Yeah, so I've been doing research left and right trying to prepare to do a Turbo II swap, and I keep getting different answers from everyone... can someone that has done this exact swap please just make the wiring harness issue clear to me? Here is an example of more advice I've got for the swap and confused me even more. And NO, I will not have the N/A harness to use for my swap, so I have to make the Jspec harness work. Thanks

My AIM: rottary89

> I am doing a 89 GTU to a 90 JDM Turbo II swap. Using the N374 ECU, JDM
> wiring harness, and N370 boost pressure sensor. I know you recommend using
> the US wiring harness, but if you had to make the Jspec one work, do you
> know how I might go arround doing that?

--you can't...unless you are willing to sacrifice some streetcar necessary
functions such as wipers, cruise, dash temp gauge, a/c and heater blower
motor, etc. These wires/plug are not present in the jspec harness.



I know the harness wont reach
> because of the right hand drive situation, but what if I splice the whole
> harness at the point where it enters the firewall?

--do you have any idea how many wires are in that harness? At least 50.
You'll also make it IMPOSSIBLE to troubleshoot, should you have running
problems or sensor codes later on.



Everything should reach.
> Are there specific connectors different from the Jspec to the US harness?
or
> are there different connectors from the N/A chassis harness to the T2
> harness? Also do I have to worry about the X16 plug by any chance?

--here is an illustration. This writeup is talking about difference between
years of US harness. However you can see that the US harnesses all have 2
plugs for the ecu and 2 more that plug into the dash harness...the JDm
harnesses are all missing one of those 2 big orange junction plugs for the
dash harness altogether. We're talking like 15-20 wires.

http://www.rotaryresurrection.com/2n..._s5_diffs.html

 

I don't know about the JSPEC harness but seems to me you could find a used U.S. harness. Even a N/A one if worse comes to worse. Also do you know for sure if you haven't already gotten the engine/harness that it has the plugs on it? From what I understand many times the wires are cut where they enter the firewall. Not an Rx-7 but on the engine my Brother-in-law got for his Paseo the harness was cut along with anything ellse that hindered removal (hoses,etc). If the harness is cut you'll have to source plugs from a domestic Rx-7 anyway might as well get the whole harness. I know this doesn't answear your original question but it may be some additional items that may hold you up. You could get a front clip. Then you'll have all the JSPEC wiring for the front of the car.

 

Found this on Ebay.

http://cgi.ebay.com/ebaymotors/Mazda...QQcmdZViewItem
http://cgi.ebay.com/ebaymotors/engin...QQcmdZViewItem

They are N/A but should be easier to make work than a Jspec harness. I can't confirm it but I have heard the only difference is you have to add a wire for the knock sensor.

 

First off.. god bless anyone that did what this mans trying to do .. my t2 to a jspec t2 keeping the original harness that was on my car was a night mare all in itself...

Second off.. you better tell the dudes your dealing with that are shipping you this engine that you dont want anything cut short you want a full jpsec harness with everything its connected too.. and honestly they are gonna want to send you a whole front clip and im sure you dont want all that..

Another possibility.. grab this harness for 90 bucks off ebay and avoid all that electrical night mare.. you may have to use some of your old harness' and splice in connectors to it ...

http://cgi.ebay.com/ebaymotors/Mazda...QQcmdZViewItem

And make sure!!! that ur transmission wires match up before you out your tranny in because I didnt do that and I dumped the engine and the tranny all in at once and I still dont have reverse lights and 5th gear light working properly..

And also if another problem I ran into were my injectors and the resistance going to them and I was flooding my engine killing my battery it was a night mare..

I learned alot though not gonna lie it was a good learning experience.. originally I was gonna rebuild but everything was messed up..

That upper intake manifold is gonna hate you too haha get ready to take that thing off and on a million times over hah..

Hopefully you wont run into these problems but I definately did.

good luck

 

longisland87rx7 that harness is for a Series 4. He will need one from a Series 5 or 89-91 car. The harnesses are different. The S4 harness won't plug into the S5 ECU. He also said he won't have the old harness so he won't have the plugs to splice into it.

 

use the stock wiring harness, it is the easiest way.\

it can be done with the jspec harness. drop the engine in and find out.

 

Dak I totally over looked the S5 part.. thats a good link too forgot about that..

 

I am doing this swap... well, S4 TII J-spec engine into S4 GXL. I didn't know that this would be such a problem. I haven't messed with the engine or ECU lately. Haven't had the time. So, we'll run into problems with lights and other sort of things? These harnesses are that different?? Hmm... I'll research this a bit more.

 

well I think I'm going to try the N/A harness instead of the JDM T2 one. So do I have to worry about anything else but they knock sensor? Or are there more things that somehow I've omitted? Thanks for advice everyone

 

Hey I am practically done with my TII swap into my 86rx7. I'm using the N/A harness on a JDM engine. I'm not completely done with wiring it up yet but I'll be sure to tell you how it turns out... all I have to do is connect the wiring harness and I'll be done...

 

cool, good luck man. and let me know what you had to do to make it work and such. Btw, you doing JDM S4 T2 in S4 n/a right?

 

why not just use a US Turbo II wiring harness, itl save you all the hassle.

 

yeah i know, the problem is I can not afford a S5 T2 harness right now, and they are very hard to find as well.

 

I'm not sure I had read that on here somewhere. Here are some links I found in a search.
https://www.rx7club.com/forum/showth...rness+TII+swap
https://www.rx7club.com/forum/showth...I+swap+harness
I'll try to take a look in my FSM in the next day or two and see what the differences are in the wiring diagrams it contains. I need to find out the answear to this anyway since if I ever do the swap I was planning on using my N/A harness as well.

 

Just stand-alone EMS the bitch.
Screw messing with a ~20 year old electrical wiring harness.


-Ted

 

2RotorSpeed... tell me how the N/A harness works out for you. I may just go that route too. If it's somewhat easier.

 

LoL Dont worry, Ill make a thread of how my whole swap went, and exactly what problems I had and how I solved them... when my car will run after swap.

And for those who keep giving me alternatives, thanks, but I've already known about using T2 US harness, or going stand alone, sure they are much better then what I am trying to do, buy the alos require alot more money. My budget is about ~$0, since I still have to buy few things for this swap, and I have to get it done by the end of winter break.

If anyone has some more usefull information about making the N/A (S5) harness work with a JDM S5 T2 engine, please let me know. Thanks

 

******If anyone has some more usefull information about making the N/A (S5) harness work with a JDM S5 T2 engine, please let me know. Thanks ***********

Sure. Look at the Control Unit pages in the FSM and compare the pinouts for the n/a vs the turbo pinouts. I doubt you'll find much of any diff on a S5 EM harness.

 

Also, this is a little off the subject, but lets say I put a N374 ECU in my Aspec 89 GTU, (just to see if the Jspec ECU is dameged) how would my car run at the point? Or is that not a good idea at all? Just wondering...

 

what is an EM harness? engine management? good luck on your swaps everyone, sounds like fun projects.

 

It's the emissions harness. That's the harness that feeds the fuel injectors, afm, boost sensor, water thermo sensor, air intake sensor etc. The Engine harness does none of the above. Zip of it. It's shown in the free online FSM.

{F} Front harness

{E} Engine harness

{I} Instrument harness

{R} Rear harness

{EM} Emissions harness

{Me} Meter harness

{St} Storage harness

{A} ABS harness

{In}interior light harness

{Cr 1} Cluster switch harness L.H

{cR2} Cluster switch harness R/H

and a few more

 

seems like the emmissions harness is transmitting controls of the engine, so what the hell does the engine harness control? couldn't someone make their own harness if they had the connectors and pins already? maybe it's just not feasible, cause I haven't heard of it unless it's controlling a standalone
.
I appreciate your educative reply, I may go look at that online FSM, but I gotta go do some homework for now.

 

Lol how about someone answering my ECU question? =P

 

Yes this is a little pain in the ***. I am putting a jspec in my 88 engine and harness trans al 89-91 Finally got the wiring situated now have low comp in front rotor. I had to extend certain connectors and find where everytrhing went in the body harness verses where everything came or went to the ecm.

 

Where did you buy your Jspec engine from?