Akuma Trueno...I switched the whole harness so I wouldn't have to get into splicing two together. There is one plug that you have to cut and splice that comes out of the ecu and goes into the dash. Hey wait...I found this on another forum. Hope it helps.
Ka24E (SOHC) to Ka24DE (DOHC) F.A.Q.~
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I asked alot of questions, and so have others with no reall answers to how to do all this, I finally finished it, and Am gonna help out some others.
So here goes~~~
So you start with a 89-90 sohc 240
ANd you wanna install a more ready available doch motor,
What you need to do this::
any ka24de motor and tranny. The sohc tranny will work if you have dohc bell housing.
s13 dohc ecu
s13 dohc wiring harness,
s13 dohc distrib, and coil
s13 dohc tach
s13 dohc throttle cable
s13 dohc maf sensor.
s13 dohc exhaust manifold, and factory downpipe.
s13 dohc intake. manifold, must be used if using a 94+block
s13 dohc air intake
s13 dohc powersteering lines (if you want it)
s13 dohc cruise controll (if you want it)
Preping the car. First off remove old sohc motor,and Tranny, you can do this at the same time, as i did, just make sure you go inside and take off the plastic pieces and remove the shifter. And unbolt the driveshaft. Also remove all the other pieces such as powersteering.And remove the stock computer and wiring harness, This is by far the hardest part of the swap, because the wiring has this plastic L shaped thing taped to it under the dash, and you can NOT pull it thru the firewall, (i tried) so you have to reach up under there and cut it away,, Its really a pain in the ass. You also wanna go ahead and install the s13 dohc wiring harness at this time so you have more room under there to try to wiggle wires thru the hole. Dont plug the wires into the ecu yet because you have some wiring to do under the dash. Next Degrease everything, Grease suspension... what ever you wanna do.
Next prepping the dohc motor to install. You need to remove all the old sensors from the sohc tranny, and some other ones on the motor, to replace the dohc one if using post 93 motor and tranny. If your using pre 93 dohc motor, then all your sensors will work. If using a post 93 block you need to now install the s13 dohc intake manifolds. I used the 96 upper intake and 93 lower intake when i did my swap, just so i coulld remove the secondary butterfly set, that seemed to trap up some airflow. I also capped all the vacume lines at this time and blocked off the egr valve. ((only if you live in a good county)).
Ok now that you have the wiring harness in the car drape it over the fender out of the way, And install your motor. I took off the front bumper and headlights and hood when doing my install so i would have more ability to get under the hood of the car (the pignose sticks out FAR) The motor goes in pretty easy, I did it with the tranny still atached for simplicity of it all, and so i didnt have to lay under the car and attempt to install it by my self! Also make sure the shifter is out of the tranny, or your gonna tear it up!.
Once the motor is in, Its all cake. INstall the driveshaft, it just slips right in,and then bolt the thing together, Next Just plug up the harness to where each thing goes, its realy easy, no rewiring anything under the engine bay. if the distrib is still in and hasnt been knocked around then your car even may still be timed. HEHE. Your radiator hoses require a bit of tweaking, but they do work.
Next install your throttle cable, its simple, just two bolts under the dash, and its in and out. I think that the sohc would work, but it would be pulled tight across the top of the motor and would look pretty bad, with the s13 dohc one you can tuck it back out of the way, and it looks alot better.
Since your inside the car, install the shifter Its simple! make sure you top the tranny off with fluid. and walla.
The next and easiet thing of all to do is connect the wires under the dash, there are 6 wires that you will need to attach, and thats it, the rest go to a check connector, and are not required to get the car running::
Yellow/red --Tach
Yellow/Green--speedo
orange--ignition start
black---ground
blue/black---water temp sensor.
These are the same color wires on each harness, the only reason that you have to remove the connector, and cant use it is because the wires would not meet up in the same place, but its really easier than it may look.
Also you will need to remove the cluster from the dash and install the Tach, its only held in the back of the cluster by three screws. Its easy also.
Last is to bolt all the body parts on and fire it up, you should be ready to go, if it doesnt start then check for spark and then for fuel. This happend to me and i finally found out why, I didnt install a ground on the back of the motor, no big deal but it was kinda pissing me off.
If you have any questions just post them and ill answer asap. Or pm me. But Just remember guys Its always easier than it looks.
have fun!!
~Chris
[email protected]
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1987 mazda RX7 TII
1990 240 hatch
1983 k5 blazer
Need a good set of drifting wheels for the nissan, if you have any pm me!