Parts for DPFI to MPFI swap (can be sourced from a 4 gen Civic/CRX Si )
Complete Intake (For best results get a SOHC VTEC Intake Manifold from a D16Z6 or D16Y8 and put a B series Throttle Body on it)
Injector Resistor 
ECU
Distributor 
Si coolant hose to connect the manifold and the block u can use your stock and cut it if you are cheap

Its pretty easy you'll want to drain the radiator and all then take off the intake manifold and put the Si intake manifold on and rewire everything. disconnect all the plugs from all the sensors and the injectors make sure u disconnect the coolant lines from the intake and there is one bolt that holds the manifold to the block underneath u wont see it unless u know about it 

In order to convert your dual point injection DX to multi-point injection you will need 4 injector plugs, an injector resistor box, extra wire, and electrical tape (heat shrink is best). Also, when doing this conversion I would highly recommend soldering all connections and heat shrinking them. It is good to have an extra multi-point injection engine harness laying around to take plugs off of (injector plugs, injector resistor box plug, and distributor plug u can use your stock dist plug if u cut one off another DX dist and use it to plug in but your need a 2 wire plug for the ca sensor). 

Pins B10 and B12 are empty. Unused pins can be taken from B2 or B11. Sometimes there is a unused wire at B12. 
Cut orange and white wires off at C1 and C2 and connect them to wires added at B10 and B12. Orange-B10. White-B12. Leave enough wire for next step. 

Run wires from C1 and C2 on the ECU into the engine compartment. Label these wires for later use. 
Cut wires at A3 and A7 leave excess for later use. Run these wires into the engine bay and label them to be used later on . 


Under the Hood 

TPS and EACV plugs are too short and must be extended. 
Be sure to switch green/white and yellow/white wires on TPS since the DX turns the opposite way.


Injectors and injector resistor box 

Connect the yellow/black wires from the two DX injector harnesses and run it to the yellow/black wire on the injector resistor box. 
Connect the yellow wire from the DX injector to the #1 injector (brown wire). 
Connect the red wire from the DX injector and run it to the #3 injector (blue wire). 
Connect the A3 wire to the #2 injector (red wire). 
Connect the A7 wire to the #4 injector (yellow wire). 
Connect the 4 red/black wires from injector resistor box to each injector. 

Cylinder position sensor 

Connect C1 to blue/green wire on cylinder position sensor plug. 
Connect C2 to blue/yellow wire on cylinder position sensor plug
the rest of the wires are color matched your DX to the Si wires

I think that's it let me know if I forgot anything
_______

STD OWNS YOU ALL

88 std hatch
86 CRX Si (mini shitter2)

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Another online How To can be found here.