Miata NA8 → K-CI v1 (chassis adapter)
Drawn by Michael Gnankou · Rev 0 · proposal · 2026-10-04
Revisions
| Rev | Label | By | Date |
|---|---|---|---|
| No revisions yet. | |||
Schematic
Connectors
KCI
Mating face
Wire side
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | C1 | — | 0.5 | PCM-1-A | — | — | — |
| 2 | — | — | C2 | — | 0.5 | PCM-1-B | — | — | — |
| 3 | — | — | C3 | — | 0.5 | PCM-1-C | — | — | — |
| 4 | — | — | C4 | — | 0.5 | PCM-2-A | — | — | — |
| 5 | — | — | C5 | — | 0.5 | PCM-2-B | — | — | — |
| 6 | — | — | C6 | — | 0.5 | PCM-2-I | — | — | — |
| 7 | — | — | C7 | — | 0.5 | PCM-1-E | — | — | — |
| 8 | — | — | — | — | — | — | — | — | — |
| 9 | — | — | — | — | — | — | — | — | — |
| 10 | — | — | — | — | — | — | — | — | — |
| 11 | — | — | C8 | — | 0.5 | PCM-1-R | — | — | — |
| 12 | — | — | C9 | — | 0.5 | PCM-2-T | — | — | — |
| 13 | — | — | C10 | — | 0.5 | PCM-1-J | — | — | — |
| 14 | — | — | C11 | — | 0.5 | PCM-1-Q | — | — | — |
| 15 | — | — | — | — | — | — | — | — | — |
| 16 | — | — | C12 | — | 0.5 | PCM-1-V | — | — | — |
| 17 | — | — | — | — | — | — | — | — | — |
| 18 | — | — | C13 | — | 0.5 | PCM-1-M | — | — | — |
| 19 | — | — | — | — | — | — | — | — | — |
| 20 | — | — | — | — | — | — | — | — | — |
| 21 | — | — | — | — | — | — | — | — | — |
| 22 | — | — | — | — | — | — | — | — | — |
| 23 | — | — | — | — | — | — | — | — | — |
| 24 | — | — | — | — | — | — | — | — | — |
| 25 | — | — | — | — | — | — | — | — | — |
| 26 | — | — | — | — | — | — | — | — | — |
| 27 | — | — | — | — | — | — | — | — | — |
| 28 | — | — | — | — | — | — | — | — | — |
PCM-1
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| A | Constant +12V | — | C1 | — | 0.5 | KCI-1 | — | — | — |
| B | ECU power +14V (main relay) | — | C2 | — | 0.5 | KCI-2 | — | — | — |
| C | Start signal | — | C3 | — | 0.5 | KCI-3 | — | — | — |
| E | Malfunction indicator lamp (MIL) | — | C7 | — | 0.5 | KCI-7 | — | — | — |
| G | Ignition 1 (coils 1+4, wasted spark) | — | — | — | — | — | — | — | — |
| H | Ignition 2 (coils 2+3, wasted spark) | — | — | — | — | — | — | — | — |
| J | A/C relay | — | C10 | — | 0.5 | KCI-13 | — | — | — |
| M | Vehicle speed | — | C13 | — | 0.5 | KCI-18 | — | — | — |
| P | Power steering pressure switch | — | — | — | — | — | — | — | — |
| Q | A/C request | — | C11 | — | 0.5 | KCI-14 | — | — | — |
| R | Cooling fan relay | — | C8 | — | 0.5 | KCI-11 | — | — | — |
| V | Neutral/clutch switch | — | C12 | — | 0.5 | KCI-16 | — | — | — |
PCM-2
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| A | Power ground | — | C4 | — | 0.5 | KCI-4 | — | — | — |
| B | Power ground | — | C5 | — | 0.5 | KCI-5 | — | — | — |
| C | Power ground | — | — | — | — | — | — | — | — |
| D | Power ground | — | — | — | — | — | — | — | — |
| E | Crank position (CAS NE) | — | — | — | — | — | — | — | — |
| F | MAF ground | — | — | — | — | — | — | — | — |
| G | Cam position (CAS G) | — | — | — | — | — | — | — | — |
| I | Tachometer output | — | C6 | — | 0.5 | KCI-6 | — | — | — |
| K | +5V sensor supply | — | — | — | — | — | — | — | — |
| M | Throttle position (TPS) | — | — | — | — | — | — | — | — |
| N | O2 sensor | — | — | — | — | — | — | — | — |
| O | Mass air flow (MAF) | — | — | — | — | — | — | — | — |
| P | Intake air temperature (IAT) | — | — | — | — | — | — | — | — |
| Q | Coolant temperature (ECT) | — | — | — | — | — | — | — | — |
| R | PRC solenoid (fuel pressure regulator) | — | — | — | — | — | — | — | — |
| S | Condenser fan relay | — | — | — | — | — | — | — | — |
| T | Fuel pump relay | — | C9 | — | 0.5 | KCI-12 | — | — | — |
| U | Injector 1 | — | — | — | — | — | — | — | — |
| V | Injector 2 | — | — | — | — | — | — | — | — |
| W | ISC solenoid | — | — | — | — | — | — | — | — |
| X | Evap purge solenoid | — | — | — | — | — | — | — | — |
| Y | Injector 3 | — | — | — | — | — | — | — | — |
| Z | Injector 4 | — | — | — | — | — | — | — | — |
Pin map
| OEM point | OEM function | OEM family | Target point | Target function | Target family | Wire colour | Evidence |
|---|---|---|---|---|---|---|---|
| PCM-1-A | Constant +12V | power_in | — | — | — | single_source | |
| PCM-1-B | ECU power +14V (main relay) | power_in | — | — | — | single_source | |
| PCM-1-C | Start signal | digital_in | — | — | — | single_source | |
| PCM-1-E | Malfunction indicator lamp (MIL) | low_side_out | — | — | — | single_source | |
| PCM-1-G | Ignition 1 (coils 1+4, wasted spark) | ignition_out | — | — | — | single_source | |
| PCM-1-H | Ignition 2 (coils 2+3, wasted spark) | ignition_out | — | — | — | single_source | |
| PCM-1-J | A/C relay | low_side_out | — | — | — | single_source | |
| PCM-1-M | Vehicle speed | digital_in | — | — | — | single_source | |
| PCM-1-P | Power steering pressure switch | digital_in | — | — | — | single_source | |
| PCM-1-Q | A/C request | digital_in | — | — | — | single_source | |
| PCM-1-R | Cooling fan relay | low_side_out | — | — | — | single_source | |
| PCM-1-V | Neutral/clutch switch | digital_in | — | — | — | single_source | |
| PCM-2-A | Power ground | ground | — | — | — | single_source | |
| PCM-2-B | Power ground | ground | — | — | — | single_source | |
| PCM-2-C | Power ground | ground | — | — | — | single_source | |
| PCM-2-D | Power ground | ground | — | — | — | single_source | |
| PCM-2-E | Crank position (CAS NE) | trigger_in | — | — | — | single_source | |
| PCM-2-F | MAF ground | sensor_ground | — | — | — | single_source | |
| PCM-2-G | Cam position (CAS G) | trigger_in | — | — | — | single_source | |
| PCM-2-I | Tachometer output | tacho_out | — | — | — | single_source | |
| PCM-2-K | +5V sensor supply | vref | — | — | — | single_source | |
| PCM-2-M | Throttle position (TPS) | analog_in | — | — | — | single_source | |
| PCM-2-N | O2 sensor | lambda_nb_in | — | — | — | single_source | |
| PCM-2-O | Mass air flow (MAF) | analog_in | — | — | — | single_source | |
| PCM-2-P | Intake air temperature (IAT) | temp_in | — | — | — | single_source | |
| PCM-2-Q | Coolant temperature (ECT) | temp_in | — | — | — | single_source | |
| PCM-2-R | PRC solenoid (fuel pressure regulator) | low_side_out | — | — | — | single_source | |
| PCM-2-S | Condenser fan relay | low_side_out | — | — | — | single_source | |
| PCM-2-T | Fuel pump relay | low_side_out | — | — | — | single_source | |
| PCM-2-U | Injector 1 | injector_out | — | — | — | single_source | |
| PCM-2-V | Injector 2 | injector_out | — | — | — | single_source | |
| PCM-2-W | ISC solenoid | low_side_out | — | — | — | single_source | |
| PCM-2-X | Evap purge solenoid | low_side_out | — | — | — | single_source | |
| PCM-2-Y | Injector 3 | injector_out | — | — | — | single_source | |
| PCM-2-Z | Injector 4 | injector_out | — | — | — | single_source |
Cut list
| Wire | From | To | Gauge (mm²) | Colour | Length | Signal | Ident |
|---|---|---|---|---|---|---|---|
| C1 | KCI-1 | PCM-1-A | 0.5 | no route | Constant +12V | — | |
| C2 | KCI-2 | PCM-1-B | 0.5 | no route | ECU power +14V (main relay) | — | |
| C3 | KCI-3 | PCM-1-C | 0.5 | no route | Start signal | — | |
| C4 | KCI-4 | PCM-2-A | 0.5 | no route | Power ground | — | |
| C5 | KCI-5 | PCM-2-B | 0.5 | no route | Power ground | — | |
| C6 | KCI-6 | PCM-2-I | 0.5 | no route | Tachometer output | — | |
| C7 | KCI-7 | PCM-1-E | 0.5 | no route | Malfunction indicator lamp (MIL) | — | |
| C8 | KCI-11 | PCM-1-R | 0.5 | no route | Cooling fan relay | — | |
| C9 | KCI-12 | PCM-2-T | 0.5 | no route | Fuel pump relay | — | |
| C10 | KCI-13 | PCM-1-J | 0.5 | no route | A/C relay | — | |
| C11 | KCI-14 | PCM-1-Q | 0.5 | no route | A/C request | — | |
| C12 | KCI-16 | PCM-1-V | 0.5 | no route | Neutral/clutch switch | — | |
| C13 | KCI-18 | PCM-1-M | 0.5 | no route | Vehicle speed | — |
Bill of materials
| Category | Part number | Manufacturer | Description | Qty | Unit |
|---|---|---|---|---|---|
| connector | K-CI-01 | hx | K-swap chassis interface, 28-way (app-defined; physical part TBD per D2) | 1.000 | ea |
ECU setup sheet
| Role | Engine ref | Engine signal | Sensor | ECU point | ECU function | ECU class | Setup flag |
|---|---|---|---|---|---|---|---|
| No configured channels. | |||||||
Findings
Open (0)
| Severity | Code | Subject | Message |
|---|
Accepted (19)
| Code | Subject | Reason | By |
|---|---|---|---|
| REQUIRED_UNMAPPED | PCM-1-A | Wired through K-CI to the engine harness (seed 0039), which holds the aftermarket ECU; hx.validate() scopes nets to one harness, so the cross-harness reach is verified in the engine harness, not here. | mapping-proposal |
| REQUIRED_UNMAPPED | PCM-1-B | Wired through K-CI to the engine harness (seed 0039), which holds the aftermarket ECU; hx.validate() scopes nets to one harness, so the cross-harness reach is verified in the engine harness, not here. | mapping-proposal |
| REQUIRED_UNMAPPED | PCM-1-G | BP-ZE engine removed in the K24/K20 swap; this function is wired directly from the K-series engine layer (seed 0039), so the Miata PCM engine pin is intentionally dead. | mapping-proposal |
| REQUIRED_UNMAPPED | PCM-1-H | BP-ZE engine removed in the K24/K20 swap; this function is wired directly from the K-series engine layer (seed 0039), so the Miata PCM engine pin is intentionally dead. | mapping-proposal |
| REQUIRED_UNMAPPED | PCM-2-A | Wired through K-CI to the engine harness (seed 0039), which holds the aftermarket ECU; hx.validate() scopes nets to one harness, so the cross-harness reach is verified in the engine harness, not here. | mapping-proposal |
| REQUIRED_UNMAPPED | PCM-2-B | Wired through K-CI to the engine harness (seed 0039), which holds the aftermarket ECU; hx.validate() scopes nets to one harness, so the cross-harness reach is verified in the engine harness, not here. | mapping-proposal |
| REQUIRED_UNMAPPED | PCM-2-C | NA8 has four power grounds; the K-CI v1 interface carries two main grounds (gnd1/gnd2), so this one returns at the chassis rather than through the adapter. | mapping-proposal |
| REQUIRED_UNMAPPED | PCM-2-D | NA8 has four power grounds; the K-CI v1 interface carries two main grounds (gnd1/gnd2), so this one returns at the chassis rather than through the adapter. | mapping-proposal |
| REQUIRED_UNMAPPED | PCM-2-E | BP-ZE engine removed in the K24/K20 swap; this function is wired directly from the K-series engine layer (seed 0039), so the Miata PCM engine pin is intentionally dead. | mapping-proposal |
| REQUIRED_UNMAPPED | PCM-2-G | BP-ZE engine removed in the K24/K20 swap; this function is wired directly from the K-series engine layer (seed 0039), so the Miata PCM engine pin is intentionally dead. | mapping-proposal |
| REQUIRED_UNMAPPED | PCM-2-K | BP-ZE engine removed in the K24/K20 swap; this function is wired directly from the K-series engine layer (seed 0039), so the Miata PCM engine pin is intentionally dead. | mapping-proposal |
| REQUIRED_UNMAPPED | PCM-2-M | BP-ZE engine removed in the K24/K20 swap; this function is wired directly from the K-series engine layer (seed 0039), so the Miata PCM engine pin is intentionally dead. | mapping-proposal |
| REQUIRED_UNMAPPED | PCM-2-O | BP-ZE engine removed in the K24/K20 swap; this function is wired directly from the K-series engine layer (seed 0039), so the Miata PCM engine pin is intentionally dead. | mapping-proposal |
| REQUIRED_UNMAPPED | PCM-2-Q | BP-ZE engine removed in the K24/K20 swap; this function is wired directly from the K-series engine layer (seed 0039), so the Miata PCM engine pin is intentionally dead. | mapping-proposal |
| REQUIRED_UNMAPPED | PCM-2-U | BP-ZE engine removed in the K24/K20 swap; this function is wired directly from the K-series engine layer (seed 0039), so the Miata PCM engine pin is intentionally dead. | mapping-proposal |
| REQUIRED_UNMAPPED | PCM-2-V | BP-ZE engine removed in the K24/K20 swap; this function is wired directly from the K-series engine layer (seed 0039), so the Miata PCM engine pin is intentionally dead. | mapping-proposal |
| REQUIRED_UNMAPPED | PCM-2-Y | BP-ZE engine removed in the K24/K20 swap; this function is wired directly from the K-series engine layer (seed 0039), so the Miata PCM engine pin is intentionally dead. | mapping-proposal |
| REQUIRED_UNMAPPED | PCM-2-Z | BP-ZE engine removed in the K24/K20 swap; this function is wired directly from the K-series engine layer (seed 0039), so the Miata PCM engine pin is intentionally dead. | mapping-proposal |
| UNMAPPED | PCM | Optional NA8 functions not wired: clutch switch (pedal-side, tap directly), brake switch (chassis wiring), power-steering pressure switch (1P), MAF ground (2F), O2 (2N), IAT (2P), PRC/ISC/evap solenoids (2R/2W/2X — removed with the BP-ZE), and condenser fan (2S — assign to a spare K-CI pin). | mapping-proposal |
Notes
Maps the K-CI v1 chassis interface (28-way K-CI-01) to the Miata NA8 (1994-97) factory PCM chassis pins. 13 chassis circuits wired; engine pins waived (BP-ZE removed, K-series engine layer wires them directly). DBW/CAN/gauge-sender pins are not applicable to a cable-throttle NA and are left open.
Sources
| Reliability | Kind | Title | URL |
|---|---|---|---|
| 4 | vendor_doc | Link G4X MX5X install manual (NA 1.6/1.8) | https://linkecu.com/documentation/MX5X.pdf |