I did a bunch of these swaps and just ran across my old DIY for it. Figured I would help out a bit here for you old school EF civic guys (the few here).
Originally posted here
Ok I have been seeing a lot of posts about swaping to MPFI. Here it is made simple. This should only take you no more then 3 hours to accomplish for a do it your selfer.
Parts list:
All parts listed are from a 88-91 civic Si
Si MPFI intake manifold w/ all sensors, TB, injectors, and rail
Si engine harness
Si injector plugs
Si injector resistor box
Si distributor (d16a6)
Si throttle cable
PM6 ECU
a U-bend heater hose, if not on IM.
new intake gasket
Tools:
10mm wrench/ socket
12 mm wrench
pliers
cutting pliers
wire strippers
soldering gun
solder
heat shrink or electrical tape
screw drivers
wire
The engine bay is pretty much straight foward. Drain out the coolant first. Begin marking with plugs you remove from the IM. Be sure to dis conect all the sensors. I wrote the sensors name on a peice of tape attached to the wires. You can then atrt removing the vac. and coolant lines. Remove the fuel line and tuck it to the side. You can take the entire throttle cable out of the car, you will be using the shorter Si one instead.
At this point you should have everything on the manifold disconnected and ready to come off. Start taking the 12mm nuts off that removes the mani. from the head. Once off, scrape the old intake gasket off. Even though it may still look good to use. It’s better to replace it now rather then later.
Now it’s mostly doing the oppisite when installing the mpfi manifold. Dont worry about the wiring yet for the mani. Get all the vac. lines and coolant lines hooked back up. You will notice that you will need a U-bend heater hose to come off the head and go back to the mani. Install the new Si throttle cable.
You should have the intake completly on the motor no, except for the wiring.
Now remove the old distributor. You can cut of the two plugs that go to it from the harness. Using the Si engine harness find the two plugs for the dizzy (both should be round) and cut them off leaving enough wire to solder to. They should be a round style plug instead of the square std/dx ones. match up the wires and solder the plugs the the harness in the car. You will have 2 extra wires coming off the bigger plug. These will be used later on. Install the Si dizzy now.
You can mount the injector resistor box somewhere near the fuel rail. I put mine on the left shock tower.
The wiring is made a lot more simple here.
ECU plugs
At ECU
C1 ecu wire to B10 pin
C2 ecu wire to B12 pin
Run C1 pin to distr.
Run C2 pin to distr.
A3 ecu pin to engine bay and mark it
Same thing with the A7 ecu pin
Plug in the si’s PM6 ecu, in place of the dx pm5 one.
Engine Bay
DX/HF yellow injector wire to #1 injector(brown)
DX/HF Red injector wire to #3 injector(blue)
A3 to #2 injector (red)
A7 to #4 injector (yellow)
Connect all 4 red/black wires to the resistor box
Connect the Yel/Blk DX injector wires to the yel/blk one on the resistor box as well.
C1 to blue/green wire on distr. Becareful not mix these two up!
C2 to blue/ yellow wire on distr.
The Yellow and green wires on the TPS sensor need to be swapped around. The middle red wire stays where it is.
These plug wires will need to be extended: TPS, IAC, EVAC. There will be one plug that is not used on the MPFI intake that the DPFI had.