I've seen a few 1JZ converted FC's running around, the "other board" also has a few of
them, I'm shelling my car right now gearing up for this conversion on a spare FC
shell I have lying around, but was curious how people wire their harnesses? Are
they using a 1JZ harness? a FC Harness? a spliced up fc/1jz harness? Not sure,
never done this before so I'm in the dark.....

My thoughts are.... They're using a stocker or modified ECU from a 1JZ and converting
the endlinks (Engine Out/In) on both sides of the harness to plug up to a 1JZ? I have
flushy headlights so keeping popups isn't necessary, but for the people who DO keep
them, I was trying to figure how they got them to operate? Since the popups are the
only thing I can think of that is in the engine bay (that I can think of off the top of my
head) you'd think you could use a full 1JZ harness for your bay, then convert your
cabin harness to accept your plugouts for your cluster and whatever else? Logicon
I'd guess? </ramblings>

Dunno guys, tell me what you think.

 

you leave your rx7 body harness alone. the 1jz engine harness only needs a total of 5 wires outside of it's own harness to operate power , ground, batt constant 12 volts, starter signal and the alternator wire that originally went to your rx7 alter nator goes to the 1jz alternator. done thats it no hybrid harness and no extra splicing also you will want to wire a relay to turn on your fuel pump. now if you want the stock gauges to work, you have to use your rx7 senders ie- oil pressure and rx7 temp sender, depending on what fc you have you will have to run an extra wire for the temp sender on s5's its the yellow with red stripe on the yellow connector in the passenger foot well. i've wired most of the 1jz rx7 swaps in south florida, any questions i'll be more than glad to help pm me .

 

Dude! You are the man, thanks for the reply it is much welcome.
So, just to make sure things are crystal clear, I'll be using the 1JZ
harness and 1JZ ECU? Or is it an RX7 harness with the 1JZ ecu, then
swap the harness to ecu heads and harness to engine heads? The way
you said it made it sound like it could be either, so I just wanted to
clear it up. I assume that you mean a RX7 harness and 1JZ ECU
though.

So either way, I'll need to route an additional five wires (if you could
tell me what resistence/guage of wire you've been using, and for what
I'd be extremely grateful btw) to operate the power, ground, and etc
to the engine.

Now a few stupid questions, if I'm not using an RX7 ECU, how do I
control things like my logicon, door chimes, lights, and other useless
things? Just a random question but one I thought I'd throw out there.

Also, just to complicate things a bit more, I'm using a JSpec harness
from a Turbo S5 (cars converted RHD), how much is that going to
complicate things?

I doubt you have any diagrams, but if you maybe do.... Thanks
for doing a little hand holding through this, really cool of you man.

 

there are three harnesses that run in your engine bay....the front harness, charging harness, and the engine harness.....you have to use the 1jz ecu to run the engine for fuel and timing but the front and charging harness you will leave in the rx7. hope that clears you up

 

Don't all of the harness' end up back at the ECU though? I thought that form your ECU
they Y'd out into seperate harness'. I'm taking apart my car right now, and should have
looked while I was doing it. Just curious if this info is vaild for both VVTI and Non-VVTI
engines, since there are two seperate kinds. Had popped into my head was what was
the difference between the front/rear sumped engines, and will I be able to use either
as esaily or if one would require more modification than the other. BTW thanks guys,
I appreciate you straightening me out.

 

Just picked up a used evo 8 OEM FMIC super cheap, i'll be mounting it asap. They flow really well, we used to push over 500awhp on evos with them at WORKS years ago :P

Time to put that POS mr2 sidemount back on the shelf! restrictive pos!

 

THIS MAN!


that's exactly what i did. works great

 

Oh but I used the stock 1jz temp sender, works fine with the rx7 gauge

 

Hey man do you have a wiring diagram for that or could you explain which wires on the body harness yellow plug need to be linked into the engine loom inside the car and what needs to be run to the ecu loom by the alternator.
Thanks in advance for any help you can give me

 

how u get the tach to work? and other stuff like a/c ,speedo,?

 

For the tach and speedo you will probably have to use the dakota digital signal converter boxes I would imagine.

 

Nope!

Recalibrate the stock tach.

http://grannys.tripod.com/rx7tachrecal.html

Speedo was plug and play for me with stock cable and r154 mechanical sending unit.

 

i skimmed the thread....

Soo the best bet is to use the 1jz engine harness for everything. Ditch the oem rx7 gauges and run autometers from the 1jz harness/direct from the engine. This way the gauges are reading straight from your engine and there's no worries if your conversion boxes and what not are telling the OEM Rx7 gauges the correct readings or not. Thats how i have my gauges setup, all autometer straight to the engine, strictly mechanical, and i trust them. That being the key factor...

PS, your headlights should NOT be the deciding factor on your engine swap, lol.

 

Agreed.

Yes. Your charging harness and body harness will be retained. Same goes with any swap. The main part is knowing what functions the ecu you're using needs to run properly. Coolant, air temp, air mass/flow/pressure, throttle position, oil pressure, crank angle sensor/dizzy, cam angle sensors....the usual stuff. If all your connections meet the requirements of the ecu and it gets power, you're good.

Wire the ignition, fuel pump and starter up as if it was wired in the car the engine originally came in and you're gravy.

Um, it's electricity. It travels through wires, makes conections, flies through resistors and with a switch and some 12v power you can wire your lamps and motors independant of anything. Whether your flush lighted or stock pop ups...lol.

You guys think entirely too hard about ****. Break it down into slices of cake, not a statue that's been crumbled into dust that you have to re-assemble with super glue, a microscope and tweezers. It's time consuming as hell and somewhat frustrating if you're new to it but the more you play with wiring, the easier it is!

Edit: Most would LIKE to use stock rx7 cluster for the look, feel and oem-ness. For all 'get **** done quick' purposes, i'd go your route (which i am) and run aftermarket gauges and an apexi rsm....

 

Speedo was plug and play for me with stock cable and r154 mechanical sending unit.[/QUOTE]

I just finished my 2j swap on my 88 fc with r154 tranny, my speedo is not plug and play, could u elaberate what you did to plug the stock cable into the r154, is there different sizes of speedo gear housings in fc's mine is smaller than the r154 port, it is also shorter. what parts should I get to make the factory speedo work, I have the factory diff in the car right now I believe the factory ratio is 410, any help with the speedo would be great.

 

stock cable and r154 mechanical sending unit.

JUST the cable from the RX7

Went right into my speed sender. My r154 came with a electronic sender, took it out of for a mechanical sender from a USDM mk3 turbo supra that had a mechanical speedo drive.

Not sure what you aren't getting.

 

Tons of stupid in this thread.

All you need to do is power the 1jz harness. Use your stock main relay/ignition switch. Power the fuel pump via relay or however you want.

Wire up the stock gauges to work. I already explained how to do the tach. Speedo can be plug and play. Your temp gauge can be wired to the stock 1jz sender - works well enough.

If you don't own a multimeter - sell all your car stuff and get into another hobby. You obviously aren't really into this.