1
DM1575 Ignition Coil Connector 2 Pin x1
DM1599-0001 Repair Wire, 090-II Terminal - With Large Seal x15
DM1576 Crank/Cam Sensor Connector 2 Pin x1
DM1612-0002 Repair Wire, 070 Terminal - With Small Seal x2

I'm aware that they have the larger(?) gauge 040 repair wires as well. I'm guessing that those are what are needed to be used at the ECU and body connector areas for any repairs.

Most of the coil connector wires look like the insulation has cracked a bit so I want to redo all of them.

I have to agree that all in all for a 20+ year old harness that saw a lot of turbo heat it indeed is very intact! I've detailed the few issue or concern areas but there isn't much that's not in great shape!

......

And below are some reference pictures for things I could not immediately identify that are going to need repair and for a couple, connector replacement.

Gerrb, my apologies if these were explicitly laid out in your thread pictures already. I took the cellphone pictures you sent me with identifications and have done my best to match your labels with each corresponding section of the harness.

Below:

The first couple of pictures are of two-wire connector that needs to be replaced. Then of a smaller one that seems OK but which I'd like to replace anyway. Finally a third connector in the upper top right of the first image. Those are the couple I couldn't identify yet.

The last couple of pictures are at one of the ECU connectors and one of the MKIV body plugs where splicing has taken place. It looks very straightforward where to repair those back to stock.

The picture of the bulky connector still wrapped in electrical tape is a headscratcher. I think I saw this on an Aristo harness reference image, suggesting it's a Toyota factory quirk but it also seems to be a very odd place to put a big connector. Is this normal or should I also look to restore that to "stock"?

Finally, just curious if that metal spade wire is "factory" looking including that center bolt section. If not I want to repair it too. There is a larger metal space terminal wire on the harness but that looks 100% original.

Thanks again, Gerrb! I'll try to keep my questions simpler from here on out. It's a bit confusing at first and I want to obtain what repair parts I can

gerrb

iTrader: (34)

Craig - no worries, ask whatever you want and I will help in as much as I possibly can. IF I miss answering a question due to the fact at times I maybe in a hurry, just ask it again , I don't mind . There is really not much to take out from the 6speed wiring harness . Only thing you won't be using on that harness is the sub-tps and traction motor since you will be installing a stock USDM 6speed engine. No harm leaving them there.

What I was referring to removing will be the MKIV body plugs and its wires but IF you just prefer to replace the MKIV body plugs and then solder in the SC Body plugs then no wires would be taken out. Take note though , there is slight wiring differences when it comes to those body plugs that is the reason I said another option is take the whole SC harness body plugs with the associated wires and graft them into the 6speed harness wires. It is your choice.

Let me remind you one thing, before replacing or taking out anything , go and immerse yourself into the whole 2jzgte wiring thread so you see the whole picture. Like the two big fuse plugs (found below the front fuse box) for a MKIV has some slight wiring differences for the fuse plugs of the SC.

Once you have a birds eye view of the thread ,you have your 6speed harness and your SC300 harness, you will understand better what I am trying to say about their differences and what needs to be grafted from one and the other.

The green connector with a broken wire will be your coolant sensor , the other singled yellow wire connector will be your gauge temp sender, the black connector above it is a coil connector and the one on the right with 4 wires is the oxygen sensor connector



That would be for your power steering rack


Those are MKIV body plugs you won't need . Once you get your SC300 harness , you will see what I mean. Those wires are going to an SC body plug or be replaced by the SC body plugs and wires from the SC300 harness. Your choice.


In as much as possible , crimping should not be done on an engine harness since they can become loose with vibration and you will be chasing your tail looking for the problem. Always solder and heat shrink .

Looks to me a junction box or short connector plug .. when you open or take out the tape cover and we see where the wires go, we would be able to identify. Many times , they tape a connector or junction that has no further use.

that looks to me that the original ground terminal was bad and they replaced it with that wire and round holed terminal.

KahnBB6

iTrader: (5)

Thank you Gerry!

Honestly I'd prefer to tear into the harness as little as possible since I am not an expert on this and also since my workspace is very limited. I assume what you meant about wiring differences between the SC and MKIV body plugs is that it's not as simple as de-pinning (or cutting and soldering) one and plugging into the other according to what two pinout diagrams say goes where.

and then there is the fuse box connector that you mentioned also has some wiring differences.

Some of the needed replacement connectors and wires came in today. It's not really that many. I only need 1-2 more and I should be set. Though I haven't yet checked the health of all VSV connectors.

Below that bag I pulled out the shrink insulation material I have on hand to measure.

vigman

I agree with GERB... buy a WHOLE engine harness... the extra wire came in handy and a FEW connectors...
OH FYI In the BODY HARNESS by the tranny " hole " ( ours was an AUTO originally ) had the EXTRA female connector we needed to GRAFT into the engine harness for the REAR 02 sensor...

I see you have the IGNITER... but do you have the dropping resistor pack for the Injectors ??
We went with the ( mallory? ) tach interface box..
We NEVER got the factory water temp gauge to work with any accuracy so we went with an after market sender in the upper radiator hose and external water temp gauge ( E bay China FINEST )

Mike

KahnBB6

iTrader: (5)

Mike, I'm sold on an entire harness. I'm attempting to find another 92-94 SC3 Cali-spec harness (5-speed if possible but Auto more than likely).

I think I'm confused on what you said about the rear O2 sensor wire being grafted with your swap.

My Cali car also originally came with the #3 O2 sensor wiring. However I thought all Supra Twin Turbos were wired for 50-State/CA emissions (excepting 1996 6-speeds and all 1998 TT's) which meant the TT harnesses should have the #3 O2 sensor. The USDM TT #2 cat I have has that O2 sensor provision too.

Will I still need to graft the #3 O2 wiring from an SC300 Cali-spec into the TT harness I have? I know you said your new TT 6-speed harness was missing this provision for some reason-- and I believe you, don't get me wrong. But I thought all TT's were basically set up for 50-state emissions whereas it's the NA SC's and MKIV's that were Federal and Cali respectively.

I need to pull out the 6-speed harness again and look it over carefully. I'm sure I saw three O2 sensor connections on there.

I do have the resistor pack I just didn't hook it up in that picture because only the ECU and ignitor were conveniently in the same box. In my crates I should have every USDM electronic part that harness hooks into, minus the coil packs, spark plugs and TT alternator since those last three haven't been purchased yet. I didn't want to dig everything out but everything is tucked away and grouped in carefully labeled bags for each section of the engine.

Hmm. I'll look up this Mallory (or other spelling). I was going to go with the MSD Tach Adapter but maybe yours is better?

The water temp gauge not working for you is something I'm going to look into. If that's a common quirk with the USDM swap I want to find a solution to make the dash gauge work. You're sure it wasn't just the factory SC water temp gauge malfunctioning?