97 1uz into 87 supra wiring help?????

[taka21]

hey everyone im trying to make a patch harness between the 971uz and my 87 supra
i have all the plugs nessesary to make the patch harness but im having trouble finding which wires go where
im using info from several different sources but nobody seems to have any info on this late model engine wiring
if anyone can point me in the right direction it would be greatly appreciated
thank you

 

[taka21]

here is a pic of a patch harness i found

 

[sideshow]

that patch harness is a 1uz from an sc400 to a supra
they r not hard to make just need time n patiance
but that patch hanress is not 100%
i can see its missing the big plug that is on the engine harness on the front left inner gaurd so just proves not many hanresses can be made to plug directly in without making the patch harness bulky
what is the 97 1uz out off
if its a soarer the diags are easy to find u just have to search
then get your multi meter out and start probing

 

[sideshow]

the dash plugs for the sc400s dont chnage much from year to year
so a 97 might be similar to a 94 on the plugs that goto the dash and rest of car

 

[taka21]

ok cool im so glad you commented im really trying to learn how to do this right.
from what im told the 97 wiring is the same as the 96. the 94 is still obd1 if im not mistaken and my 97 is obd2
the issue that im running into is that there are several wires that are simply not in the connectors (and never were on the dash harness i pulled) the engine harness is complete and un cut. i can only assume that the wiring actually changed.
i know you usually charge for sparkie help so i really appreciate all your input and advice on here
thank you

 

[taka21]

the 97 uz is out of a 97 sc400

 

[LT_Chambers]

I have made a patch harnness as well, I used the EWD for a 1994 SC400 and the EWD for the 87 Supra to learn how the two harness should connect. I would suggest picking up at least the SC400 EWD, I found mine on ebay.

When I started I assumed my 1UZ was a pre 95/6 changeover but turns out I have one that has the "newer" harness. I only found a couple of wires that were not the same, so for the vast majority of the wires they were good to go while using the 1994 EWD book. I have just over 4K miles on my set up now, I have had a couple of hickups with wiring, but they were all a easy fix, it just took time to determine the problem.

 

[4U2QUIK]

I have the 94 ewd, I'll repost pics when I have time.

 

[taka21]

awesome thanks

@LT you wouldnt happen to have a pic of that patch harness would you ?

and also im only seeing one place to connect the fuel line to
does the newer motor not have a return line?

 

[sideshow]

i never use patch harnesses
just means u have extra connections and solder joins
just cut of both harnesses and make one out of the 2 and make it plug in
the more connectors or joins u have means extra places for bad connections

 

[LT_Chambers]

i never use patch harnesses
just means u have extra connections and solder joins
just cut of both harnesses and make one out of the 2 and make it plug in
the more connectors or joins u have means extra places for bad connections

Yea, I found a bad connection on my patch harness, the femail "pin" on the ECUs' power supply was slightly bent out of shape and was getting a poor connection. But I beleive the main reason we all make these harness is have a plug and play set up. For me, I wanted to impact the car/enigne in the least way possible so if needed, I could pull the engine out and sell it, since the harness is intact it would be marketable to anyone looking for a 1UZ.

awesome thanks

@LT you wouldnt happen to have a pic of that patch harness would you ?

and also im only seeing one place to connect the fuel line to
does the newer motor not have a return line?

I can, If I get a chance later today I shall!

I have the 94 ewd, I'll repost pics when I have time.

I think it may be time to compile all our findings in a new thread, you seem to have a good understanding of the wiring from the EWD, as do I. If you want to compare notes please PM me, I would like to see a thread dedicated to the 1UZ pinouts/ MA70 pinouts for required plugs. Maybe even some simple schematic wiring diagrams to help clear the smoke.

 

[LT_Chambers]

awesome thanks

@LT you wouldnt happen to have a pic of that patch harness would you ?

and also im only seeing one place to connect the fuel line to
does the newer motor not have a return line?

Ahh, missed the second part, there is a return line, on mine it was behind the driver’s side valve cover (side opposite the throttle body). It is just a metal pipe with a "flared" end that the rubber return line slides over with a hose clamp.

 

[taka21]

anyone who has done this please feel free to chime in
1 how did you run your alternator wiring and is it as simple as it looks?
2 did you have to run all three wires off the eb2 connector through the firewall and connect them to the b1 connector
im using the writeup on 1uzsupras.com and im a lil confused

 

[milisakeracing]

anyone who has done this please feel free to chime in
1 how did you run your alternator wiring and is it as simple as it looks?
2 did you have to run all three wires off the eb2 connector through the firewall and connect them to the b1 connector
im using the writeup on 1uzsupras.com and im a lil confused

1. Alternator wiring is as simple as it looks. Even the color of the wires ended up being the same on my 1UZ harness and my 7M harness. Just had to extend the wires from the 1UZ alt to the battery side. I did this by just using some additional wiring loom and running the wires through the front valence area (in front of the radiator) and snugging the loom up so nothing appears to be out of place or dangling.

2. Only the black and the Orange/black wires are run into the firewall. Sorry for the confusion. Those write-ups really need to be revised with connector designations, pin numbers, etc. One of these days. Like I said in another post where you asked the same question, it's on the todo list and has been there for ~2yr. LT (iirc) sent me some scans of his notes but I haven't had time yet to get them cleaned up and uploaded If someone wants to take on this update, feel free to use all of our notes and put something together, I'll be more than happy to host it just like what I've done with Viper's stuff.

 

[4U2QUIK]

I'm pretty much working on the same thing. I was planning on giving it to you to post up after I was done.

 

[taka21]

I'm pretty much working on the same thing. I was planning on giving it to you to post up after I was done.

cool lol i think we are all on the same page with getting this writeup done accurately lol

 

[taka21]

ok im running into an issue here where im not getting any spark and the injectors are not firing
anyone have any ideas?

 

[4U2QUIK]

sounds like there's no power to those circuits. they're all on the same circut so.....

 

[taka21]

sounds like there's no power to those circuits. they're all on the same circut so.....

is that circut affected by the neutral saftey switch?
and what trans connector is that on so i can jumper it

 

[milisakeracing]

is that circut affected by the neutral saftey switch?
and what trans connector is that on so i can jumper it

I don't recall if it is affected or not. For me, it ended up being grounding issues at the igniters and the ground to the intake manifold.