keenangodburn

im in the prosses of installing a tII motor in to my 87 n/a. while hooking up the engine wiring i realized that the wiring harness that is attached to the motor (right side) doesnt have a plug for the alternator. the car i took it out of (86 n/a -> tII swap) has the alternator plug on the drivers side harness. so i took the drivers side harness off of the donor car and tried to plug it in to the 87s body harness. everything plugged in fine until i got to the cylindrical connector just behind the drivers side strut tower. then i realized that the donor harness has a six pin plug but the 87s plug is a four pin plug. i dont know what to do. please help.

i think the turbo II motor is s5 (the throttle body has two buterfly valves on bottom and one on top _-_. the original n/a s4 is the opposite. two butterfly valves on top and one on bottom -_-) hope this helps.

Blake Bruning

iTrader: (1)

You Maybe able to help me, I know this isn't a help to you though. I am trying to Swap a JDM T2 s5 ebgine in my '87' N/A. I needed a wiring harness becuase Mine was cut. I guy sold me one and I believe they are different. Are the N/A and T2 Harnesses different? as far as are they wired backwards? I know you are having one plug problem, but other then that, do the plugs match up as far as the order of the plugs and lengths? I mean, are the T2 vs. N/A Harnesses wired and structured Backwards to each other? Or is it just USDM vs. JDM Backwads? Oh yeah, as far as your plug crisis, can't you just cut and splice that single plug? As long as the right wires get connected right should't it work?

HAILERS

If the EM harness on the engine mated with the series four Turbo ECU and the FRONT harnesses two mating plugs, then it was a series four Turbo EM harness.

The alternator plug is in the E harness on a turbo car and it's in the EM harness in a non turbo car. Two wires.

If you installed the EM harness you had to route it thru the firewall bulkhead. So you would have noticed two orange/yellow plugs just inside the passengers foot well on that EM harness and how they mated with the FRONT harness.

Those two plugs have a reference designator. In the online wiring diagram they are called FEM-01 and FEM-02. IF you look at the free and online wiring diagrams you'll notice that those two plugs are not pinned the same b/t Turbo and non turbo EM harness.

You'll find these two plugs and their pinouts on page 50-38 of the WIRING section of the free FSM. The wires shown with ( ) around them are PECULIAR to Turbo cars. Notice there are a number of those ( ) in both of those plugs. Only the (BrR) will cause real bad heartburn. It's in FEM-01 and is the third wire over from the right on the top row. Just below it is the (B) wire.

Go to Rotary Ressurections site if you don't follow the above, and there are instructions on what to do with the harness in a swap on series four cars.

The two wires that can cause trouble by this different wiring, are found in the plug that has 15 sockets/pins. You'll find a Black/White wire just above a White/Black wire in the FRONT harness side of that plug. Those are for the ALTERNATOR. So you route two NEW wires from the alternator plug to that fifteen pin/socket connector.

One thing you'll notice is that on the EM side of that plug, the wires are NOT Black/White and White/Black. They are brown/red and pure black (possibly brown/black in some cars). What you do is cut those two wires, the brown/red and black, about three or four inches from the EM half of the plug. Then you splice your two NEW wire from the alternator to those left over pieces of wire (the ones three/four inches long). Now your done. PUt the plug halve back together and now you have one wire from the alt mating with the black/white wire in the Front half of the connector and the other wire from the alternator mating with the white/black wire in the Front half of the plug.

Now your Turbo EM harness will work with the n/a Front harness and the car should start up and run.

For what it's worth, the harness on the left side of the engine that has the alternator plug on a turbo car, is the engine harness (E). I'd put the original non turbo E harness back in the car.

So go download the Wiring for the series four car from this site and take a look towards the back few pages where you will find the pinout for the plugs called FEM-01 and FEM-02 and if memory serves it'll show the wires I was talking about. The white/black and black/white .

If you leave the turbo EM harness like it is, mating with the non turbo Front harness, bad things will happen with that brown/red wire I mentioned above.

HAILERS

Here's a picture of the EM harness and the FEM-01/02 plugs location.

And two plug jpgs. The one called X-15 IS the same as FEM-01 and the one called X-16 is the same as FEM-02.

The wire colors with ( ) around them are in the Turbo EM and F harness.

In the X-15 plug you can readily see the B/W above the W/B. Those are the alternator wires in a series four NON TURBO. The turbo EM harness will have the wire colors in ( ) and are NOT alternator wires.

Every bit of the above makes sense to ME.

HAILERS

I've no idea why the jpgs did not show up. It's either a moderator problem or.....a moderator problem. Not my problem.

HAILERS

In the following thread I have some jps of the FEM-01/02 and what the wire functions are in the plugs. They may be labled X-15 (FEM-01) or X-16 (FEM-02)in that thread. The series four early FSM calls those plugs the X15...X16.

https://www.rx7club.com/forum/showth...t=jpg+attached

keenangodburn

thanks for all your help. i cut out the plug, and wires with the pins that connect to the orange connector. i havent started it up yet though.

keenangodburn

i noticed on the thread you provided the link to, someone mentioned that you also have to run a six inch wire somewhere. do you know anything about that?

keenangodburn

ok so the wire was the one that connects to the bottom of the oil filter housing. please explain? i really appreciate all your help.

HAILERS

He got his wire colors wrong. The water temp sensor wire is yellow/white.

If you used a Turbo EM harness in your na car, then the water temp gauge won't work. It won't work because that yellow/white wire in the Turbo EM harness goes to the plug called FEM-01,(fifteen pin plug) but on a non turbo car it goes to FEM-02( thirteen pin plug

So you find the fifteen pin plug on your newly installed Turbo EM harness. You find the yellow/white wire. It will be in the Bottom row of that EM harness, on the bottom row, third pin over from the end.

Then what that fellow did, was jumper that yellow/white wire over to the other plug FEM-02 (thirteen pin plug). Evidently he used a piece of wire six inches long to do that. It will mate with a Yellow/Black wire in the F part of the plug called FEM-02. The yellow/black wire will be found in the top row, on the end of the Front side of the plug called FEM-02 (X-16).

In the pictures I attached in that post, one is called X-15 in the pictures and one X-16. They are the same as FEM-01 and FEM-02 respectively. The early (GOOD) FSM schematics called those two plugs X-15 and X-16 and older (BAD) wiring schematics called those two plugs FEM-01 and FEM-02. This is just an explanation of why my jps are X-15/X-16 instead of FEM-01/FEM-02.

FEM has a meaning. It means Front to Emissions. The Front harness (F) is the one inside the car that runs from the passengers side to the drivers side, back in to the left side of the engine compartment and way up front of the engine bay. The Emmissions harness (EM) runs from the ECU into the engine bay and connects to the engine and the afm/boost senor etc.

FYI....The white/red wire that goes to the oil pressure sensor needs no adjustment to it. It is a part of the REAL engine harness on both Turbo and non turbo cars. The REAL engine harness runs along the left side of the engine bay/engine.

HAILERS

It's difficult to follow what I'm saying, but it should somewhat clear as to why one might not use a Turbo EM harness on a turbo swap to a na car.

The plugs might all mate up just fine and dandy, but the FUNCTIONS of the wires in the Turbo EM harness will not mate with the wires with the SAME function in the FRONT harness.

So adjustments have to be made by moving the wires in the plugs called FEM-01/FEM-02 so the right wires in the EM harness will mate with the right wires in the F harness.

Little has to be done to the wires in the plugs that mate with the ECU itself. The ECU plugs are not the problem. The OTHER two plugs on the EM harness that mate with the F harness are the ones that need attending to.

The wiring schematics in the 88FSM are not as clear as the ones in the 87FSM which is not available online. As regards the Turbo vs non turbo FEM-01/FEM-02 plugs anyway. That's another subject all together....the diff b/t 87 vs 88 FSM's.

keenangodburn

so connect y/w wire from FEM-01 to y/B on FEM-02 plug?
y/w y/b
| |
| |
| |
----- < connect wires together like this?
| |
| |
| |
FEM FEM
01 02

or take y/w completley out of FEM-01 and connect it to y/B FEM-02?
y/w
| |
| |
\ |
\ |
\ |
\ |
\|
FEM
02
FEM
01

or take both out and plug y/w into FEM-02
y/w y/B
| |
|
\
\
\
\
\
\
\
\
\
\
\
FEM FEM
01 02
or do i just switch wires in the plug positions?

keenangodburn

damn spent all that time on drawing diagrams and they all got screwed up...

HAILERS

Go look at the EM harness plug that has 15 wires in it. It's called FEM-01 in the FSM.

If it's a Turbo EM harness, it will have a yellow/white wire in the bottom row, third wire over from one end. So now you know about that wire.

Now go to the 13 wire plug and pull it apart. Look at the plug half that is a part of the Front harness. You should see a Yellow/Black wire on the top row and it'll be on the end of the top row. By hook or crook, you need to make that yellow/white wire in FEM-01 connect with that Yellow/Black wire in the 13 wire connector.

You have to remove the yellow/white wire from the EM harness and mate it with the Yellow/Black in the Front harness in order for the water temp to work on the gauge. The Yellow/Black goes to the water temp gauge FYI.

Here's a tip for after you get the harnesses plugged up. Get your old cas from your old engine and attach it to the plug for the cas. Key to ON. Everything connected up on the car. Spin the cas bottom gear with your fingers and listen for spark and the clicking of the primary fuel injectors.

IF you do not hear the clicking/sparking, then don't try to start the engine because it isn't going to start without spark. You do this spinning of a cas out of the engine with your fingers so you won't be wearing out your starter and putting undue wear on a engine that won't start.

The sound of the sparkplugs sparking may drown out the sound of the primary injectors clicking. Disable the coils by disconnecting the small white plugs to them, then spin the cas once more. You SHOULD be able to hear the clicking of the injectors now.

HAILERS

..

HAILERS

This is being written as a FYI for those swappers who don't seem to understand why you can't install a Turbo EM harness on a non turbo car and expect everyting to work right.

There are two plugs on the EM harnesses that are common b/t turbo and non turbo harnesses. In one of the last jpgs I pointed to them and called them FEM-01 and FEM-02.

There are wiring differneces in those two plugs b/t turbo and non turbo EM harnesses.

What are the differences????? Look at the two plugs in RED I attached in the above jpgs.

See the wires with the ( ) around them????? Say yes. Those are the wires that are different, and THEY are in the TURBO EM harness. The non turbo harness will have different color wires in those same sockets.

The different colors represent a different FUNCTION. You can see that when you look at the schematics in the FSM.

The only wires that can cause real heatburn, is the Br/R wire in the Turbo EM harness. See the (BrR)????? That comes FROM the boost sensor and is also spliced in to the Br/R wire going to pin 2B in the ECU middle plug.

See how the BR/R wire will mate with a B/W wire in the Front harness side of that plug???? Please say Yes. Well that B/W wire is from a 12vdx fuse. Meaning your going to be backfeeding 12vdc to the boost sensor and even worse, to pin 2B of the ECU. Pin 2B usually sees no more than 3-4vdc EVER. Not desireable.

In some of the jpgs I attached in a post above, I've identified most of the functions of each wire in the two plugs. Errors might have been made in a place or two. The BR wires for the sub zero system might have gotten confuse with the Start signal wire . I frankly don't care too much whether I did or did not get 'em confused. All one has to do is go to the FSM and check the wires out for themselves.

Even though only one wire can cause Heart burn, you can readily see there are several wire with ( ) around them. If you don't take action with each of those, then not everything will work as it should. Actually a few don't matter if you don't have pwr steeing and.......forgot the other.

See the YW wires? YW is for the water temp sender on the engine. It mates with a YB wire in the Front harness side of the plugs. The YB goes to the water temp gauge.

Look and see how the turbo (YW) is in one plug on the turbo EM hareness and it's in the other plug for the non turbo EM hareness. Water temp gauge isn't going to work, is it??? Say NO.

Then consider the other wires with ( ) around them. Trace them out on the wiring schematics and figure out if you do/do not need them to work.

There's not that many wiring schematics. You don't have to look at the RADIO schematics at all or THEFT and some other not relevant schematics. That cuts the number down quite a bit. Plus I've already ID'd the functions of MOST of the wires in the jpgs above. Just go to the schematic relevant to what I said the wire is used for..

https://www.rx7club.com/forum/attach...1&d=1187795982

https://www.rx7club.com/forum/attach...1&d=1187796027

https://www.rx7club.com/forum/attach...1&d=1187796092

https://www.rx7club.com/forum/attach...1&d=1187796146

https://www.rx7club.com/forum/attach...1&d=1187796198

That didn't work out as planned. This thread has those jpgs on it https://www.rx7club.com/forum/showthr...t=jpg+attached

keenangodburn

thanks for all your help. i know it must be frustrating hearing all these dumb questions but im new to rotaries and only 18 so just bear with me till i get this thing running.

keenangodburn

just for clarification when this modification is done the y/w wire will be completley removed from the 15 pin plug and connected to the y/B wire witch is connected to the 13 pin connector.

just want to make sure i fully understand everything before i start splicing wires.

HAILERS

Yes. If you have put a turbo EM harness in that car, you will find a Y/W wire in the 15pin plug, lower row, third from the end. You somehow make that one go to the 13pin connector, top row, end wire.

IF you left your original non turbo FRONT hareness in the car, you will find that there is already a Y/B wire in that 13pin connector (the half of the plug that is a part of the Front harness).

The half of the 13pin plug that is a part of the EM turbo harness probably will have a wire in that corner and should be a Lg/B wire. You want to eliminalte that Lg/B wire. Maybe cut the LgB wire a couple of inches back from the connector and splice a wire from the remanants over to the 15pin plug where the Y/W is. Get my drift?

https://www.rx7club.com/attachment.p...9&d=1193497932

HAILERS

Take note of how in my jpg the half of the plug that is RED is a part of the FRONT harness and the half of the plug that has no color is a part of the EM harness. They're also ID'd by having the lettes F next to the Red half and EM next to the clear colored half.

That LgB wire was a signal from the pwr steering to the ECU that the wheel had been turned. If you have no pwr steering it will have zip effect on your life.

keenangodburn

ok so eliminate the lg/B wire and leave y/w wire in the 15 pin conector and run a wire from that to the lg/b wires' location.
or remove both wires and plug y/w into the 13 pin connector leaving the plug in the 15 pin connector empty.

keenangodburn

scratch that ^
OH!!! take the y/w from the body harness side and plug it into lg/B (engine side) leaving the old location of y/w empty.

HAILERS

iF you can remove the YW wire from the 15 pin connector and physically move it to the 13pin connector, that will work. You would have to move the LgB wire from that 13pn connector (ON THE EM HALF OF THE PLUG) and install the moved Y/W wire to that location on the end.

Then when you mate both halves of the 13pin plug, you will have a YW mating with a YB wire and all will be fine and dandy.

I think you got the plugs wrong in your last post. You move the YW from the fifteen plug connector to the 13pni connector. Your removing the YW wire from the half of the plug (15pin) that is connected to the EM harness to the other plug (13pin)that is a part of the EM harness.

In that jpg I attached that had an arrow from (YW) to the (YB) was to demonstrate what the YW has to mate with. If possible and the wire is long enough, you want to remove the (YW) and install it in the EM half of that other plug where a (LgB) wire now exists.

In other words you just dealing with the CLEAR colored plugs in the jpg. When you mate them together you turn one plug 180* so the wire colors are the same when the plug is mated to each half. Get that??? Look at the plugs. See how the wire colors are just the opposite from each other. Like a (LgB will be on the left end of one plug and it's on the right end of the other half of thet plug. So when you mate therm you flip one half of the plug 190* to mate with the other half?????

HAILERS

NO ONE WILL EVER GET ME TO CALL THE em HARNESS THE engine HARNESS AND NOBODY WILL EVER GET ME TO CALL THE front HARNESS THE BODY HARNESS. NEVER EVER, EVER, EVER. some humor.

If everybody called the EM harness the EM harness and the Front harness the F harness, then we'd all get along and be able to look at the wiring schematic and not be talking Chinese or what did they call it??? Eubonics or sometbing like that. very slight humor in this post. very little, but some.

HAILERS

No, not really. Read the post I made as you wrote that one.

Your dealing ONLY with what YOU call the ENGINE HARNESS. Move the (YW) from the fifteen pin connector TO the thirteen pin connector.

You move it to the end of that 13pin connector where there is presently a LgB wire. The Lg/B gets removed and the YW gets put in that socket IF IT WILL REACH FROM THE 15 PIN PLUG TO THE 13PIN PLUG.

If it won't reach, then just get a short piece of NEW wire , and splice the (YW) to where the( LgB) is. You might leave that wire in the socket and cut the LgB wire a few inches back from the plug and splice your new wire to the piece of the LgB that was left in the plug.

Bottom line...........the YW wire in the EM harenss NEEDS to mate with the YB wire in the Front harness by hook or crook. Any way you want to do it. There's three or four ways to do it. But in the end the YW in the EM harness NEEDS to mate with the WB in the Front harness so the water temp gauge will work.

I'm writing this with the thought that a Turbo EM harness was put in a non turbo car and the FRONT harness is still a non turbo harness.

I've never done this myself. I just used my non turbo EM harness on the engine with minor changes to the EM harness. For ME it was easier. I NEVER remove the EM harness when removing an engine (well, I did that ONE time and one time only. Never again).