MX-5 Miata NA8 1996-97 (BP-ZE, 1.8, OBD-II) → FuelTech FT450 (auto)
MX-5 Miata NA8 1996-97 (BP-ZE, 1.8, OBD-II) — FuelTech — FT450
⚠ 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 | 3: read the Findings page before cutting any wire |
| Size of the job | 31 wires · 7 connectors · 0 part lines |
| Tools | Crimp and extraction tools for each terminal family (see Connectors) · wire strippers · multimeter · heat gun + heat-shrink |
| 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-B | SP-14V-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W2 | SP-14V-1 | FT450-A-A13 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W3 | OEM-4-A | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W4 | OEM-4-C | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W5 | OEM-4-D | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W6 | OEM-4-K | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W7 | SP-GND-1 | FT450-A-A7 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W8 | OEM-3-O | SP-0V-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W9 | OEM-4-H | SP-0V-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W10 | SP-0V-1 | FT450-A-A12 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W11 | OEM-3-I | FT450-A-A14 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W12 | OEM-4-E | FT450-A-A18 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W13 | SP-0V-1 | FT450-A-A18 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W14 | OEM-4-G | FT450-A-A17 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W15 | OEM-4-N | FT450-A-A8 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W16 | OEM-4-R | FT450-A-A9 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W17 | OEM-4-U | FT450-A-A1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W18 | OEM-4-V | FT450-A-A2 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W19 | OEM-4-W | FT450-A-A1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W20 | OEM-4-X | FT450-A-A2 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W21 | OEM-3-B | FT450-A-A20 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W22 | OEM-3-F | FT450-A-A21 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W23 | OEM-3-G | FT450-A-A24 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W24 | OEM-1-A | FT450-A-A6 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W25 | OEM-1-B | FT450-A-A3 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W26 | OEM-1-G | FT450-A-A4 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W27 | OEM-1-U | FT450-A-A5 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W28 | OEM-3-H | FT450-A-A22 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W29 | OEM-3-N | FT450-A-A23 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W30 | OEM-3-C | FT450-A-A25 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W31 | OEM-3-K | FT450-A-A26 | 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 |
|---|---|---|---|---|---|
| 1 | FT450-A-A14 | FT450-A-A12 | open (OL) | 5 V sensor reference must not touch sensor ground | |
| 2 | FT450-A-A14 | FT450-A-A7 | open (OL) | 5 V sensor reference must not touch power ground | |
| 3 | FT450-A-A12 | FT450-A-A13 | open (OL) | sensor ground must not touch +12 V supply | |
| 4 | FT450-A-A14 | FT450-A-A13 | open (OL) | 5 V sensor reference must not touch +12 V supply | |
| 5 | FT450-A-A7 | FT450-A-A13 | open (OL) | power ground must not touch +12 V supply |
If any reading doesn't match, stop and get help before powering up.
Revisions
| Rev | Label | By | Date |
|---|---|---|---|
| No revisions yet. | |||
Schematic
Connectors
FT450-A
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| A1 | Injector 1 (Bank A) | — | W17 | — | 0.5 | OEM-4-U | — | — | — |
| A1 | Injector 1 (Bank A) | — | W19 | — | 0.5 | OEM-4-W | — | — | — |
| A10 | Ignition 3 | — | — | — | — | — | — | — | — |
| A11 | Ignition 4 | — | — | — | — | — | — | — | — |
| A12 | Signal ground | — | W10 | — | 0.5 | SP-0V-1 | — | — | — |
| A13 | +12V switched | — | W2 | — | 0.85 | SP-14V-1 | — | — | — |
| A14 | +5V sensor supply | — | W11 | — | 0.5 | OEM-3-I | — | — | — |
| A15 | CAN A LOW | — | — | — | — | — | — | — | — |
| A16 | CAN A HIGH | — | — | — | — | — | — | — | — |
| A17 | Phase input (cam) | — | W14 | — | 0.5 | OEM-4-G | — | — | — |
| A18 | RPM reference (crank -) | — | W12 | — | 0.5 | OEM-4-E | — | — | — |
| A18 | RPM reference (crank -) | — | W13 | — | 0.5 | SP-0V-1 | — | — | — |
| A19 | RPM signal (crank +) | — | — | — | — | — | — | — | — |
| A2 | Injector 2 (Bank A) | — | W18 | — | 0.5 | OEM-4-V | — | — | — |
| A2 | Injector 2 (Bank A) | — | W20 | — | 0.5 | OEM-4-X | — | — | — |
| A20 | White input 1 | — | W21 | — | 0.5 | OEM-3-B | — | — | — |
| A21 | White input 2 | — | W22 | — | 0.5 | OEM-3-F | — | — | — |
| A22 | White input 3 (TPS) | — | W28 | — | 0.5 | OEM-3-H | — | — | — |
| A23 | White input 4 (oil pressure) | — | W29 | — | 0.5 | OEM-3-N | — | — | — |
| A24 | White input 5 (water temp) | — | W23 | — | 0.5 | OEM-3-G | — | — | — |
| A25 | White input 6 (fuel pressure) | — | W30 | — | 0.5 | OEM-3-C | — | — | — |
| A26 | White input 7 (air temp) | — | W31 | — | 0.5 | OEM-3-K | — | — | — |
| A3 | Aux 1 | — | W25 | — | 0.5 | OEM-1-B | — | — | — |
| A4 | Aux 2 | — | W26 | — | 0.5 | OEM-1-G | — | — | — |
| A5 | Aux 3 | — | W27 | — | 0.5 | OEM-1-U | — | — | — |
| A6 | Aux 4 (fuel pump / relays) | — | W24 | — | 0.5 | OEM-1-A | — | — | — |
| A7 | Power ground | — | W7 | — | 0.85 | SP-GND-1 | — | — | — |
| A8 | Ignition 1 | — | W15 | — | 0.5 | OEM-4-N | — | — | — |
| A9 | Ignition 2 | — | W16 | — | 0.5 | OEM-4-R | — | — | — |
OEM-1
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| A | Cooling fan relay (low-side) | — | W24 | — | 0.5 | FT450-A-A6 | — | — | — |
| B | A/C condenser fan relay | — | W25 | — | 0.5 | FT450-A-A3 | — | — | — |
| C | Starter input (12V while cranking) | — | — | — | — | — | — | — | — |
| E | Check engine light (MIL) | — | — | — | — | — | — | — | — |
| G | A/C clutch relay | — | W26 | — | 0.5 | FT450-A-A4 | — | — | — |
| K | A/C pressure switch (A/C request) | — | — | — | — | — | — | — | — |
| L | Clutch switch | — | — | — | — | — | — | — | — |
| M | Vehicle speed sensor (VSS) | — | — | — | — | — | — | — | — |
| Q | Brake switch | — | — | — | — | — | — | — | — |
| U | Fuel pump relay (low-side) | — | W27 | — | 0.5 | FT450-A-A5 | — | — | — |
OEM-3
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| B | MAF sensor input | — | W21 | — | 0.5 | FT450-A-A20 | — | — | — |
| C | Front O2 sensor input | — | W30 | — | 0.5 | FT450-A-A25 | — | — | — |
| D | Rear O2 sensor input | — | — | — | — | — | — | — | — |
| F | Throttle position (TPS) | — | W22 | — | 0.5 | FT450-A-A21 | — | — | — |
| G | Engine coolant temp (CLT) | — | W23 | — | 0.5 | FT450-A-A24 | — | — | — |
| H | EGR boost sensor | — | W28 | — | 0.5 | FT450-A-A22 | — | — | — |
| I | +5V sensor reference | — | W11 | — | 0.5 | FT450-A-A14 | — | — | — |
| J | EGR valve position sensor | — | — | — | — | — | — | — | — |
| K | Intake air temp (IAT) | — | W31 | — | 0.5 | FT450-A-A26 | — | — | — |
| L | Idle switch (closed throttle) | — | — | — | — | — | — | — | — |
| M | Front O2 heater control | — | — | — | — | — | — | — | — |
| N | EGR boost sensor (2nd channel) | — | W29 | — | 0.5 | FT450-A-A23 | — | — | — |
| O | Sensor ground | — | W8 | — | 0.5 | SP-0V-1 | — | — | — |
| P | Power steering pressure switch | — | — | — | — | — | — | — | — |
OEM-4
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| A | Chassis ground | — | W3 | — | 0.85 | SP-GND-1 | — | — | — |
| B | ECU power +12V (main relay) | — | W1 | — | 0.85 | SP-14V-1 | — | — | — |
| C | Chassis ground | — | W4 | — | 0.85 | SP-GND-1 | — | — | — |
| D | Chassis ground | — | W5 | — | 0.85 | SP-GND-1 | — | — | — |
| E | Crank position (CKP) sensor | — | W12 | — | 0.5 | FT450-A-A18 | — | — | — |
| F | CAS SGT (cam trigger) | — | — | — | — | — | — | — | — |
| G | CAS SGC (cam sync) | — | W14 | — | 0.5 | FT450-A-A17 | — | — | — |
| H | Crank pickup timing ground (CKP gnd) | — | W9 | — | 0.5 | SP-0V-1 | — | — | — |
| I | Permanent +12V (battery) | — | — | — | — | — | — | — | — |
| J | PRC solenoid (FPR control) | — | — | — | — | — | — | — | — |
| K | Chassis ground | — | W6 | — | 0.85 | SP-GND-1 | — | — | — |
| L | Tachometer output | — | — | — | — | — | — | — | — |
| N | Ignition coil trigger (cyl 1&4) | — | W15 | — | 0.5 | FT450-A-A8 | — | — | — |
| O | EGR vent solenoid | — | — | — | — | — | — | — | — |
| P | EGR vacuum solenoid | — | — | — | — | — | — | — | — |
| Q | Idle air control (IAC) valve | — | — | — | — | — | — | — | — |
| R | Ignition coil trigger (cyl 2&3) | — | W16 | — | 0.5 | FT450-A-A9 | — | — | — |
| T | EVAP purge solenoid | — | — | — | — | — | — | — | — |
| U | Injector 1 (cyl 1) | — | W17 | — | 0.5 | FT450-A-A1 | — | — | — |
| V | Injector 2 (cyl 2) | — | W18 | — | 0.5 | FT450-A-A2 | — | — | — |
| W | Injector 3 (cyl 3) | — | W19 | — | 0.5 | FT450-A-A1 | — | — | — |
| X | Injector 4 (cyl 4) | — | W20 | — | 0.5 | FT450-A-A2 | — | — | — |
SP-0V
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W8 | — | 0.5 | OEM-3-O | — | — | — |
| 1 | — | — | W9 | — | 0.5 | OEM-4-H | — | — | — |
| 1 | — | — | W10 | — | 0.5 | FT450-A-A12 | — | — | — |
| 1 | — | — | W13 | — | 0.5 | FT450-A-A18 | — | — | — |
SP-14V
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W1 | — | 0.85 | OEM-4-B | — | — | — |
| 1 | — | — | W2 | — | 0.85 | FT450-A-A13 | — | — | — |
SP-GND
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W3 | — | 0.85 | OEM-4-A | — | — | — |
| 1 | — | — | W4 | — | 0.85 | OEM-4-C | — | — | — |
| 1 | — | — | W5 | — | 0.85 | OEM-4-D | — | — | — |
| 1 | — | — | W6 | — | 0.85 | OEM-4-K | — | — | — |
| 1 | — | — | W7 | — | 0.85 | FT450-A-A7 | — | — | — |
Pin map
| OEM point | OEM function | OEM family | Target point | Target function | Target family | Wire colour | Evidence |
|---|---|---|---|---|---|---|---|
| OEM-1-A | Cooling fan relay (low-side) | low_side_out | FT450-A-A6 | Aux 4 (fuel pump / relays) | low_side_out | corroborated | |
| OEM-1-B | A/C condenser fan relay | low_side_out | FT450-A-A3 | Aux 1 | low_side_out | corroborated | |
| OEM-1-C | Starter input (12V while cranking) | digital_in | — | — | — | corroborated | |
| OEM-1-E | Check engine light (MIL) | low_side_out | — | — | — | corroborated | |
| OEM-1-G | A/C clutch relay | low_side_out | FT450-A-A4 | Aux 2 | low_side_out | corroborated | |
| OEM-1-K | A/C pressure switch (A/C request) | digital_in | — | — | — | corroborated | |
| OEM-1-L | Clutch switch | digital_in | — | — | — | corroborated | |
| OEM-1-M | Vehicle speed sensor (VSS) | digital_in | — | — | — | corroborated | |
| OEM-1-Q | Brake switch | digital_in | — | — | — | corroborated | |
| OEM-1-U | Fuel pump relay (low-side) | low_side_out | FT450-A-A5 | Aux 3 | low_side_out | corroborated | |
| OEM-3-B | MAF sensor input | analog_in | FT450-A-A20 | White input 1 | analog_in | corroborated | |
| OEM-3-C | Front O2 sensor input | lambda_nb_in | FT450-A-A25 | White input 6 (fuel pressure) | analog_in | corroborated | |
| OEM-3-D | Rear O2 sensor input | lambda_nb_in | — | — | — | corroborated | |
| OEM-3-F | Throttle position (TPS) | analog_in | FT450-A-A21 | White input 2 | analog_in | corroborated | |
| OEM-3-G | Engine coolant temp (CLT) | temp_in | FT450-A-A24 | White input 5 (water temp) | temp_in | corroborated | |
| OEM-3-H | EGR boost sensor | analog_in | FT450-A-A22 | White input 3 (TPS) | analog_in | corroborated | |
| OEM-3-I | +5V sensor reference | vref | FT450-A-A14 | +5V sensor supply | vref | corroborated | |
| OEM-3-J | EGR valve position sensor | analog_in | — | — | — | corroborated | |
| OEM-3-K | Intake air temp (IAT) | temp_in | FT450-A-A26 | White input 7 (air temp) | temp_in | corroborated | |
| OEM-3-L | Idle switch (closed throttle) | digital_in | — | — | — | corroborated | |
| OEM-3-M | Front O2 heater control | low_side_out | — | — | — | corroborated | |
| OEM-3-N | EGR boost sensor (2nd channel) | analog_in | FT450-A-A23 | White input 4 (oil pressure) | analog_in | corroborated | |
| OEM-3-O | Sensor ground | sensor_ground | FT450-A-A12 + FT450-A-A18 | Signal ground + RPM reference (crank -) | sensor_ground + trigger_in | corroborated | |
| OEM-3-P | Power steering pressure switch | digital_in | — | — | — | corroborated | |
| OEM-4-A | Chassis ground | ground | FT450-A-A7 | Power ground | ground | corroborated | |
| OEM-4-B | ECU power +12V (main relay) | power_in | FT450-A-A13 | +12V switched | power_in | corroborated | |
| OEM-4-C | Chassis ground | ground | FT450-A-A7 | Power ground | ground | corroborated | |
| OEM-4-D | Chassis ground | ground | FT450-A-A7 | Power ground | ground | corroborated | |
| OEM-4-E | Crank position (CKP) sensor | trigger_in | FT450-A-A12 + FT450-A-A18 | Signal ground + RPM reference (crank -) | sensor_ground + trigger_in | corroborated | |
| OEM-4-F | CAS SGT (cam trigger) | trigger_in | — | — | — | corroborated | |
| OEM-4-G | CAS SGC (cam sync) | trigger_in | FT450-A-A17 | Phase input (cam) | trigger_in | corroborated | |
| OEM-4-H | Crank pickup timing ground (CKP gnd) | sensor_ground | FT450-A-A12 + FT450-A-A18 | Signal ground + RPM reference (crank -) | sensor_ground + trigger_in | corroborated | |
| OEM-4-I | Permanent +12V (battery) | power_in | — | — | — | corroborated | |
| OEM-4-J | PRC solenoid (FPR control) | low_side_out | — | — | — | corroborated | |
| OEM-4-K | Chassis ground | ground | FT450-A-A7 | Power ground | ground | corroborated | |
| OEM-4-L | Tachometer output | tacho_out | — | — | — | corroborated | |
| OEM-4-N | Ignition coil trigger (cyl 1&4) | ignition_out | FT450-A-A8 | Ignition 1 | ignition_out | corroborated | |
| OEM-4-O | EGR vent solenoid | low_side_out | — | — | — | corroborated | |
| OEM-4-P | EGR vacuum solenoid | low_side_out | — | — | — | corroborated | |
| OEM-4-Q | Idle air control (IAC) valve | low_side_out | — | — | — | corroborated | |
| OEM-4-R | Ignition coil trigger (cyl 2&3) | ignition_out | FT450-A-A9 | Ignition 2 | ignition_out | corroborated | |
| OEM-4-T | EVAP purge solenoid | low_side_out | — | — | — | corroborated | |
| OEM-4-U | Injector 1 (cyl 1) | injector_out | FT450-A-A1 | Injector 1 (Bank A) | injector_out | corroborated | |
| OEM-4-V | Injector 2 (cyl 2) | injector_out | FT450-A-A2 | Injector 2 (Bank A) | injector_out | corroborated | |
| OEM-4-W | Injector 3 (cyl 3) | injector_out | FT450-A-A1 | Injector 1 (Bank A) | injector_out | corroborated | |
| OEM-4-X | Injector 4 (cyl 4) | injector_out | FT450-A-A2 | Injector 2 (Bank A) | injector_out | corroborated |
Cut list
| Wire | From | To | Gauge (mm²) | Colour | Length | Signal | Ident |
|---|---|---|---|---|---|---|---|
| W1 | OEM-4-B | SP-14V-1 | 0.85 | no route | ECU power +12V (main relay) | — | |
| W2 | SP-14V-1 | FT450-A-A13 | 0.85 | no route | +12V switched | — | |
| W3 | OEM-4-A | SP-GND-1 | 0.85 | no route | Chassis ground | — | |
| W4 | OEM-4-C | SP-GND-1 | 0.85 | no route | Chassis ground | — | |
| W5 | OEM-4-D | SP-GND-1 | 0.85 | no route | Chassis ground | — | |
| W6 | OEM-4-K | SP-GND-1 | 0.85 | no route | Chassis ground | — | |
| W7 | SP-GND-1 | FT450-A-A7 | 0.85 | no route | Power ground | — | |
| W8 | OEM-3-O | SP-0V-1 | 0.5 | no route | Sensor ground | — | |
| W9 | OEM-4-H | SP-0V-1 | 0.5 | no route | Crank pickup timing ground (CKP gnd) | — | |
| W10 | SP-0V-1 | FT450-A-A12 | 0.5 | no route | Signal ground | — | |
| W11 | OEM-3-I | FT450-A-A14 | 0.5 | no route | +5V sensor reference | — | |
| W12 | OEM-4-E | FT450-A-A18 | 0.5 | no route | Crank position (CKP) sensor | — | |
| W13 | SP-0V-1 | FT450-A-A18 | 0.5 | no route | RPM reference (crank -) | — | |
| W14 | OEM-4-G | FT450-A-A17 | 0.5 | no route | CAS SGC (cam sync) | — | |
| W15 | OEM-4-N | FT450-A-A8 | 0.5 | no route | Ignition coil trigger (cyl 1&4) | — | |
| W16 | OEM-4-R | FT450-A-A9 | 0.5 | no route | Ignition coil trigger (cyl 2&3) | — | |
| W17 | OEM-4-U | FT450-A-A1 | 0.5 | no route | Injector 1 (cyl 1) | — | |
| W18 | OEM-4-V | FT450-A-A2 | 0.5 | no route | Injector 2 (cyl 2) | — | |
| W19 | OEM-4-W | FT450-A-A1 | 0.5 | no route | Injector 3 (cyl 3) | — | |
| W20 | OEM-4-X | FT450-A-A2 | 0.5 | no route | Injector 4 (cyl 4) | — | |
| W21 | OEM-3-B | FT450-A-A20 | 0.5 | no route | MAF sensor input | — | |
| W22 | OEM-3-F | FT450-A-A21 | 0.5 | no route | Throttle position (TPS) | — | |
| W23 | OEM-3-G | FT450-A-A24 | 0.5 | no route | Engine coolant temp (CLT) | — | |
| W24 | OEM-1-A | FT450-A-A6 | 0.5 | no route | Cooling fan relay (low-side) | — | |
| W25 | OEM-1-B | FT450-A-A3 | 0.5 | no route | A/C condenser fan relay | — | |
| W26 | OEM-1-G | FT450-A-A4 | 0.5 | no route | A/C clutch relay | — | |
| W27 | OEM-1-U | FT450-A-A5 | 0.5 | no route | Fuel pump relay (low-side) | — | |
| W28 | OEM-3-H | FT450-A-A22 | 0.5 | no route | EGR boost sensor | — | |
| W29 | OEM-3-N | FT450-A-A23 | 0.5 | no route | EGR boost sensor (2nd channel) | — | |
| W30 | OEM-3-C | FT450-A-A25 | 0.5 | no route | Front O2 sensor input | — | |
| W31 | OEM-3-K | FT450-A-A26 | 0.5 | no route | Intake air temp (IAT) | — |
Bill of materials
| Category | Part number | Manufacturer | Description | Qty | Unit |
|---|
ECU setup sheet
| Role | Engine ref | Engine signal | Sensor | ECU point | ECU function | ECU class | Setup flag |
|---|---|---|---|---|---|---|---|
| No configured channels. | |||||||
Findings
Open (9)
| Severity | Code | Subject | Message |
|---|---|---|---|
| error | NET_MERGED | FT450-A-A1 + OEM-4-U + OEM-4-W | 2 different OEM functions share one net: OEM-4-U Injector 1 (cyl 1); OEM-4-W Injector 3 (cyl 3) |
| error | NET_MERGED | FT450-A-A2 + OEM-4-V + OEM-4-X | 2 different OEM functions share one net: OEM-4-V Injector 2 (cyl 2); OEM-4-X Injector 4 (cyl 4) |
| error | REQUIRED_UNMAPPED | OEM-4-F | Required OEM function "CAS SGT (cam trigger)" (trigger_in) is not connected to the new ECU. |
| warn | LOAD_UNKNOWN | FT450-A-A3 | FT450-A-A3 "Aux 1" drives OEM-1-B A/C condenser fan relay (load 0.2 A) but its current rating is unknown. Check the ECU manual. |
| warn | LOAD_UNKNOWN | FT450-A-A4 | FT450-A-A4 "Aux 2" drives OEM-1-G A/C clutch relay (load 0.2 A) but its current rating is unknown. Check the ECU manual. |
| warn | LOAD_UNKNOWN | FT450-A-A5 | FT450-A-A5 "Aux 3" drives OEM-1-U Fuel pump relay (low-side) (load 0.2 A) but its current rating is unknown. Check the ECU manual. |
| warn | LOAD_UNKNOWN | FT450-A-A6 | FT450-A-A6 "Aux 4 (fuel pump / relays)" drives OEM-1-A Cooling fan relay (low-side) (load 0.2 A) but its current rating is unknown. Check the ECU manual. |
| info | NET_FAMILY | FT450-A-A12 ↔ FT450-A-A18 | FT450-A-A12 "Signal ground" [sensor_ground] is wired to FT450-A-A18 "RPM reference (crank -)" [trigger_in]. Trigger return tied to sensor/trigger ground: correct for single-ended trigger inputs. |
| info | UNMAPPED | OEM | 17 optional OEM pins are not mapped: OEM-1-C Starter input (12V while cranking); OEM-1-E Check engine light (MIL); OEM-1-K A/C pressure switch (A/C request); OEM-1-L Clutch switch; OEM-1-M Vehicle speed sensor (VSS); OEM-1-Q Brake switch; OEM-3-D Rear O2 sensor input; OEM-3-J EGR valve position sensor; OEM-3-L Idle switch (closed throttle); OEM-3-M Front O2 heater control; OEM-3-P Power steering pressure switch; OEM-4-J PRC solenoid (FPR control); OEM-4-L Tachometer output; OEM-4-O EGR vent solenoid; OEM-4-P EGR vacuum solenoid; OEM-4-Q Idle air control (IAC) valve; OEM-4-T EVAP purge solenoid |
Accepted (1)
| Code | Subject | Reason | By |
|---|---|---|---|
| REQUIRED_UNMAPPED | OEM-4-I | Battery-constant (memory) feed of the stock ECU: the new ECU has no such input, so it is not needed. | mapping-proposal |
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: - OEM-4 F: CAS SGT (cam trigger): no free cam_hall/cam_vr/frequency_in input on FuelTech FT450 Not wired: - OEM-4 I: Permanent +12V (battery): FuelTech FT450 has no battery-constant input; not needed - OEM-3 M: Front O2 heater control: no free heater_low_side/low_side/relay_control/ls_hs/injector on FuelTech FT450 - OEM-1 E: Check engine light (MIL): no free low_side/relay_control/heater_low_side/ls_hs/injector on FuelTech FT450 - OEM-4 J: PRC solenoid (FPR control): no free low_side/relay_control/heater_low_side/ls_hs/injector on FuelTech FT450 - OEM-4 O: EGR vent solenoid: no free low_side/relay_control/heater_low_side/ls_hs/injector on FuelTech FT450 - OEM-4 P: EGR vacuum solenoid: no free low_side/relay_control/heater_low_side/ls_hs/injector on FuelTech FT450 - OEM-4 Q: Idle air control (IAC) valve: no free low_side/relay_control/heater_low_side/ls_hs/injector on FuelTech FT450 - OEM-4 T: EVAP purge solenoid: no free low_side/relay_control/heater_low_side/ls_hs/injector on FuelTech FT450 - OEM-4 L: Tachometer output: no free tacho/frequency_out/low_side/ls_hs on FuelTech FT450 - OEM-3 D: Rear O2 sensor input: no free o2_narrowband/analog_0_5 on FuelTech FT450 - OEM-3 J: EGR valve position sensor: no free analog_0_5 on FuelTech FT450 - OEM-1 M: Vehicle speed sensor (VSS): no free frequency_in/switch_in on FuelTech FT450 - OEM-1 C: Starter input (12V while cranking): no free switch_in/frequency_in/analog_0_5 on FuelTech FT450 - OEM-1 K: A/C pressure switch (A/C request): no free switch_in/frequency_in/analog_0_5 on FuelTech FT450 - OEM-1 L: Clutch switch: no free switch_in/frequency_in/analog_0_5 on FuelTech FT450 - OEM-1 Q: Brake switch: no free switch_in/frequency_in/analog_0_5 on FuelTech FT450 - OEM-3 L: Idle switch (closed throttle): no free switch_in/frequency_in/analog_0_5 on FuelTech FT450 - OEM-3 P: Power steering pressure switch: no free switch_in/frequency_in/analog_0_5 on FuelTech FT450
Sources
| Reliability | Kind | Title | URL | Archive | Captured | SHA-256 |
|---|---|---|---|---|---|---|
| 4 | vendor_doc | AEM EMS 30-1720 Plug-and-Play adapter manual (1996-97 Miata) | https://static.summitracing.com/global/images/instructions/avm-30-1720.pdf | — | — | — |
| 4 | vendor_doc | FuelTech FT450/FT550 ready harness manual (4 & 6 cylinder) — FT450 Connector A pinout | http://ftmanager.fueltech.com.br/downloads/manual/Portugues/Chicote_pronto_FT450-FT550.pdf | — | — | — |
| 3 | community_copy | Mellens.net: 1996 Mazda Miata wiring diagrams (FSM-derived) | http://www.mellens.net/mazda/mazda_miata_extra_manual/1996_wiring.pdf | — | — | — |