The truth about a n/a to turbo swap in the 86 to 88's
 

Every one seems to think that you can just take
a TII motor with all its wiring etc, and plug it into a
non turbo car and go.
this is not true!
Its close, and you might be able to get it to run,
but there are a few wiring changes that need to be
made to the TII's motor wiring harness.

I am in the process of putting a TII motor and all its
wiring into a vert. all the plugs look like they would just
plug together but after looking at the connections and
differences between the turbo and n/a I see that there
is no alt. wire in the TII harness, these need to be
added, there is no wire going from the knock box to the
main computer, this needs to be added.
a relay needs to be added to the power steering switch
and the wire that came from the power steering switch
to the main computer has to be cut off added to this
really and in its place the wire from the knock box has
to go where you cut the ps switch from.
I hope to have all my notes done up to explain what I
have found.
if anyone needs help with these problems pm me and I
will try to help..
matt

Another peark of a standalone EMS. No shitty old harness to deal with or try to rewire etc.

this is true but adds to the cost just a little.

matt

Re: The truth about a n/a to turbo swap in the 86 to 88's
 

There are a couple of pins that need to be moved if you are not using the T2 harness as well.

hasen't this been covered before???

I AM using the TII harness.
There is much more than a couple pins that need to be moved.
I did a search and found nothing about this topic, and
the sites and other people who have done this swap didn't
seem to know anything about what was missing.

matt

the answer is DFI.

SO all the other people on this board and elsewere who have done this swap without adding relays and pinouts are in the wrong huh? I suppose those conversion cars that are still out there running around are just flukes or hacked up pieces of garbage with critical systems missing or inoperative, huh? :rolleyes:

Kevin, what do you do about the alternator plug then?

What the hell happened to the sticky on NA -> TII conversion? Mods? I thought that was a good thing to have right at the top of the 2G forum.

I am sure that the swap could be done without doing it right
and it would work, but I am sure that the knock box should
be connected to the computer,, for whatever reason it
was connected by mazda.
I am not trying to pi$$ on anyone else's efforts but
lets get it right!
matt

The NA to TII swap is very straightforward if you do it the "proper" way. This means swapping the whole drivetrain and the following harnesses:

-engine bay
-ECU
-dash and related

Not hard at all. You only run into problems when you decide to mix and match the TII and NA parts.

This swap has been done thousands of times, you are not doing anything special nor unique.

THank you. Im glad to see that Im not the only one.

You only rewire stuff if you use an NA harness. You should use a t2 harness, as stated on my webpage.

THe plug on the alternator is just like the plug on any other alternator in any other vehicle...its for internal voltage regulator. You really only have to supply one of the terminals with voltage, which loads the alternator and gets it started charging. So, jumper a wire right off the main terminal over to the small one and plug it in. I had to figure out the same thing on my s-10 blazer with a 350 v8 swap...the plugs were different, so I just figured out which terminal needed juice, and jumped a wire from the main terminal over. I once had a s-10 with a loud stereo that I put on 2 alternators with 2 batteries to support it...same thing there with those 2. You dont think I rewired the whole truck for just the alternators do you?

The swap is not very much harder than replacing a bad NA engine with an other NA. The only issues I have run into are, high impeed injectors vs. low impeed, and the missing alternator plug.

Kevin could you make a "diagram" of what you said? I am a visual person and have a hard time understanding your write up. we won't laugh;)

yes injector differences are a factor, but if this is all
you are worried about when putting a TII motor with its harness,
into a n/a car with the n/a's car side wiring harness,
you will be missing a couple things.
matt

quote:"
You only rewire stuff if you use an NA harness.
You should use a TII harness, as stated on my webpage"

you say to use the TII harness, this is what I did.
I did not change the car side wiring. I looked at your informative
and appreciated web page, you say nothing about
having to change the car side harness, unless you are putting
in a motor from another year / series.
I have a 88 vert, and am putting in a 87 TII motor with
its wiring harness.

Aaron Cake> yes I know that the best way to do this job
would have been to change the car side wiring with the
motor etc, but from what everyone says, you don't need to.
as for the alt plug if you change the car side wiring harness it would be there.
if not, it can be easily added to plug x-15 where the two
wires connect to the boost gauge in the TII harness, just
cut them off , tape them up and connect up a home made
length with the plug on it.

"This swap has been done thousands of times, you are not doing anything special nor unique.
"
I realize that I am not doing anything unique here, other than connecting up
the TII harness to the n/a harness properly. which on one seems interested in
doing.

matt

Is this a Jspec or USspec swap??? because there are no strange wire arounds...

Maybe because you are using the wrong year engine harness to the car (should be an 88 harness and injectors into an 88 vert), or you think you are using a T2 harness when you are really using a NA harness???

In the 87 and the 88 T2, the knock box wires and sensor plugs are part of the engine harness... so again I am wondering what the deal is that you were not able to find them, if you really had a t2 harness.

icemark> yes the TII motor just came out of a Canadian
1987 TII, going into a Canadian vert 1988.
yes the knock box, and its plug are in fact on the motor
harness, but if you look in at the wiring diagrams in the
shop manual, it clearly shows the differences between
the TII wiring, and the n/a wiring.
If you look at the common connector page at the back
of the wiring area of the manual it shows all the
common "x" connectors.
the TII motor harness has two plugs that plug to the
computer, one for a pressure sensor, one
for the knock box, and two more big flat ones,
these two are listed in the common "x" connectors part of the
manual as x-15 and x-16,
its in these two plugs where the alt wirings have to be added
to the TII harness, along with the
water temp sender wire which needs to be
moved from x-15 to x-16, also if you look
the light green wire that runs from the knock box plug to the
computer, it runs through x-16 which on the n/a car side
has no connection at all, if you do not add a wire to the
car side of the n/a harness, I am unsure as to how,
whatever it is that the knock box sends to the computer is
going to get there.
I will post a picture of the changes between the two as soon as
I get the car done and when I make a clean set of notes.


Matt

You guys make it all so complicated.... i just plugged everything into my S4 NA harness for the S5 T2 motor and it ran fine.

jahoo88> hope you changed the oil metering pump as
well.

matt

now-thanks for the writeup on the alternator plug, I'll figure that out tomarow. By shop manuals do you mean the FSM, or Haynes?

Jahoo88-If I remember corectly you are using an S5 AFM on your car? If so how did you rewire the s4 harness to accept it?

In case this wasn't apparent, the 88 engine harness is wired much closer to the S5 cars than to the S4 cars. Crossingbreeding harnesses will result in the confusion you are finding.

But again from your reply it appears that you are using a NA harness which will require re-wiring or a incompatible year engine harness.

You said and now you say they are? Anyway the lightGrn wire, from the knock computer (by the way) connects to pin R of the first plug at the ECU. This is the same wire as used by the 86-87 NA ECU to sense the power steering feed. On the 88 NA cars the wire color is Grn/Blu, but again connects to the steering sensor, rather than the knock computer which is only found on the T2 versions. The 88 also does not run that wire through the X16 or X15 connectors.

So again...

You will either be required to re-wire or use the correct harness for the correct year. Pretty cut and dry.

Icemark> correct, the knock computer connects to pin R
of the first plug at the ECU.
this green wire runs through x-16 on the TII motor
harness from the knock box, but like you said the
86-87 NA ECU this wire is to sense the power steering feed,
this needs to be changed when connecting the TII motor harness
to the n/a car side harness.
Look at x-16 on a n/a car where the Lg wire is on the TII
there is nothing there in the n/a car plug.
So what I have been saying is that if you are doing
this swap mixing a TII motor harness to a n/a car
side harness these changes have to be made.
no one seems to list these changes, rather they just
say it plugs right in and works which is wrong!

Matt

I just took the OMP off and ran premix. It is the S4 T2 afm that im using.

what do you guys mean by car side harness and motor harness?

Well I tell you what. WHy dont *YOU* do a big writeup for all of us non-knowing dumbfucks and inform us of the error of our ways. Do a big search on the forum and find all the people who have done these swaps long before you, and tell them what they need to go back and rewire to finish their running/driving conversions the *right way*, so that you can sleep at night.

Shit, try to help people and this is the attitude you get. Im ready to take what technical information I have posted up (not for my own health, but for the good of others who might like to know) down off my page and saying "fuck it, there are others out there who know more about an rx-7 than probably even the man who designed them, so why should I bother?". Let the newbies and the people who are doing this stuff fend for themselves. Now you'll get to see a lot more of this:



https://www.rx7club.com/forum/attach...postid=1352915

No, again you ar incorrect. At most sites that list the swap, they recommend swaping the dash harness and in most cases front harness as well.

I think you didn't search correctly.. and again the majority of the problems you have had are related to the wrong year engine harness for the cars body (have I yet made it clear and do you understand the 88 in both T2 and NA form was different than any other year??? and not a straight swap with an 87. Think of an 88 as series 4.5 rather than series 4 if that helps).