FC_787

Hello I'm getting parts for a N/A to TII swap but my N/A main wiring the one that runs from the battery to the ecu is in bad shape from the previous owner butchering the thing. Question is if I get the main harness from a TII and install it for now with the N/A ecu and engine will it work without issues?

Car: 86 GXL no mods

RotaryRocket88

iTrader: (7)

There is no wiring harness running directly from the battery to the ECU. On an FC, the main harnesses are:

Engine harness (E) : battery, transmission, CAS, main fuses box
Engine Management harness (EM) : ECU and sensors
Front harness (F) : Many things from the interior electronics to engine bay relays

If your engine harness is the one that's damaged, it can be replaced with another NA engine harness. That harness has little bearing on a turbo swap other than the alternator plug, which is on the TII E harness, but on the NA EM harness. I always suggest keeping all of the NA wiring anyway.

https://www.rx7club.com/2nd-gen-arch...etails-813825/

More links in the 2nd gen FAQ

dwb87

iTrader: (22)

If you're referring to the engine harness, you can swap in either an N/A harness or TII harness. The CAS is the same, all of the ignition coils are the same, main relay is the same, fuse box is the same, etc...

And a tip about the engine management harness: You can use the N/A (EM) harness for your TII swap! Less money to spend. ;-)

S4 Vert

Your advice seems to be the best and most clear, I read the other posts and every body adding their 2 cents made what should be simple more complicated for me.
I just installed an S4 13B T in my S4 88' vert, the motor came complete with an uncut and attched harness. All I had to do was pull my n/a ecu and harness and install my n332 and drop in the 13B T harness through the fire wall.
I do notice a slight difference, like as you stated the wires for the alternator are not there. How do I wire the alternator?
And there is one less connector on passenger kick panel on the 13B T harness.
Should I use one of the green n/a connectors along with the white 13B T connector on the passenger kick panel. Before the two n/a connectors were connected to the green connectors on the passenger kick panel.
Also could you tell me where these two connectors go? They are on the engine bay side of the wire harness that leads under the dash. Sorry if I made this sound confusing, this is my first RE swap and I am performing it by myself.

Thank you

misterstyx69

iTrader: (142)

Those 2 plugs on the inside engine bay look like cold start assist bottle and the Cruise connector.

S4 Vert

Ah. I still have my cold start assist unit, I do not plan on using it, but I'll compare the receiving connector on the unit. Same with the cruise control, I do not plan on using it either.

Thank you very much.

S4 Vert

I checked the two wire cinnectors at the firewall, and yes they are for the cold start assist and cruise control units. One less unknown that is now in the know.

RotaryRocket88

iTrader: (7)

New wires have to be run for the alternator plug.

I think the white plug in your 2nd picture is for the knock box (not present on an NA, but you can add one). It's pictured on page 50-26 of the S4 wiring diagrams, and has G/Y, B, LG & B/W wires.

I skimmed the diagrams looking for those green 8-pin plugs, but the closest thing I found was for the blower unit, which is not related (pg. 50-65). You're sure the NA EM harness plugged into them and not another harness? It's been a good 5+ years since I swapped an EM harness, but I don't remember those.

Page 50-29 has all of the connectors on the NA EM harness.
Page 50-32 has all of the connectors on the TII EM harness.

You should be looking at FEM-01, FEM-02 (as in F to EM harness connectors), the ECU plugs, the atmospheric pressure sensor plug and the knock sensor plug. Compare the pin number and wire color of those green plugs to figure out what they are.

http://www.rotaryheads.com/PDF/2nd_g...ng_diagram.pdf

S4 Vert

Correct the two green connectors is not a part of the ecu harness, the wires go into the passenger kick panel so that makes sence that they would be for the blower unit. The white connector does fit into the yellow receiving connector, which is why I thought the two green connectors were a part of the harness. I located the b/w and w/b wires on the harness that I need to run the new alternator wires to.
Thanks for the information, I will study the diagrams. So far I made a mess with the harnesses and most likely will need to scrap everything and go with a stand alone unit.

fdlover1994

A harness isnt that much i would get a new one so u want have any more problems and have to go back to it.

misterstyx69

iTrader: (142)

In a perfect world,yes, a New harness would be just peachy.But we are talking about 25 year old cars that are getting harder to get parts for.
Have you priced a New harness for your FD yet?..Can You afford that?..
Personally,I see the Typical FC owner as a Guy on a Budget..Go fast and spend as little as possible..lol.
I cannot see guys spending money on a harness that cost more than what they paid for their car!
My S4 N/A to TII swap was done with the Original N/A harness.I put on new injector clips,lengthened the TPS wires,etc..
IF you do this make sure you are paying attention.That is why I stress,mark everything,take your time.Do it right the first time.

S4 Vert

I actually lucked up on a very good S4 TII harness that I will not destroy ha ha! I've learned by my mistakes, my first rodeo and I got bucked off, but I'm back on. I was prepared to buy a Haltech P1000, which I still will buy in the furture once I start adding on aftermarket parts.

My goal for now is to just get it up and running, break in the new clutch, and do some body work, paint, and more suspension upgrades.

Thanks for the advice and support guys, it's good to know help is just a "post" away.

S4 Vert

Ok...I have my replacement s4 tII harness in place, I installed the b/w, w/b wires for the alternator. Before I go any further, I have a few questions.

In order to get the water tempurature gauge to work, I have to relocate the light green wire from the tII x16 emissions harness to the empty plug on the bottom row third from the end on the n/a x15 emissions harness correct?

How then will the knock control box get a signal to the R plug on the n332 ecu harness?

Do I need to run a wire from the R plug of the n332 ecu to the now empty plug on the x16 tII emissions harness?

I am confused as to what wires I should relocate and illiminate. I have not touched any other wires besides the wires needed to install the new b/w, w/b wires for the alternator. I bought a knock control box too, I have not installed it yet though. It's straight forward, but I want to take care of the water tempurature gauge wires and the knock control box wire that runs to the R plug on the n332 ecu.