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OBD0 88-91 Prelude to OBD1 ECU Jumper Harness Installation Instructions

Please be careful when installing this harness. There are 10 wires that need to be connected for proper usage. Incorrect installation may cause damage to your vehicle and/or engine computer.

If there are certain sensors that your engine or ECU does not require, just tape off that wire and leave it unhooked. You will need to have a STOCK wire harness where it plugs into the ECU. No added VTEC wires, etc. - STOCK. You will connect all of the new wires later. So after you have a completely stock harness, plug the ECU jumper into the stock ECU harness plugs and lets go:

Parts List:

  • OBD0 Prelude to OBD1 ECU jumper harness.
  • OBD1 or OBD2 distributor that fits onto your engine.
  • OBD1 ECU
  • OBD1 or OBD2 injectors and injector clips (optional - you can use the stock injectors with the stock injector resistor box).
  • 4-wire O2 sensor (optional - if you are using a chipped/programmable OBD1 ECU with O2 sensor disabled you do not need to wire in a 4-wire O2 sensor)

1. Connect the BROWN wire to one of the black wires on the 4-wire O2 sensor (O2 heater control).

2. Connect the PURPLE wire to the green wire on the 4-wire O2 sensor (O2 ground).

3. Connect the YELLOW wire to one of the black wires on the 4-wire O2 sensor (O2 12v switch).

4. Connect the GREY wire to the white wire on the 4-wire O2 sensor (O2 signal).

Due to the number of different O2 sensor wire colors with aftermarket O2 sensors, these may vary, and you may need to try moving these. The colors listed in steps 1-4 should match the OEM Honda/Acura OBD1 civic and integra O2 sensors.

5. Connect the BLACK wire to the VTEC solenoid.

6. Connect the GREEN wire to the VTEC pressure switch. The VTEC pressure switch is located below the VTEC solenoid. Connect the GREEN wire on the conversion harness to the blue wire on the VTEC pressure switch connector. The other wire on the VTEC pressure switch connector should be connected to ground (recommended to connect to ground on thermostat housing).

7. Connect the WHITE wire to the knock sensor located on the back of the engine block. If your engine does not have a knock sensor, simply tape off this wire and leave it unhooked.

8. If you are using a GSR or H22 intake manifold and ECU with IAB control (ie: P72, P13), you can connect the RED wire to the pink/blue IAB wire of the IAB solenoid connector. The black/yellow wire from the IAB solenoid connector needs to be wired to a switched 12v power source. If you are not using IAB's, simply tape off this wire and leave it unhooked.

9. The remaining blue wire and orange wire can be used to check engine light codes. Simply connect a toggle switch between the blue wire and orange wire, then toggle the switch to flash check engine light codes on your dash.

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