MX-5 Miata Mazdaspeed 2004-05 (BP-ZET turbo, no VVT) → Emtron KV8 (auto)
MX-5 Miata Mazdaspeed 2004-05 (BP-ZET turbo, no VVT) — Emtron — KV8
⚠ NOT CHECKED. Don't build from this.
Drawn by Michael Gnankou · Rev 0 · draft · 2026-10-12
Before you start
Not confident with automotive wiring? Have a professional harness builder or tuner do it, or check your work before first power-up. A wiring mistake can damage the ECU, the engine or the car, or start a fire.
| Status | draft · not yet verified: nobody has reported building and running this harness |
|---|---|
| Open errors | 5: read the Findings page before cutting any wire |
| Size of the job | 2 wires · 5 connectors · 5 part lines |
| Tools | Crimp and extraction tools for each terminal family (see Connectors) · wire strippers · multimeter · heat gun + heat-shrink |
| Terminals | 3-1447221-4 |
| Order of work | 1. Check every part against the parts list. 2. Cut and label every wire (labels: Export → Wire labels). 3. Crimp and pin connector by connector, ticking the build checklist. 4. Run the bench test with nothing plugged in and the battery disconnected. 5. Only then connect the ECU and power up. |
Build checklist
Tick each box as you go. Continuity: meter from end to end, expect under 1 Ω.
| Wire | From | To | Gauge | Colour | Cut | Label | Crimp A | Crimp B | Pin A | Pin B | Continuity |
|---|---|---|---|---|---|---|---|---|---|---|---|
| W1 | OEM-4-AE | KV8-C-2 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W2 | OEM-4-R | KV8-C-3 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ |
Bench test (before first power-up)
Battery disconnected, ECU and every sensor unplugged. Meter on resistance. Each pair below must read open (OL): a reading means a pinched wire, a stray strand or a mis-pinned cavity. Then check continuity of every wire (last column of the build checklist).
| # | Probe A | Probe B | Expect | Why | Reading |
|---|---|---|---|---|---|
| No supply/ground nets found to cross-check. | |||||
If any reading doesn't match, stop and get help before powering up.
Revisions
| Rev | Label | By | Date |
|---|---|---|---|
| No revisions yet. | |||
Schematic
Connectors
KV8-A
Mating face
Wire side
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | — | — | — | — | — | — | — |
| 2 | — | — | — | — | — | — | — | — | — |
| 3 | — | — | — | — | — | — | — | — | — |
| 4 | — | — | — | — | — | — | — | — | — |
| 5 | — | — | — | — | — | — | — | — | — |
| 6 | — | — | — | — | — | — | — | — | — |
| 7 | — | — | — | — | — | — | — | — | — |
| 8 | — | — | — | — | — | — | — | — | — |
| 9 | — | — | — | — | — | — | — | — | — |
| 10 | Lambda 1 heater − | — | — | — | — | — | — | — | — |
| 11 | Lambda 2 heater − | — | — | — | — | — | — | — | — |
| 12 | — | — | — | — | — | — | — | — | — |
| 13 | — | — | — | — | — | — | — | — | — |
| 14 | — | — | — | — | — | — | — | — | — |
| 15 | — | — | — | — | — | — | — | — | — |
| 16 | Lambda 1 heater + | — | — | — | — | — | — | — | — |
| 17 | Lambda 2 heater + | — | — | — | — | — | — | — | — |
| 18 | Lambda 1 Nernst cell (Vs) | — | — | — | — | — | — | — | — |
| 19 | — | — | — | — | — | — | — | — | — |
| 20 | Lambda 2 cal resistor | — | — | — | — | — | — | — | — |
| 21 | Lambda 2 Nernst cell (Vs) | — | — | — | — | — | — | — | — |
| 22 | Lambda 2 pump cell (Ip) | — | — | — | — | — | — | — | — |
| 23 | Lambda 2 virtual ground | — | — | — | — | — | — | — | — |
| 24 | Lambda 1 cal resistor | — | — | — | — | — | — | — | — |
| 25 | Lambda 1 pump cell (Ip) | — | — | — | — | — | — | — | — |
| 26 | Lambda 1 virtual ground | — | — | — | — | — | — | — | — |
KV8-B
Mating face
Wire side
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | Injection 1 | — | — | — | — | — | — | — | — |
| 2 | Injection 2 | — | — | — | — | — | — | — | — |
| 3 | Injection 3 | — | — | — | — | — | — | — | — |
| 4 | Injection 4 | — | — | — | — | — | — | — | — |
| 5 | Injection 5 | — | — | — | — | — | — | — | — |
| 6 | Injection 6 | — | — | — | — | — | — | — | — |
| 7 | Injection 7 | — | — | — | — | — | — | — | — |
| 8 | Injection 8 | — | — | — | — | — | — | — | — |
| 9 | ECU ground | — | — | — | — | — | — | — | — |
| 10 | Aux 1 | — | — | — | — | — | — | — | — |
| 11 | Aux 2 | — | — | — | — | — | — | — | — |
| 12 | Aux 3 | — | — | — | — | — | — | — | — |
| 13 | Aux 4 | — | — | — | — | — | — | — | — |
| 14 | Aux 5 | — | — | — | — | — | — | — | — |
| 15 | Aux 6 | — | — | — | — | — | — | — | — |
| 16 | Aux 7 | — | — | — | — | — | — | — | — |
| 17 | Aux 8 | — | — | — | — | — | — | — | — |
| 18 | Aux 9 | — | — | — | — | — | — | — | — |
| 19 | Aux 10 | — | — | — | — | — | — | — | — |
| 20 | Aux 11 | — | — | — | — | — | — | — | — |
| 21 | Aux 12 | — | — | — | — | — | — | — | — |
| 22 | Aux 13 | — | — | — | — | — | — | — | — |
| 23 | Aux 14 | — | — | — | — | — | — | — | — |
| 24 | Aux 15 | — | — | — | — | — | — | — | — |
| 25 | Aux 16 | — | — | — | — | — | — | — | — |
| 26 | Ignition 1 | — | — | — | — | — | — | — | — |
| 27 | Ignition 2 | — | — | — | — | — | — | — | — |
| 28 | Ignition 3 | — | — | — | — | — | — | — | — |
| 29 | Ignition 4 | — | — | — | — | — | — | — | — |
| 30 | Ignition 5 | — | — | — | — | — | — | — | — |
| 31 | Ignition 6 | — | — | — | — | — | — | — | — |
| 32 | Ignition 7 | — | — | — | — | — | — | — | — |
| 33 | Ignition 8 | — | — | — | — | — | — | — | — |
| 34 | ECU ground | — | — | — | — | — | — | — | — |
KV8-C
Mating face
Wire side
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | ECU ground | — | — | — | — | — | — | — | — |
| 2 | Analog in 1 | — | W1 | — | 0.5 | OEM-4-AE | — | — | — |
| 3 | Analog in 2 | — | W2 | — | 0.5 | OEM-4-R | — | — | — |
| 4 | Analog in 3 | — | — | — | — | — | — | — | — |
| 5 | Analog in 4 | — | — | — | — | — | — | — | — |
| 6 | Analog in 5 | — | — | — | — | — | — | — | — |
| 7 | Analog in 6 | — | — | — | — | — | — | — | — |
| 8 | Analog in 7 | — | — | — | — | — | — | — | — |
| 9 | Analog in 8 | — | — | — | — | — | — | — | — |
| 10 | Analog in 9 | — | — | — | — | — | — | — | — |
| 11 | Analog in 10 | — | — | — | — | — | — | — | — |
| 12 | Analog in 11 | — | — | — | — | — | — | — | — |
| 13 | Analog in 12 | — | — | — | — | — | — | — | — |
| 14 | Analog in 13 | — | — | — | — | — | — | — | — |
| 15 | Analog in 14 | — | — | — | — | — | — | — | — |
| 16 | Analog in 15 | — | — | — | — | — | — | — | — |
| 17 | Analog sensor 0V reference | — | — | — | — | — | — | — | — |
| 18 | Digital in 9 | — | — | — | — | — | — | — | — |
| 19 | Digital in 10 | — | — | — | — | — | — | — | — |
| 20 | Digital in 11 | — | — | — | — | — | — | — | — |
| 21 | Digital in 12 | — | — | — | — | — | — | — | — |
| 22 | Digital in 13 | — | — | — | — | — | — | — | — |
| 23 | Digital in 14 | — | — | — | — | — | — | — | — |
| 24 | Analog in 16 | — | — | — | — | — | — | — | — |
| 25 | Analog sensor 0V reference | — | — | — | — | — | — | — | — |
| 26 | ECU ground | — | — | — | — | — | — | — | — |
| 27 | Digital in 1 | — | — | — | — | — | — | — | — |
| 28 | Digital in 2 | — | — | — | — | — | — | — | — |
| 29 | Digital in 3 | — | — | — | — | — | — | — | — |
| 30 | Digital in 4 | — | — | — | — | — | — | — | — |
| 31 | Digital in 5 | — | — | — | — | — | — | — | — |
| 32 | Digital in 6 | — | — | — | — | — | — | — | — |
| 33 | Digital in 7 | — | — | — | — | — | — | — | — |
| 34 | Digital in 8 | — | — | — | — | — | — | — | — |
KV8-D
Mating face
Wire side
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | ECU 14V supply | — | — | — | — | — | — | — | — |
| 2 | Aux 13–16 14V supply | — | — | — | — | — | — | — | — |
| 3 | Sensor supply 8V | — | — | — | — | — | — | — | — |
| 4 | Crank index sensor + | — | — | — | — | — | — | — | — |
| 5 | Crank index sensor − | — | — | — | — | — | — | — | — |
| 6 | Sync sensor + | — | — | — | — | — | — | — | — |
| 7 | Sync sensor − | — | — | — | — | — | — | — | — |
| 8 | CAN 1 H | — | — | — | — | — | — | — | — |
| 9 | EFI relay output (low side, 200 mA) | — | — | — | — | — | — | — | — |
| 10 | CAN 2 H | — | — | — | — | — | — | — | — |
| 11 | Knock 1 + | — | — | — | — | — | — | — | — |
| 12 | Knock 1 − | — | — | — | — | — | — | — | — |
| 13 | Shield (crank/cam/knock) | — | — | — | — | — | — | — | — |
| 14 | CAN 1 L | — | — | — | — | — | — | — | — |
| 15 | Ignition switch input | — | — | — | — | — | — | — | — |
| 16 | CAN 2 L | — | — | — | — | — | — | — | — |
| 17 | Knock 2 + | — | — | — | — | — | — | — | — |
| 18 | Knock 2 − | — | — | — | — | — | — | — | — |
| 19 | Analog output 0–5V | — | — | — | — | — | — | — | — |
| 20 | Aux 9–12 14V supply | — | — | — | — | — | — | — | — |
| 21 | Sensor supply Vref1 5.0V | — | — | — | — | — | — | — | — |
| 22 | Sensor supply Vref2 5.0V | — | — | — | — | — | — | — | — |
| 23 | Ethernet Tx+ | — | — | — | — | — | — | — | — |
| 24 | Ethernet Tx− | — | — | — | — | — | — | — | — |
| 25 | Ethernet Rx+ | — | — | — | — | — | — | — | — |
| 26 | Ethernet Rx− | — | — | — | — | — | — | — | — |
OEM-4
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| AC | Data link connector (DLC TEN, turbo) | — | — | — | — | — | — | — | — |
| AE | BARO/MAP sensor (turbo boost pressure) | — | W1 | — | 0.5 | KV8-C-2 | — | — | — |
| D | Boost control solenoid (turbo) | — | — | — | — | — | — | — | — |
| E | Boost control solenoid (turbo) | — | — | — | — | — | — | — | — |
| R | Intake air temperature 2 (IAT2, turbo) | — | W2 | — | 0.5 | KV8-C-3 | — | — | — |
Pin map
| OEM point | OEM function | OEM family | Target point | Target function | Target family | Wire colour | Evidence |
|---|---|---|---|---|---|---|---|
| OEM-4-AC | Data link connector (DLC TEN, turbo) | serial | — | — | — | BrY | single_source |
| OEM-4-AE | BARO/MAP sensor (turbo boost pressure) | analog_in | KV8-C-2 | Analog in 1 | analog_in | LY | single_source |
| OEM-4-D | Boost control solenoid (turbo) | high_side_out | — | — | — | Y | single_source |
| OEM-4-E | Boost control solenoid (turbo) | high_side_out | — | — | — | Y | single_source |
| OEM-4-R | Intake air temperature 2 (IAT2, turbo) | temp_in | KV8-C-3 | Analog in 2 | analog_in | VY | single_source |
Cut list
| Wire | From | To | Gauge (mm²) | Colour | Length | Signal | Ident |
|---|---|---|---|---|---|---|---|
| W1 | OEM-4-AE | KV8-C-2 | 0.5 | no route | BARO/MAP sensor (turbo boost pressure) | — | |
| W2 | OEM-4-R | KV8-C-3 | 0.5 | no route | Intake air temperature 2 (IAT2, turbo) | — |
Bill of materials
| Category | Part number | Manufacturer | Description | Qty | Unit |
|---|---|---|---|---|---|
| connector | 3-1437290-7 | TE | Superseal 1.0 26-way plug | 1.000 | ea |
| connector | 3-1437290-8 | TE | Superseal 1.0 26-way plug, Key 2 | 1.000 | ea |
| connector | 4-1437290-0 | TE | Superseal 1.0 34-way plug, Key 1 | 1.000 | ea |
| connector | 4-1437290-1 | TE | Superseal 1.0 34-way plug, Key 2 | 1.000 | ea |
| terminal | 3-1447221-4 | TE | Superseal 1.0 socket terminal, 20 AWG (0.5 sq mm) | 2.000 | ea |
ECU setup sheet
| Role | Engine ref | Engine signal | Sensor | ECU point | ECU function | ECU class | Setup flag |
|---|---|---|---|---|---|---|---|
| No configured channels. | |||||||
Findings
Open (8)
| Severity | Code | Subject | Message |
|---|---|---|---|
| error | PHYS_REQUIRED_OPEN | KV8-B-34 | KV8-B-34 "ECU ground" is required but not wired. |
| error | PHYS_REQUIRED_OPEN | KV8-B-9 | KV8-B-9 "ECU ground" is required but not wired. |
| error | PHYS_REQUIRED_OPEN | KV8-C-1 | KV8-C-1 "ECU ground" is required but not wired. |
| error | PHYS_REQUIRED_OPEN | KV8-C-26 | KV8-C-26 "ECU ground" is required but not wired. |
| error | PHYS_REQUIRED_OPEN | KV8-D-1 | KV8-D-1 "ECU 14V supply" is required but not wired. |
| warn | DATASET_GAP | KV8 A | 14 of 26 cavities on KV8 A have no pin data (1,2,3,4,5,6,7,8,9,12,13,14,15,19). Anything there is invisible to these checks. |
| info | NET_FAMILY | OEM-4-R ↔ KV8-C-3 | OEM-4-R "Intake air temperature 2 (IAT2, turbo)" [temp_in] is wired to KV8-C-3 "Analog in 2" [analog_in]. Thermistor on a plain analog input needs a pull-up; check the channel can enable one. |
| info | UNMAPPED | OEM | 3 optional OEM pins are not mapped: OEM-4-AC Data link connector (DLC TEN, turbo); OEM-4-D Boost control solenoid (turbo); OEM-4-E Boost control solenoid (turbo) |
Accepted (0)
| Code | Subject | Reason | By |
|---|
Notes
Auto-mapped by auto_map() from the library pin data on 2026-10-11. Review every wire against both manuals before building. Open items: - Main-relay feed: no ecu_main_power pin on the stock or the new ECU - KV8-B 34: ECU ground: required by Emtron KV8 but no stock pin feeds it; wire by hand - KV8-B 9: ECU ground: required by Emtron KV8 but no stock pin feeds it; wire by hand - KV8-C 1: ECU ground: required by Emtron KV8 but no stock pin feeds it; wire by hand - KV8-C 26: ECU ground: required by Emtron KV8 but no stock pin feeds it; wire by hand - KV8-D 1: ECU 14V supply: required by Emtron KV8 but no stock pin feeds it; wire by hand Not wired: - OEM-4 D: Boost control solenoid (turbo): no free high_side/ls_hs on Emtron KV8 - OEM-4 E: Boost control solenoid (turbo): no free high_side/ls_hs on Emtron KV8 - OEM-4 AC: Data link connector (DLC TEN, turbo): no free k_line on Emtron KV8 - KV8-D 15: Ignition switch input: not fed (the stock ECU has no ignition-sense pin); feed it from a switched-ignition source
Sources
| Reliability | Kind | Title | URL | Archive | Captured | SHA-256 |
|---|---|---|---|---|---|---|
| 4 | oem_manual | 2005 Mazda MX-5 Miata Engine Performance Control System (PCM terminal voltage reference, BP and BP WITH TC) | https://trull.org/alex/pubmirror/www.mellens.net/mazda/Mazda-Miata-2005/engine_control_system.pdf | — | — | — |
| 4 | vendor_doc | Adaptronic eSel039 Select Plugin ECU for Mazda MX5 / Miata NB8B/C (OEM ECU pinout) | https://www.miataturbo.net/attachments/ecus-tuning-54/04-msm-ecu-pinout-104032/nb8bc_oem_ecu_pinouts-224948d1602912806 | — | — | — |
| 2 | user_dataset | Subaru ECU Matcher dataset (hiubin), vehicleId=1 | — | — | — | — |