K-series engine (K20/K20A2) swap conversion wiring harness

K-series engine (K20/K20A2) swap conversion wiring harness

Engine Conversion wiring harness Verified Modification Required

Compatibility Overview

Source Vehicle

RSX Type-S

Generation: DC5

Years: 2002-2004

Target Vehicle

Civic

Generation: EG

Years: 1992-1995

Installation Difficulty

Easy Basic tools
Moderate Some experience
Difficult Skilled work
Expert Professional

Reference

K20A specs → D14A1 specs → K20Z4 specs → LEA-MF6 specs → LEA specs → K20Z2 specs → B18A1 specs → K20Z3 specs → K20A3 specs → D16A6 specs → B18B1 specs → K20Z1 specs → K20A2 specs → A16A1 specs → B18C2 specs → B18C7 specs → D16A8 specs → D16W4 specs → EA specs → EC specs → ED specs → EE specs → EF specs → EG specs → EK specs → EL specs → EM specs → EN specs → EP specs → ER specs → ES specs → ET specs → K20A1 specs → K20A4 specs → K20A6 specs → K20A7 specs → K20A9 specs → K20B specs → K20Z5 specs → LEA2 specs → PPA Cylinder Head → PRB-A00 Cylinder Head → RNE ECU → RPM ECU → PPA ECU → PPA →
The RSX C101 connector mates to the K-series engine harness and the E-plug feeds the K-series ECU. The EG's original main relay is removed and its socket reused as a junction for the fuel-pump and ignition taps. Core circuits land in the stock B-series ECU connector: fuel pump (A7), ignition (A25), battery positive (D1, on a 30 A fuse), ELD (D10), brake switch (D22), MIL (A13), FanC (A12), and Alt-L (A16). VSS, RPM, and oil-pressure signals go to the cluster/gauges, with VSS tappable directly from the instrument cluster. The secondary O2 sensor and DLC are added separately from the service manual. Builders report clean, CEL-free startups once all connections are verified. The same method has been adapted to EF/CRX, EK, and DC2 chassis, which use different main relays and cluster signals.
This documents the electrical integration for a K-series swap into an EG chassis, which requires a custom-fabricated conversion harness rather than any bolt-in part. Salvage the C101 and E-plug connectors from an RSX sub-harness (a 2002 Civic sub-harness also works but is missing some circuits that must be added). Wire in three relays per the Hondata schematic. Delete the factory main relay and repurpose its socket by bridging terminals 7-8 (fuel pump to ECU A7) and 3-5 (ignition to ECU A25). Upgrade the underhood battery-feed fuse from 7.5 A to 30 A. Because the Hondata schematic omits the secondary O2 sensor and the DLC, wire both from the factory service manual. The fuel-pump ground pin must be moved between E1 (USDM PRB ECU) and E10 (JDM PRC ECU) depending on which ECU you run.

Important Caveats

  • • Confirm your ECU before wiring: a USDM RSX-S PRB grounds the fuel-pump relay at E1, a JDM Type R PRC at E10 - the pin must be relocated accordingly.
  • • The MIL (E31) and fuel pump (E-plug pin 1) may already connect through the retained B-series plug; do not double-wire them.
  • • Adaptations to EF/CRX and EK chassis differ (different main relay, cluster VSS source) and are frequently reported as untested - verify against your own chassis.
  • • Check every connection with a multimeter before first start; a mis-pinned wire can throw a VBU code or damage the ECU/K-Pro.

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Community Verification

1
user verified this swap
By kazino42 via K20A.org
Added 2 days ago

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