Orbital

I looked around and didn't really find anything, sort of hard to say since I hear about people doing these swaps all the time. Maybe I searched for the wrong terms but here is my situation.

I have a 79' GS and I'm doing a S5 n/a engine swap and to also go fuel injected. I want to do a complete swap, basically changing my engine bay and the dash cluster into an S5. I have the following parts...
S5 ECU
S5 Main Fuse Box
S5 injectors
S5 Coils
S5 LIM/UIM
S5 Circut Opening Relay
S5 Main Relay
But I'm not sure what else I really need, other than the engine harness, dash cluster. So for those who have done a similar job, please help me out by telling me what else I need/what needs to be done.

steve84GS TII

Been asked a thousand times in the last month.....

I have done it,I drive mine everyday and its fully CA legal and complete with stock EFI (mines a S5 TII).

There are S5 specific items you have to adress when doing this swap.Do a search with my handle in the terms and you should find a plethora/cornicopia/War&Peace sized novel of posts, in the last year listing the S5 items I tackled........like the S5 OMP front cover mod,FC intank fuel pump mod and the left side/right side wiring mod.Youll need everthing from under the hood,bascially anything that plugs into the left and right side engine harness'.The S5 ECU is smart and itll know if something is missing.Theres a S5 N/A in the Windsor P-n-P right now if your lacking pieces.Not too far away from you if you need more parts.The S5 dash cluster isnt required to make it work.Itd be a cool swap,but would also be more work.The gauges run off their own senders and have no connection to the ECU/EFI.

Its not super hard,for some reason I have one of the very few S5 swaps around.The S5 stuff is great,albeit expensive and harder to find.The N/A S5 is a hoot to wind out,in a light little SA itll rock.If you can make it CA legal like me,itll be a killer ride you wont have to worry about getting busted in...thats how I intended mine to be, and it is.

Orbital

Exactly why I am doing this project, but I don't know all of the specific items i need which connects to the two harnesses to make everything work. If you could help me make a list or something for me to get, I think that would help me out a lot.
Thanks for the info about the cluster, a friend of mine said I had to do a s5 swap because the gauges wouldnt read it since the engine is different/ecu. Saved me a bunch of time and money.

Oh yeah, I'm wondering how you were able to put in the right side engine harness since there is no hole in the body for you to connect the ecu.

RacerX7fb

My S5 n/a swap is inevitable...whenever I come up with enough cash for a complete rebuild. I will also be doing the complete transfer and get it referee'd for CA. Right now the S5 intakes on my stock SE block will do. Good luck with the work.

steve84GS TII

The big right side harness takes care of the majority of the ECU/engine connections.My 84 already had a hole for the 84 engine wiring harness,but its not hard to make a hole with a drill and hole bit.Itll ruin the bit,but itll cut through sheetmetal easily enough and make a perfect hole.

Heres the basics.........

Right side harness......
AFM
Boost sensor
All engine related sensors like TPS,OMP,ACV,VDI,BAC,CAS,rats nest,injectors,air temp,all the engine mounted stuff.
Basically every plug on the right side harness must lead to something.The exceptions are the bright green plugs which are test connectors and the yellow plug which is the fuel pump test connector.
The baro and knock systems are built into the ECU on the S5,which is a nice setup making it simpler to mount/wire compared to the S4.

Left side harness.......
You must make this one yourself as the FC harness is hopelessly tangled amongst the dash harness.Just cut the last yellow ECU gang plug off a S5 car and leave a couple inches of wire on the plug so you can ID each wire color to determine its function.Many of the wires lead to stuff that isnt needed for an FB swap,such as AC/PS relay,blower relay,milage sensors,AT junk,foglight relay,ect,ect.Once identified,these wires can be de-pinned from the gang plug and forgotten about,which simplifies the job by reducing the number of wires you have to deal with.The neccesary wires will lead to the following items....
Coils w/ignitors
ECU main power relay
Circuit opening relay.
Constant power
Fuel pump(the TII also uses a fuel pump resistor pack to vary pump voltage and output,the N/A just turns the pump on or off.So your pump wiring will be easier.

Use the factory service manual to take care of all this stuff.There is one page in there that will lay out EVERYTHING you need to take care of the wiring,here it is,page F1-8........

http://www.teamfc3s.org/main/factory..._non_turbo.pdf


For the gauges,just re-use the senders from the cars old engine so they run the gauges as usual.The tach and speedo are a no brainer.The voltage and fuel level are also not an issue.The temp sender might not fit in the S5 rear iron.You can make a threaded adapter to fit the 79's sensor in the S5 block,or do like I did and just drill/tap a new hole in the back of the waterpump housing outlet for the 79 sensor.This is the hottest part of the engine,and an ideal place for the temp sensor to take a reading.The 79 has no oil pressure gauge,but there is still a place to screw in a sender on the S5 engine,so you can add an oil pressure gauge....or try adapting an 81-85 gauge cluster.That would likely be easier than the S5 cluster swap.

immanuel__7

iTrader: (8)

what about the mounts im doing a s5 TII dose the engine and trans mount like the 85na gs? do i have to use my gs oil pan,

Orbital

I dont think the mounds will line up like your gs, and the gsl-se oil pan is needed for the transplant.

Also, I know that my 79' Distributor wont work for this setup, so what do I use to replace it?

steve84GS TII

The FC oilpan and mounts are not compatible with the 1st gen steering and crossmember.To mount the engine,youll need a GSL-SE oilpan and GSL-SE front cover.....thats where the S5 swap gets tricky.With a S4,you can just bolt up the mechanical OMP and drill a hole in the SE front cover.Then mount the engine like any 1st gen engine.With the S5,the big electronic OMP cannot bolt up to the SE front cover,and you cant delete the OMP because the ECU will know and itll go into limp-home mode all the time.I had an SE front cover heli-arc welded up,then machined flat and redrilled/tapped to accept the 3 bolt pattern of the S5 OMP.Then I drilled and tapped the extreme front right corner for the turbo oil drain.You wont need to do that mod,but you will have to mount the OMP,the S5 engine wont work without it.There are only 2 ways around this if you want to keep the stock ECU....
1st...Do a complete FC front crossmember/suspension swap.Its a big job and not many have pulled it off,but it gives you a LOT of upgrades.Search on it.....
2nd....Plug in the S5 OMP to make the ECU happy,then block off the OMP pad and pre-mix.This will work,I did it for a short time.But I cannot garuantee it to be a permanent fix.The OMP internals will still be moving and working,but without engine oil circulating through it there is little/no lubrication for the moving parts.

All the 2nd gen engines use a CAS instead of the distributor.The CAS works with the ECU to take care of all timing duties.On the S5 engines,the CAS is wired through the big right side harness,which makes it easy to hook up.It will drop right into the GSL-SE front cover.

Orbital

Because I'm doing a N/A swap, I was told I could use any first gen front cover, not just the -se. So I'm using my 79', the CAS will fit that too correct?

steve84GS TII

For all 2nd gens,N/A or TII they are the same basic EFI operating system.

The fact that the turbo engine has a turbo,is just about the only thing that makes the two different.Both types of S5 engine use the electronic OMP and both require the same front cover mod in order to maintain the stock ECU.The only difference between you and me is that you wont have to drill and tap a hole for the turbo oil drain,but you will still have to retain the electronic OMP to keep the S5 N/A ECU from going into limp mode.
That means whatever cover you choose,it will still have to be modded to accept the S5 OMP and Im not sure if the 12A cover will work since the oil delivery hole and OMP gasket type is different than on the EFI engines.Thats why I choose the SE front cover to do my mods on,because the sealing method,oil hole and drive tang for the OMP is the same on all EFI rotaries.It MIGHT still work on a 12A cover,but I couldnt say for sure.

RacerX7fb

Steve you are so patient and helpful

Orbital

Very, Let me thank you for helping me this far. but... I'm sure I'm going to have lots more questions for this project =]

steve84GS TII

Its no problem.
Ive kinda built a rep for being a pro S5 guy.Id like to see more 1G's running these engines,and I know there arent many that are,so Im kinda the go-to guy.Not to mention your in CA,so there isnt much room for error if your gonna build a smog legal powerplant.

craigw1

for the record, i considered doing the s5tii swop....but starting off from the wrong base (ie not a gsl-se) meant a very costly swap. Also, here in SA we swear by microtech, which is about $1000. I then thought about going fuel injection and using the CAS and leaving the turbo...but then i still needed some aftermarket system. In the end I then just decided to go 'old skool' and go with the std dizzy from my 12A, a nice big weber 48ida and rb header. I can only guess that my setup has been much easier to hook up and cheaper.

Eventually when the budget allows I would like to complete a tii swop.....but I am going to try my best to get hold of a gsl-se to start from first.

82transam

iTrader: (18)

Yea steve you have been very helpful to us, I am getting closer to doing my 90 t2 swap and you've been a great help with the fuel system etc. One question about the wiring, the wiring going to my ecu is uncut, however the wiring down on the driver side of the engine, the stuff that includes the starter wire and alt wiring was cut. Is there supposed to be a big connector there that the custom left side harness you were talking about goes to? I don't have a t2 readily available to look at... Thanks

steve84GS TII

The left side harness is all tangled up under the dash of the FC.It includes all kinds of other items besides the ECU wires you need to connect, to make the engine run.
One could extract the entire dash harness and strip it down to remove all the uneeded stuff,but its MUCH easier to....
1...Cut the 3rd ECU gang plug at the ECU
2...Gather up all the underhood parts and their plugs (coils,fuel pump relay,main relay,fuse box,circuit opening relay)
3...Lay out everything on the floor and solder new wires from the ECU leads to each of the component's plugs. All the wires are color coded,you cant go wrong.Using the FSM,youll know the proper color and position of each wire on the ECU gang plug.Any other wires left are for un-needed components and should be de-pinned from the yellow gang plug,to prevent any shorts.
4....Once all the minor leads are set,mount all the components under the hood,run the harness through the firewall,and plug it in.
5....Then youll need to wire up the large leads for the FC main fuse box and main ECU relay.The FC fuse box will power/fuse all the regular FB systems as well as the new FC systems related to the ECU and ECU mian relay.The main relay provides the ECU with power as well as providing a large gauge power wire for the 4 fuel injectors and all the rats nest solenoids.All of the solenoids/injectors on the engine,feed off two common power lead,which are the large black/white and black/yellow wires.The ECU controls the thin ground wires for each of the components independantly,depending on if that item should be on or off at a given time.But the main ECU relay provides the power for all of them,all at the same time.Thats why those 2 wires are much bigger and need a large power relay to switch them on.

Its all quite simple once you look at it all in person and examine the FSM wiring scematic.89-91 S5 RX-7 Factory Service Manual......Page F1-8 for the N/A and page F2-8 for the turbo.

The stuff for the left side of the engine like alternator,starter and gauge senders should all be left alone.Just utilize the stock FB wires for that stuff,if its been cut,then youll have to rewire based on an FB diagram.The 2nd gen EFI wiring is not connected or concerned with any of that stuff,there is no plug.Thats the great part about the FC engine swap.It can be done without a single splice or connection into the FB's original harness.If I hooked it up to a battery,I could run my TII engine sitting on a stand with the harness' I have,they are completely independant of the rest of the car.

82transam

iTrader: (18)

Hmm, guess I'll have to look at a FC in person again, I must be missing something... I have 3 yellow plugs going into the ECU, but I don't see where they would connect with anything other than engine components, they all go into a big piece of wire loom and off to the engine they go, I can't put together in my head how they interface with the left side harness... Guess once I dig deeper into this thing It should make more sense, and I have the FSM, definatly very helpful. Thans again steve

clean85owner

Slight thread jack: I have a motor that I am trying to get into my '85 GS. It's S5 irons and FD housings, and when I put my -SE oil pan on the bottom, the majority of the bolt holes don't line up for some reason.

Any ideas as to why my -SE oil pan isn't fitting correctly?

steve84GS TII

What front cover are you running?
The GSL-SE oilpan will only fit a 13B thats fitted with a 1st gen front cover......which youll need anyways to mount up the engine 1st gen style.The S5 irons shouldnt matter,my engine is S5.And the FD rotor housings are very similar to the S5,they are othen used in place of older rotor housings.You SURE the irons are S5?Get a 12A or SE front cover on there and try the pan again.

The big honking harness on the right side of the car,IS ALL to the engine.Check the FSM page F1-8(N/A) or F2-8(TII).
That big harness is all the terminals numbered 2 and 3, with a letter afterwards.The last plug is all the terminals numbered 1, with a letter afterwards.That last yellow plug leads to the left side of the car under the dash.Its not at all connected to the big right side engine harness.

The wires/pins (some you dont need at all),on the #1 left side yellow plug,go to places all over the car,thats the hang up.Those extra pins include....
milage sensors(gauge cluster)
AC relay(dash)
blower relay(dash)
headlights(dash)
fuel pump relay(pass side of car)
cruise control signal(under dash)
foglight relay(front of car)

The reason all that chassis electrical stuff is wired into the engine ECU is because the ECU can better control the idle quality if it knows when major electrical draw items are activated.When you flip on the heater,fog lights,ect...it makes the idle drop from the alternator load.If the ECU sees the switch thrown before the draw actually happens(milliseconds),it can compensate for the load and keep the idle stable.Personally,I think its stupid and Ive never seen any idle fluctuations that are substantial and make me wish I had not deleted the circuits.....its over-engineering and its pointless.

Like I said,you could dissasemble the entire dash harness and pickout/snip the wires you need/dont need,but its easier to just lay out new wires and start from scratch.It only ends up being about 12-15 wires that youll have to lay.Thats a tiny harness compared to what you'd be wrestling with the multiple,conjoined harness's under the dash.

clean85owner

The motor has a 12A front cover on it. We wound up just making a template of the bottom of the motor and redilling the oil pan were needed. The same thing will be done with the gasket, and then it will get siliconed to hell and back before being bolted up.

Orbital

Hey Steve, do you mind sharing with me the driver side of your engine bay? I want to see how you did the setup, so I don't do anything foolish. Id understand if you refuse.