Honda Civic/CRX D15B1/D15B2 MPFI Swap

The MPFI swap is one of the best ways to gain more performance out of a Honda D15B1 or D15B2. The stock DPFI system is a true bottleneck for the engine due to the small diameter of the throttle body and the poor flow rate of the injectors. Another downfall is that the DPFI ECU's have not been cracked, so they cannot be tuned. Any modifications done to the engine (ex. cold air intake/exhaust) will be useless with DPFI, and any gains in power will be minimal at most.

This tutorial is geared towards OBD-0 setups. OBD-1 conversions will not be covered here.


Parts Required:

1. A complete intake manifold from an MPFI Engine. I recommend the D16Z6, but the D16A6, D16Y8, and D15B7 can also be used.

2. MPFI ECU. You will need a pm6, pr4, or pg7 (note: will run rich with pr4 and pg7). Make sure you replace the OBD-1 injectors with OBD-0 injectors if using a D16Z6, D16Y8, or D15B7 intake manifold.

3. MPFI Distributor TD-02. The stock DPFI TD-01 distributor will not work.

4. Resistor Box: This can be pulled from a Civic/CRX Si

5. Four MPFI injector plugs, 7 pin Si distributor plug, resistor box plug.

6. New intake manifold gasket

7. Si throttle cable. (Not absolutely necessary, but it is much better over the long DPFI cable)

I highly recommend soldering and heatshrink wrapping ALL connections.


The best place I have found to start is at the ECU.

Here is a pin-out diagram for the MPFI OBD-0 ECU:

Inside car at the ECU plug:

1. Pins B10 and B12 are empty. Unused pins can be taken from B2 or B11. Some models have a wire located at B12.
2. 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.
3. Run wires from C1 and C2 (direct ECU connection) into the engine compartment. Label these wires for later use.
4. Cut wires at A3 and A7 leaving plenty of wire. Run these wires into the engine compartment and label them for later use.


Next move on to the engine bay:

1. TPS and EACV plugs are too short and must be extended.
2. Be sure to switch green/white and yellow/white wires on TPS. If you do not do this, it will read WOT when the throttle is closed.

Injectors and injector resistor box:

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

Distributor Cylinder position sensor:
1. Connect C1 to blue/green wire on cylinder position sensor plug.
2. Connect C2 to blue/yellow wire on cylinder position sensor plug.


That's about it, the swap is fairly straightforward. Fire it up! Check the ecu for codes, and do whatever idle adjusting is needed. Good luck to you!