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-   -   s4 motor in s5 car (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/s4-motor-s5-car-467862/)

dr. gonzo 09-29-05 05:27 PM

s4 motor in s5 car
 
okay, sorry, not the most knowledgeable here, but wondering, how can you make the s4 distributor thing (not sure exactly what it is but is in place of where a distributor would be) work with the s5 wiring harness that is coming from the firewall closest to the drivers side...not the main engine wiring harness. i need to know because what i am doing is using the s4 main harness ecu and motor in the s5 body with the wiring harness that operates the lights and such. any info is greatly appreciated, and anything that im not considering and is mentioned would be a great help. thanks alot people.

Madrx7racer 09-30-05 01:31 AM

?...............take pics cuz you lost me.

zerrorx7 09-30-05 02:36 AM

thats ur cas..i would just one from a s5 engine...thats if they dont hook up...i think thats what u ment.

dr. gonzo 09-30-05 10:41 AM

Awesome...yes, That Is What I Was Saying, It Is The Cas. So I Cant Use The One From The S4? I Have To Pull One From An S5?

HAILERS 09-30-05 11:20 AM

The wiring harness on the engine that feeds the solenoids and the fuel injectors is the EMISSIONS HARNESS. See the FSM for the names of the different harness in the car.

A series four EMISSIONS HARNESS is NOT plug and play to a series five FRONT harness. It's only doable if you DEAL with the mating plugs and swap wires/add wires/ eliminate wires etc.

Also somewhat related, a series four turbo EMISSIONS HARNESS is not plug and play with a non-turbo FRONT harness. Wires need to be dealt with on X-15 and X-16 on a 87car, or FEM-01 and FEM-02 if a 88 car. I only mention this because of several post related to this recently on this forum.

FEM means Front harness to Emissions harness. As in the mating game.

spitfire7 09-30-05 01:15 PM

i did that to my car, and to get it to work i had to either get a haltech or change all the wireing from an s4 to my s5. it worked but if u want ur ac and heater to work ull have to change it to an s4 heating system. 800 haltech or a junkyard s4 entire electrical system. good luck

dr. gonzo 09-30-05 02:05 PM

Ahhh Hell...now That Ive Looked At It Im Thinkin Im Gonna Have To Switch Out And Repin The Entire Dash Harness....its Lookin Like There Are Several Things On That Specific Harness That Is Important For The Car To Function. Im Not Caring About The Guages Working, Anything Like That. Just Want To Get This Thing Mobile. If Anyone Knows How I Need To Wire This The Information Would Be Highly Appreciated. And Thanks For All The Help So Far, Its Nice To Have Somewhere To Speak To The Rotary Gods.....seems Noone In My City Has Any Clue As To Why There Are No Cams Or Pistons In Something That Outruns Them. Some Peoples Kids.....

HAILERS 09-30-05 02:32 PM

Just leave the series five harness'es in place and not use any series four harness at all. Nor the series four ECU.

The things that make an engine run will work just fine. Some things on your series five harness won't be connected up. Like the VDI plug, since the series four had none. I"m taking to heart what you said when you said *I just want to get this thing mobile*

I take it you know that you'd have to swap front covers with the omp? Yes. Did your old omp on the series five work? If it did then do that. IF it did not work.....ugggggh. A lot depends on IF the omp on the series five was working or NOT.

On the other hand, if you were real familiar with RX and a little bit about wiring schematics, you could make the series four ECU and series four EMISSIONS HARNESS work with the series five car and series five FRONT and ENGINE etc harness. You'd have to think it out for some time though.

dr. gonzo 09-30-05 04:48 PM

no love on the s5 omp. its out of order. no cash to get another, and have an s4 swap sitting here. have an s5 shell. need to put the two together

dr. gonzo 10-02-05 05:26 PM

any ideas anybody?

emac 10-02-05 06:57 PM

use the s5 wiring and s5 omp, as far as i know you dont have to screw with the harness at all. just use the s4 block and bolt everything s5 onto it. the ecu won't know the difference.

NOPR 10-02-05 09:07 PM

well, the easy option would be a standalone. but thats $$$$$$.

inflatablepets 10-02-05 10:13 PM


Originally Posted by emac
use the s5 wiring and s5 omp, as far as i know you dont have to screw with the harness at all. just use the s4 block and bolt everything s5 onto it. the ecu won't know the difference.

Prettymuch. Gotta block off a few things though. Too bad the person can't use all S5 externals. It works well in my car.

dr. gonzo 10-03-05 08:05 AM

What Needs To Be Blocked Off? And If I Cant Use The S5 Omp, Can I Just Block Off The Oil Lines And Run Premix? I Dont Wanna Do This But I Will If I Have To In Order To Get This Thing Mobile. I Just Need It Running.

dr. gonzo 10-03-05 05:54 PM

anybody got a clue?

Kingbob 10-03-05 06:06 PM

I'm sure you can hook together the s4 Emissions harness to the s5 body harness. Go to iluvmyrx7.com and look at the wiring diagrams for the two cars, compare, compare, compare, compare and then compare some more. Then a week later you should be able to figure out what you need to splice together to make it work. It worked for my s4 into s3 swaps

HAILERS 10-03-05 06:44 PM


Originally Posted by dr. gonzo
What Needs To Be Blocked Off? And If I Cant Use The S5 Omp, Can I Just Block Off The Oil Lines And Run Premix? I Dont Wanna Do This But I Will If I Have To In Order To Get This Thing Mobile. I Just Need It Running.


A bad omp in a series five will cause the car to run real dodgy. It's an electrical problem not mechanical. They call it the Limp MOde.

The question raises its ugly head........how do you know the omp is bad? If you had driven it in the limp mode you would not have asked your question about the pump. If it's just leaking, that's not a large problem.

If the omp is in the limp mode (electricaly bad omp), then you can't use it at all. The ECU sees the problem with the omp is it is an electrical problem and delibertly make the car run bad. Just good enough to get you home.

A bad omp means you can't use the series five ECU. You can't use a series four ECU unless you do some wiring alterations to make the series four EMISSIONS HARNESS mate with the series five FRONT HARNESS. That path takes both a series four schematic and a series five schematic and TIME. Plus a touch of skill.

You seem to be going up a creek without a paddle.


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