Electrical

2 compatibility entries for Honda

Engine management (OBD0 to OBD1 conversion) Verified Modification Required

OBD1 ECU (P75) and OBD1 distributor with OBD0-to-OBD1 conversion harness

Source: Integra VTi-R (DC2 (OBD1 era))
Target: CR-X SiR (EF8 (OBD0; procedure applies to any OBD0 Civic/CR-X)) - 1989-1991

Documented conversion of an OBD0 EF8 CR-X to OBD1 using a P75 ECU and an OBD1 distributor from an Integra VTi-R; a DC2 distributor bolted up and worked well. The car ran Crome with a stock 203 ROM for an OBD1 JDM B16A and started on the first attempt. The original single-wire O2 sensor works fine with the heater circuits disabled in the ROM. With this harness the blue 2-pin connector formerly used for setting timing (under the LH dash near the heater blower on EF8/EF9) becomes the SCS connector for OBD1 diagnostics and base-timing adjustment. Base ignition timing must be set with a timing light after conversion. A follow-up member completed the same conversion successfully with the car starting first go.

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Ignition and starting system Verified Modification Required

S2000 engine start button

Source: S2000 (AP1)
Target: Prelude (5th generation) - 1997

Working conversion documented on a 1997 (5th-gen) Prelude. The key barrel, steering lock and factory immobilizer are retained; the key is turned to ON and the button is pressed and held to crank, exactly replicating S2000 operation. The relay schematic transfers to any Honda - a follow-up contributor fitted a JDM Civic Type R start button and panel to a Civic FD as a direct bolt-in using the same diagram (adding pin 1 illumination negative and pin 2 illumination positive), and another contributor wired a button on a DC2 with a simple two-wire hookup at the ignition barrel loom (constant 12 V plus starter wire). With the ignition on, the ENGINE START legend illuminates without the parking lights on; this matches factory S2000 behavior.

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