Quote:
Originally Posted by kermit
I'm assuming that you would somehow have to graft in the vx ecu...
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Right. You could run it off of other ECUs, but they wouldn't take full advantage of the engine's abilities.
There are adapter harnesses around to go from OBD-0 ('88-91 CRX) to OBD-1 ('92-95 Civic), but I'm not sure they cover the additional ECU connections used by the VX. If soldering doesn't bother you, you could cut off the HF's original ECU connectors and attach the VX's... That's what I did with my 'Z6 swap.
It would be easiest to start with an HF, since it already has MPFI and EGR wiring, as well as the EGR hardware on the firewall. An Si has the MPFI wiring, but not EGR, and a DX has neither (unless you have a CA emissions DX auto - it has EGR but not MPFI).
Converting to MPFI requires running 4 wires from the ECU to the engine bay (two to the distributor and two for the additional fuel injectors) and a bit of re-wiring in the engine bay itself. If you were strictly converting a DX to MPFI, you would need a new distributor and intake manifold, but the distributor gets replaced anyway when converting to OBD-1, and the intake manifold should be included with your motor. OBD-0 MPFI injectors require a resistor box, but Honda did away with that in the switch to OBD-1, so no need to worry about it.
Setting up the EGR wiring would require running 2 more wires from the ECU to the engine bay. One for the EGR control solenoid on the firewall, the second for the EGR lift sensor on the engine. The sensor also needs 5V power and sensor ground, but those can already be found in the engine wiring harness, so you just need to tap into them.
As for VX-specific stuff, you need two new wires for the VTEC solenoid and pressure switch, and four (in addition to the existing one) for the wide-band oxygen sensor. If you go with the CA emissions setup with a simple heated oxygen sensor, you only need 1 additional wire.
Dalez0r 
Hybrid Mode
