MX-5 Miata NA8 1994-95 (BP-ZE, 1.8, OBD-I) → AMP EFI MS3Pro Ultimate (auto)
MX-5 Miata NA8 1994-95 (BP-ZE, 1.8, OBD-I) — AMP EFI — MS3Pro Ultimate
Drawn by Michael Gnankou · Rev 0 · proposal · 2026-10-11
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 | proposal · not yet verified: nobody has reported building and running this harness |
|---|---|
| Open errors | none |
| Size of the job | 54 wires · 8 connectors · 2 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-1-B | SP-14V-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W2 | SP-14V-1 | MS3PROULTIMA-A-35 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W3 | OEM-1-A | MS3PROULTIMA-C-23 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W4 | OEM-2-A | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W5 | OEM-2-B | SP-GND-1 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W6 | SP-GND-1 | MS3PROULTIMA-A-13 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W7 | SP-GND-1 | MS3PROULTIMA-B-18 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W8 | SP-GND-1 | MS3PROULTIMA-B-3 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W9 | SP-GND-1 | MS3PROULTIMA-B-5 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W10 | SP-GND-1 | MS3PROULTIMA-B-7 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W11 | SP-GND-1 | MS3PROULTIMA-B-9 | 0.85 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W12 | OEM-2-C | SP-0V-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W13 | OEM-2-D | SP-0V-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W14 | OEM-2-F | SP-0V-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W15 | SP-0V-1 | MS3PROULTIMA-A-16 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W16 | SP-0V-1 | MS3PROULTIMA-A-18 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W17 | SP-0V-1 | MS3PROULTIMA-C-17 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W18 | SP-0V-1 | MS3PROULTIMA-C-18 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W19 | SP-0V-1 | MS3PROULTIMA-C-19 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W20 | SP-0V-1 | MS3PROULTIMA-C-20 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W21 | SP-0V-1 | MS3PROULTIMA-C-21 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W22 | OEM-2-K | MS3PROULTIMA-A-8 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W23 | OEM-2-E | MS3PROULTIMA-A-6 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W24 | SP-0V-1 | MS3PROULTIMA-A-15 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W25 | OEM-2-G | MS3PROULTIMA-A-26 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W26 | SP-0V-1 | MS3PROULTIMA-A-27 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W27 | OEM-1-G | MS3PROULTIMA-B-13 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W28 | OEM-1-H | MS3PROULTIMA-B-14 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W29 | OEM-2-U | MS3PROULTIMA-A-3 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W30 | OEM-2-V | MS3PROULTIMA-A-4 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W31 | OEM-2-Y | MS3PROULTIMA-B-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W32 | OEM-2-Z | MS3PROULTIMA-B-10 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W33 | OEM-2-O | MS3PROULTIMA-A-19 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W34 | OEM-2-M | MS3PROULTIMA-A-9 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W35 | OEM-2-Q | MS3PROULTIMA-A-11 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W36 | OEM-1-J | MS3PROULTIMA-A-28 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W37 | OEM-1-R | MS3PROULTIMA-A-14 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W38 | OEM-2-S | MS3PROULTIMA-C-4 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W39 | OEM-2-T | MS3PROULTIMA-A-29 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W40 | OEM-1-L | MS3PROULTIMA-C-3 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W41 | OEM-2-L | MS3PROULTIMA-A-30 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W42 | OEM-2-W | MS3PROULTIMA-C-2 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W43 | OEM-1-E | MS3PROULTIMA-C-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W44 | OEM-2-R | MS3PROULTIMA-A-1 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W45 | OEM-2-X | MS3PROULTIMA-A-2 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W46 | OEM-2-I | MS3PROULTIMA-A-24 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W47 | OEM-2-N | MS3PROULTIMA-A-25 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W48 | OEM-2-P | MS3PROULTIMA-A-10 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W49 | OEM-1-M | MS3PROULTIMA-B-28 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W50 | OEM-1-C | MS3PROULTIMA-A-32 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W51 | OEM-1-O | MS3PROULTIMA-B-20 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W52 | OEM-1-P | MS3PROULTIMA-B-29 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W53 | OEM-1-Q | MS3PROULTIMA-C-11 | 0.5 | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | ☐ | |
| W54 | OEM-1-V | MS3PROULTIMA-C-10 | 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 | MS3PROULTIMA-A-35 | MS3PROULTIMA-A-13 | open (OL) | +12 V supply must not touch power ground | |
| 2 | MS3PROULTIMA-A-35 | MS3PROULTIMA-A-15 | open (OL) | +12 V supply must not touch sensor ground | |
| 3 | MS3PROULTIMA-C-23 | MS3PROULTIMA-A-13 | open (OL) | +12 V supply must not touch power ground | |
| 4 | MS3PROULTIMA-C-23 | MS3PROULTIMA-A-15 | open (OL) | +12 V supply must not touch sensor ground | |
| 5 | MS3PROULTIMA-A-13 | MS3PROULTIMA-A-8 | open (OL) | power ground must not touch 5 V sensor reference | |
| 6 | MS3PROULTIMA-A-15 | MS3PROULTIMA-A-8 | open (OL) | sensor ground must not touch 5 V sensor reference | |
| 7 | MS3PROULTIMA-A-35 | MS3PROULTIMA-A-8 | open (OL) | +12 V supply must not touch 5 V sensor reference | |
| 8 | MS3PROULTIMA-C-23 | MS3PROULTIMA-A-8 | open (OL) | +12 V supply must not touch 5 V sensor reference |
If any reading doesn't match, stop and get help before powering up.
Revisions
| Rev | Label | By | Date |
|---|---|---|---|
| No revisions yet. | |||
Schematic
Connectors
MS3PROULTIMA-A
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | High current out 1 | — | W44 | — | 0.5 | OEM-2-R | — | — | — |
| 10 | MAT in | — | W48 | — | 0.5 | OEM-2-P | — | — | — |
| 11 | CLT in | — | W35 | — | 0.5 | OEM-2-Q | — | — | — |
| 12 | Analog In 6 | — | — | — | — | — | — | — | — |
| 13 | Power ground | — | W6 | — | 0.85 | SP-GND-1 | — | — | — |
| 14 | PWM / Idle Out 1 | — | W37 | — | 0.5 | OEM-1-R | — | — | — |
| 15 | CKP− | — | W24 | — | 0.5 | SP-0V-1 | — | — | — |
| 16 | Logic ground | — | W15 | — | 0.5 | SP-0V-1 | — | — | — |
| 17 | Analog In 7 | — | — | — | — | — | — | — | — |
| 18 | Sensor return | — | W16 | — | 0.5 | SP-0V-1 | — | — | — |
| 19 | Analog in 1 | — | W33 | — | 0.5 | OEM-2-O | — | — | — |
| 2 | High current out 2 | — | W45 | — | 0.5 | OEM-2-X | — | — | — |
| 20 | Analog in 2 | — | — | — | — | — | — | — | — |
| 21 | Analog in 3 | — | — | — | — | — | — | — | — |
| 22 | Analog In 4 | — | — | — | — | — | — | — | — |
| 23 | Analog In 5 | — | — | — | — | — | — | — | — |
| 24 | Tach out | — | W46 | — | 0.5 | OEM-2-I | — | — | — |
| 25 | O2 in | — | W47 | — | 0.5 | OEM-2-N | — | — | — |
| 26 | CMP+ | — | W25 | — | 0.5 | OEM-2-G | — | — | — |
| 27 | CMP− | — | W26 | — | 0.5 | SP-0V-1 | — | — | — |
| 28 | Fuel pump relay out | — | W36 | — | 0.5 | OEM-1-J | — | — | — |
| 29 | PWM out 2 | — | W39 | — | 0.5 | OEM-2-T | — | — | — |
| 3 | Injector out J | — | W29 | — | 0.5 | OEM-2-U | — | — | — |
| 30 | PWM out 3 | — | W41 | — | 0.5 | OEM-2-L | — | — | — |
| 31 | Knock in 1 | — | — | — | — | — | — | — | — |
| 32 | Digital switched in 1 | — | W50 | — | 0.5 | OEM-1-C | — | — | — |
| 33 | CAN L | — | — | — | — | — | — | — | — |
| 34 | CAN H | — | — | — | — | — | — | — | — |
| 35 | 12V+ switched power in | — | W2 | — | 0.85 | SP-14V-1 | — | — | — |
| 4 | Injector out I | — | W30 | — | 0.5 | OEM-2-V | — | — | — |
| 5 | High current out 3 | — | — | — | — | — | — | — | — |
| 6 | CKP+ | — | W23 | — | 0.5 | OEM-2-E | — | — | — |
| 7 | Knock In 2 | — | — | — | — | — | — | — | — |
| 8 | 5V+ VREF out 1 | — | W22 | — | 0.5 | OEM-2-K | — | — | — |
| 9 | TPS in | — | W34 | — | 0.5 | OEM-2-M | — | — | — |
MS3PROULTIMA-B
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | Injector out A | — | W31 | — | 0.5 | OEM-2-Y | — | — | — |
| 10 | Injector out F | — | W32 | — | 0.5 | OEM-2-Z | — | — | — |
| 11 | Injector out G | — | — | — | — | — | — | — | — |
| 12 | Injector out H | — | — | — | — | — | — | — | — |
| 13 | Spark out G | — | W27 | — | 0.5 | OEM-1-G | — | — | — |
| 14 | Spark out E | — | W28 | — | 0.5 | OEM-1-H | — | — | — |
| 15 | Spark out C | — | — | — | — | — | — | — | — |
| 16 | Spark out H | — | — | — | — | — | — | — | — |
| 17 | Digital frequency in 2 | — | — | — | — | — | — | — | — |
| 18 | Ground | — | W7 | — | 0.85 | SP-GND-1 | — | — | — |
| 19 | Digital switched 12V in | — | — | — | — | — | — | — | — |
| 2 | Injector out B | — | — | — | — | — | — | — | — |
| 20 | Digital switched in 2 | — | W51 | — | 0.5 | OEM-1-O | — | — | — |
| 21 | Digital frequency in 3 | — | — | — | — | — | — | — | — |
| 22 | Digital Frequency in 3 VR+ | — | — | — | — | — | — | — | — |
| 23 | Digital Frequency In 3 VR− | — | — | — | — | — | — | — | — |
| 24 | Spark out F | — | — | — | — | — | — | — | — |
| 25 | Spark out B | — | — | — | — | — | — | — | — |
| 26 | Spark out D | — | — | — | — | — | — | — | — |
| 27 | Spark out A | — | — | — | — | — | — | — | — |
| 28 | Digital frequency in 1 | — | W49 | — | 0.5 | OEM-1-M | — | — | — |
| 29 | Digital switched in 3 | — | W52 | — | 0.5 | OEM-1-P | — | — | — |
| 3 | Ground | — | W8 | — | 0.85 | SP-GND-1 | — | — | — |
| 30 | Stepper IAC out 1B | — | — | — | — | — | — | — | — |
| 31 | Stepper IAC out 1A | — | — | — | — | — | — | — | — |
| 32 | Stepper IAC out 2A | — | — | — | — | — | — | — | — |
| 33 | Stepper IAC out 2B | — | — | — | — | — | — | — | — |
| 34 | Digital Frequency in 1 VR+ | — | — | — | — | — | — | — | — |
| 35 | Digital Frequency in 1 VR− | — | — | — | — | — | — | — | — |
| 4 | Injector out C | — | — | — | — | — | — | — | — |
| 5 | Ground | — | W9 | — | 0.85 | SP-GND-1 | — | — | — |
| 6 | Injector out D | — | — | — | — | — | — | — | — |
| 7 | Ground | — | W10 | — | 0.85 | SP-GND-1 | — | — | — |
| 8 | Injector out E | — | — | — | — | — | — | — | — |
| 9 | Ground | — | W11 | — | 0.85 | SP-GND-1 | — | — | — |
MS3PROULTIMA-C
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | PWM out 5 | — | W43 | — | 0.5 | OEM-1-E | — | — | — |
| 10 | Digital switched in 5 | — | W54 | — | 0.5 | OEM-1-V | — | — | — |
| 11 | Digital switched in 4 | — | W53 | — | 0.5 | OEM-1-Q | — | — | — |
| 12 | Digital I/O 5 | — | — | — | — | — | — | — | — |
| 13 | Digital I/O 3 | — | — | — | — | — | — | — | — |
| 14 | Digital I/O 1 | — | — | — | — | — | — | — | — |
| 15 | 5V+ VREF out 2 | — | — | — | — | — | — | — | — |
| 16 | Fuel only battery 12V+ | — | — | — | — | — | — | — | — |
| 17 | Sensor return | — | W17 | — | 0.5 | SP-0V-1 | — | — | — |
| 18 | Sensor return | — | W18 | — | 0.5 | SP-0V-1 | — | — | — |
| 19 | Sensor return | — | W19 | — | 0.5 | SP-0V-1 | — | — | — |
| 2 | PWM out 4 | — | W42 | — | 0.5 | OEM-2-W | — | — | — |
| 20 | Sensor return | — | W20 | — | 0.5 | SP-0V-1 | — | — | — |
| 21 | Sensor return | — | W21 | — | 0.5 | SP-0V-1 | — | — | — |
| 22 | 5V+ VREF out 1 | — | — | — | — | — | — | — | — |
| 23 | Keep alive power | — | W3 | — | 0.85 | OEM-1-A | — | — | — |
| 3 | Digital out 2 | — | W40 | — | 0.5 | OEM-1-L | — | — | — |
| 4 | Digital out 1 | — | W38 | — | 0.5 | OEM-2-S | — | — | — |
| 5 | Digital I/O 4 | — | — | — | — | — | — | — | — |
| 6 | Digital I/O 2 | — | — | — | — | — | — | — | — |
| 7 | Analog in 8 | — | — | — | — | — | — | — | — |
| 8 | 5V+ VREF out 2 | — | — | — | — | — | — | — | — |
| 9 | Fuel only coil negative | — | — | — | — | — | — | — | — |
OEM-1
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| A | Constant +12V | — | W3 | — | 0.85 | MS3PROULTIMA-C-23 | — | — | — |
| B | ECU power +14V (main relay) | — | W1 | — | 0.85 | SP-14V-1 | — | — | — |
| C | Start signal | — | W50 | — | 0.5 | MS3PROULTIMA-A-32 | — | — | — |
| D | Data link connector | — | — | — | — | — | — | — | — |
| E | Malfunction indicator lamp (MIL) | — | W43 | — | 0.5 | MS3PROULTIMA-C-1 | — | — | — |
| G | Ignition 1 (coils 1+4, wasted spark) | — | W27 | — | 0.5 | MS3PROULTIMA-B-13 | — | — | — |
| H | Ignition 2 (coils 2+3, wasted spark) | — | W28 | — | 0.5 | MS3PROULTIMA-B-14 | — | — | — |
| I | Powertrain control module (transmission) | — | — | — | — | — | — | — | — |
| J | A/C relay | — | W36 | — | 0.5 | MS3PROULTIMA-A-28 | — | — | — |
| L | Coolant fan relay | — | W40 | — | 0.5 | MS3PROULTIMA-C-3 | — | — | — |
| M | Vehicle speed | — | W49 | — | 0.5 | MS3PROULTIMA-B-28 | — | — | — |
| N | Powertrain control module (transmission) | — | — | — | — | — | — | — | — |
| O | Stop light switch | — | W51 | — | 0.5 | MS3PROULTIMA-B-20 | — | — | — |
| P | Power steering pressure switch | — | W52 | — | 0.5 | MS3PROULTIMA-B-29 | — | — | — |
| Q | A/C request | — | W53 | — | 0.5 | MS3PROULTIMA-C-11 | — | — | — |
| R | Cooling fan relay | — | W37 | — | 0.5 | MS3PROULTIMA-A-14 | — | — | — |
| S | Heater control unit | — | — | — | — | — | — | — | — |
| T | Unknown | — | — | — | — | — | — | — | — |
| U | Unknown | — | — | — | — | — | — | — | — |
| V | Neutral/clutch switch | — | W54 | — | 0.5 | MS3PROULTIMA-C-10 | — | — | — |
OEM-2
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| A | Power ground | — | W4 | — | 0.85 | SP-GND-1 | — | — | — |
| B | Power ground | — | W5 | — | 0.85 | SP-GND-1 | — | — | — |
| C | Sensor ground (E2) | — | W12 | — | 0.5 | SP-0V-1 | — | — | — |
| D | Sensor ground (E2) | — | W13 | — | 0.5 | SP-0V-1 | — | — | — |
| E | Crank position (CAS NE) | — | W23 | — | 0.5 | MS3PROULTIMA-A-6 | — | — | — |
| F | MAF ground | — | W14 | — | 0.5 | SP-0V-1 | — | — | — |
| G | Cam position (CAS G) | — | W25 | — | 0.5 | MS3PROULTIMA-A-26 | — | — | — |
| H | Data link connector | — | — | — | — | — | — | — | — |
| I | Tachometer output | — | W46 | — | 0.5 | MS3PROULTIMA-A-24 | — | — | — |
| J | EGR function sensor | — | — | — | — | — | — | — | — |
| K | +5V sensor supply | — | W22 | — | 0.5 | MS3PROULTIMA-A-8 | — | — | — |
| L | Rear defroster relay | — | W41 | — | 0.5 | MS3PROULTIMA-A-30 | — | — | — |
| M | Throttle position (TPS) | — | W34 | — | 0.5 | MS3PROULTIMA-A-9 | — | — | — |
| N | O2 sensor | — | W47 | — | 0.5 | MS3PROULTIMA-A-25 | — | — | — |
| O | Mass air flow (MAF) | — | W33 | — | 0.5 | MS3PROULTIMA-A-19 | — | — | — |
| P | Intake air temperature (IAT) | — | W48 | — | 0.5 | MS3PROULTIMA-A-10 | — | — | — |
| Q | Coolant temperature (ECT) | — | W35 | — | 0.5 | MS3PROULTIMA-A-11 | — | — | — |
| R | PRC solenoid (fuel pressure regulator) | — | W44 | — | 0.5 | MS3PROULTIMA-A-1 | — | — | — |
| S | Condenser fan relay | — | W38 | — | 0.5 | MS3PROULTIMA-C-4 | — | — | — |
| T | Fuel pump relay | — | W39 | — | 0.5 | MS3PROULTIMA-A-29 | — | — | — |
| U | Injector 1 | — | W29 | — | 0.5 | MS3PROULTIMA-A-3 | — | — | — |
| V | Injector 2 | — | W30 | — | 0.5 | MS3PROULTIMA-A-4 | — | — | — |
| W | ISC solenoid | — | W42 | — | 0.5 | MS3PROULTIMA-C-2 | — | — | — |
| X | Evap purge solenoid | — | W45 | — | 0.5 | MS3PROULTIMA-A-2 | — | — | — |
| Y | Injector 3 | — | W31 | — | 0.5 | MS3PROULTIMA-B-1 | — | — | — |
| Z | Injector 4 | — | W32 | — | 0.5 | MS3PROULTIMA-B-10 | — | — | — |
SP-0V
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W12 | — | 0.5 | OEM-2-C | — | — | — |
| 1 | — | — | W13 | — | 0.5 | OEM-2-D | — | — | — |
| 1 | — | — | W14 | — | 0.5 | OEM-2-F | — | — | — |
| 1 | — | — | W15 | — | 0.5 | MS3PROULTIMA-A-16 | — | — | — |
| 1 | — | — | W16 | — | 0.5 | MS3PROULTIMA-A-18 | — | — | — |
| 1 | — | — | W17 | — | 0.5 | MS3PROULTIMA-C-17 | — | — | — |
| 1 | — | — | W18 | — | 0.5 | MS3PROULTIMA-C-18 | — | — | — |
| 1 | — | — | W19 | — | 0.5 | MS3PROULTIMA-C-19 | — | — | — |
| 1 | — | — | W20 | — | 0.5 | MS3PROULTIMA-C-20 | — | — | — |
| 1 | — | — | W21 | — | 0.5 | MS3PROULTIMA-C-21 | — | — | — |
| 1 | — | — | W24 | — | 0.5 | MS3PROULTIMA-A-15 | — | — | — |
| 1 | — | — | W26 | — | 0.5 | MS3PROULTIMA-A-27 | — | — | — |
SP-14V
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W1 | — | 0.85 | OEM-1-B | — | — | — |
| 1 | — | — | W2 | — | 0.85 | MS3PROULTIMA-A-35 | — | — | — |
SP-GND
| Cavity | Function | Signal | Wire | Colour | Gauge (mm²) | Destination | Terminal | Seal | Plug |
|---|---|---|---|---|---|---|---|---|---|
| 1 | — | — | W4 | — | 0.85 | OEM-2-A | — | — | — |
| 1 | — | — | W5 | — | 0.85 | OEM-2-B | — | — | — |
| 1 | — | — | W6 | — | 0.85 | MS3PROULTIMA-A-13 | — | — | — |
| 1 | — | — | W7 | — | 0.85 | MS3PROULTIMA-B-18 | — | — | — |
| 1 | — | — | W8 | — | 0.85 | MS3PROULTIMA-B-3 | — | — | — |
| 1 | — | — | W9 | — | 0.85 | MS3PROULTIMA-B-5 | — | — | — |
| 1 | — | — | W10 | — | 0.85 | MS3PROULTIMA-B-7 | — | — | — |
| 1 | — | — | W11 | — | 0.85 | MS3PROULTIMA-B-9 | — | — | — |
Pin map
| OEM point | OEM function | OEM family | Target point | Target function | Target family | Wire colour | Evidence |
|---|---|---|---|---|---|---|---|
| OEM-1-A | Constant +12V | power_in | MS3PROULTIMA-C-23 | Keep alive power | power_in | LR | single_source |
| OEM-1-B | ECU power +14V (main relay) | power_in | MS3PROULTIMA-A-35 | 12V+ switched power in | power_in | WR | single_source |
| OEM-1-C | Start signal | digital_in | MS3PROULTIMA-A-32 | Digital switched in 1 | digital_in | V | single_source |
| OEM-1-D | Data link connector | serial | — | — | — | WG | single_source |
| OEM-1-E | Malfunction indicator lamp (MIL) | low_side_out | MS3PROULTIMA-C-1 | PWM out 5 | low_side_out | YB | single_source |
| OEM-1-G | Ignition 1 (coils 1+4, wasted spark) | ignition_out | MS3PROULTIMA-B-13 | Spark out G | ignition_out | BrY | single_source |
| OEM-1-H | Ignition 2 (coils 2+3, wasted spark) | ignition_out | MS3PROULTIMA-B-14 | Spark out E | ignition_out | Br | single_source |
| OEM-1-I | Powertrain control module (transmission) | — | — | — | — | LW | single_source |
| OEM-1-J | A/C relay | low_side_out | MS3PROULTIMA-A-28 | Fuel pump relay out | low_side_out | single_source | |
| OEM-1-L | Coolant fan relay | low_side_out | MS3PROULTIMA-C-3 | Digital out 2 | low_side_out | BG | single_source |
| OEM-1-M | Vehicle speed | digital_in | MS3PROULTIMA-B-28 | Digital frequency in 1 | digital_in | GR | single_source |
| OEM-1-N | Powertrain control module (transmission) | — | — | — | — | R | single_source |
| OEM-1-O | Stop light switch | digital_in | MS3PROULTIMA-B-20 | Digital switched in 2 | digital_in | GB | single_source |
| OEM-1-P | Power steering pressure switch | digital_in | MS3PROULTIMA-B-29 | Digital switched in 3 | digital_in | LY | single_source |
| OEM-1-Q | A/C request | digital_in | MS3PROULTIMA-C-11 | Digital switched in 4 | digital_in | LgB | single_source |
| OEM-1-R | Cooling fan relay | low_side_out | MS3PROULTIMA-A-14 | PWM / Idle Out 1 | low_side_out | YB | single_source |
| OEM-1-S | Heater control unit | — | — | — | — | LOr | single_source |
| OEM-1-T | Unknown | — | — | — | — | YR | single_source |
| OEM-1-U | Unknown | — | — | — | — | RB | single_source |
| OEM-1-V | Neutral/clutch switch | digital_in | MS3PROULTIMA-C-10 | Digital switched in 5 | digital_in | BrW | single_source |
| OEM-2-A | Power ground | ground | MS3PROULTIMA-A-13 + MS3PROULTIMA-B-18 + MS3PROULTIMA-B-3 + MS3PROULTIMA-B-5 + MS3PROULTIMA-B-7 + MS3PROULTIMA-B-9 | Power ground + Ground + Ground + Ground + Ground + Ground | ground | B | single_source |
| OEM-2-B | Power ground | ground | MS3PROULTIMA-A-13 + MS3PROULTIMA-B-18 + MS3PROULTIMA-B-3 + MS3PROULTIMA-B-5 + MS3PROULTIMA-B-7 + MS3PROULTIMA-B-9 | Power ground + Ground + Ground + Ground + Ground + Ground | ground | B | single_source |
| OEM-2-C | Sensor ground (E2) | sensor_ground | MS3PROULTIMA-A-15 + MS3PROULTIMA-A-16 + MS3PROULTIMA-A-18 + MS3PROULTIMA-A-27 + MS3PROULTIMA-C-17 + MS3PROULTIMA-C-18 + MS3PROULTIMA-C-19 + MS3PROULTIMA-C-20 + MS3PROULTIMA-C-21 | CKP− + Logic ground + Sensor return + CMP− + Sensor return + Sensor return + Sensor return + Sensor return + Sensor return | sensor_ground + trigger_in | BLg | corroborated |
| OEM-2-D | Sensor ground (E2) | sensor_ground | MS3PROULTIMA-A-15 + MS3PROULTIMA-A-16 + MS3PROULTIMA-A-18 + MS3PROULTIMA-A-27 + MS3PROULTIMA-C-17 + MS3PROULTIMA-C-18 + MS3PROULTIMA-C-19 + MS3PROULTIMA-C-20 + MS3PROULTIMA-C-21 | CKP− + Logic ground + Sensor return + CMP− + Sensor return + Sensor return + Sensor return + Sensor return + Sensor return | sensor_ground + trigger_in | BL | corroborated |
| OEM-2-E | Crank position (CAS NE) | trigger_in | MS3PROULTIMA-A-6 | CKP+ | trigger_in | W | single_source |
| OEM-2-F | MAF ground | sensor_ground | MS3PROULTIMA-A-15 + MS3PROULTIMA-A-16 + MS3PROULTIMA-A-18 + MS3PROULTIMA-A-27 + MS3PROULTIMA-C-17 + MS3PROULTIMA-C-18 + MS3PROULTIMA-C-19 + MS3PROULTIMA-C-20 + MS3PROULTIMA-C-21 | CKP− + Logic ground + Sensor return + CMP− + Sensor return + Sensor return + Sensor return + Sensor return + Sensor return | sensor_ground + trigger_in | BR | single_source |
| OEM-2-G | Cam position (CAS G) | trigger_in | MS3PROULTIMA-A-26 | CMP+ | trigger_in | YL | single_source |
| OEM-2-H | Data link connector | serial | — | — | — | LgY | single_source |
| OEM-2-I | Tachometer output | tacho_out | MS3PROULTIMA-A-24 | Tach out | tacho_out | BW | single_source |
| OEM-2-J | EGR function sensor | — | — | — | — | LgR | single_source |
| OEM-2-K | +5V sensor supply | vref | MS3PROULTIMA-A-8 | 5V+ VREF out 1 | vref | LgW | single_source |
| OEM-2-L | Rear defroster relay | low_side_out | MS3PROULTIMA-A-30 | PWM out 3 | low_side_out | LR | single_source |
| OEM-2-M | Throttle position (TPS) | analog_in | MS3PROULTIMA-A-9 | TPS in | analog_in | RB | single_source |
| OEM-2-N | O2 sensor | lambda_nb_in | MS3PROULTIMA-A-25 | O2 in | lambda_nb_in | RL | single_source |
| OEM-2-O | Mass air flow (MAF) | analog_in | MS3PROULTIMA-A-19 | Analog in 1 | analog_in | R | single_source |
| OEM-2-P | Intake air temperature (IAT) | temp_in | MS3PROULTIMA-A-10 | MAT in | temp_in | RB | single_source |
| OEM-2-Q | Coolant temperature (ECT) | temp_in | MS3PROULTIMA-A-11 | CLT in | temp_in | LW | single_source |
| OEM-2-R | PRC solenoid (fuel pressure regulator) | low_side_out | MS3PROULTIMA-A-1 | High current out 1 | low_side_out | YG | single_source |
| OEM-2-S | Condenser fan relay | low_side_out | MS3PROULTIMA-C-4 | Digital out 1 | low_side_out | LW | single_source |
| OEM-2-T | Fuel pump relay | low_side_out | MS3PROULTIMA-A-29 | PWM out 2 | low_side_out | Lg | single_source |
| OEM-2-U | Injector 1 | injector_out | MS3PROULTIMA-A-3 | Injector out J | injector_out | Y | single_source |
| OEM-2-V | Injector 2 | injector_out | MS3PROULTIMA-A-4 | Injector out I | injector_out | YB | single_source |
| OEM-2-W | ISC solenoid | low_side_out | MS3PROULTIMA-C-2 | PWM out 4 | low_side_out | LOr | single_source |
| OEM-2-X | Evap purge solenoid | low_side_out | MS3PROULTIMA-A-2 | High current out 2 | low_side_out | YR | single_source |
| OEM-2-Y | Injector 3 | injector_out | MS3PROULTIMA-B-1 | Injector out A | injector_out | GW | single_source |
| OEM-2-Z | Injector 4 | injector_out | MS3PROULTIMA-B-10 | Injector out F | injector_out | G | single_source |
Cut list
| Wire | From | To | Gauge (mm²) | Colour | Length | Signal | Ident |
|---|---|---|---|---|---|---|---|
| W1 | OEM-1-B | SP-14V-1 | 0.85 | no route | ECU power +14V (main relay) | — | |
| W2 | SP-14V-1 | MS3PROULTIMA-A-35 | 0.85 | no route | 12V+ switched power in | — | |
| W3 | OEM-1-A | MS3PROULTIMA-C-23 | 0.85 | no route | Constant +12V | — | |
| W4 | OEM-2-A | SP-GND-1 | 0.85 | no route | Power ground | — | |
| W5 | OEM-2-B | SP-GND-1 | 0.85 | no route | Power ground | — | |
| W6 | SP-GND-1 | MS3PROULTIMA-A-13 | 0.85 | no route | Power ground | — | |
| W7 | SP-GND-1 | MS3PROULTIMA-B-18 | 0.85 | no route | Ground | — | |
| W8 | SP-GND-1 | MS3PROULTIMA-B-3 | 0.85 | no route | Ground | — | |
| W9 | SP-GND-1 | MS3PROULTIMA-B-5 | 0.85 | no route | Ground | — | |
| W10 | SP-GND-1 | MS3PROULTIMA-B-7 | 0.85 | no route | Ground | — | |
| W11 | SP-GND-1 | MS3PROULTIMA-B-9 | 0.85 | no route | Ground | — | |
| W12 | OEM-2-C | SP-0V-1 | 0.5 | no route | Sensor ground (E2) | — | |
| W13 | OEM-2-D | SP-0V-1 | 0.5 | no route | Sensor ground (E2) | — | |
| W14 | OEM-2-F | SP-0V-1 | 0.5 | no route | MAF ground | — | |
| W15 | SP-0V-1 | MS3PROULTIMA-A-16 | 0.5 | no route | Logic ground | — | |
| W16 | SP-0V-1 | MS3PROULTIMA-A-18 | 0.5 | no route | Sensor return | — | |
| W17 | SP-0V-1 | MS3PROULTIMA-C-17 | 0.5 | no route | Sensor return | — | |
| W18 | SP-0V-1 | MS3PROULTIMA-C-18 | 0.5 | no route | Sensor return | — | |
| W19 | SP-0V-1 | MS3PROULTIMA-C-19 | 0.5 | no route | Sensor return | — | |
| W20 | SP-0V-1 | MS3PROULTIMA-C-20 | 0.5 | no route | Sensor return | — | |
| W21 | SP-0V-1 | MS3PROULTIMA-C-21 | 0.5 | no route | Sensor return | — | |
| W22 | OEM-2-K | MS3PROULTIMA-A-8 | 0.5 | no route | +5V sensor supply | — | |
| W23 | OEM-2-E | MS3PROULTIMA-A-6 | 0.5 | no route | Crank position (CAS NE) | — | |
| W24 | SP-0V-1 | MS3PROULTIMA-A-15 | 0.5 | no route | CKP− | — | |
| W25 | OEM-2-G | MS3PROULTIMA-A-26 | 0.5 | no route | Cam position (CAS G) | — | |
| W26 | SP-0V-1 | MS3PROULTIMA-A-27 | 0.5 | no route | CMP− | — | |
| W27 | OEM-1-G | MS3PROULTIMA-B-13 | 0.5 | no route | Ignition 1 (coils 1+4, wasted spark) | — | |
| W28 | OEM-1-H | MS3PROULTIMA-B-14 | 0.5 | no route | Ignition 2 (coils 2+3, wasted spark) | — | |
| W29 | OEM-2-U | MS3PROULTIMA-A-3 | 0.5 | no route | Injector 1 | — | |
| W30 | OEM-2-V | MS3PROULTIMA-A-4 | 0.5 | no route | Injector 2 | — | |
| W31 | OEM-2-Y | MS3PROULTIMA-B-1 | 0.5 | no route | Injector 3 | — | |
| W32 | OEM-2-Z | MS3PROULTIMA-B-10 | 0.5 | no route | Injector 4 | — | |
| W33 | OEM-2-O | MS3PROULTIMA-A-19 | 0.5 | no route | Mass air flow (MAF) | — | |
| W34 | OEM-2-M | MS3PROULTIMA-A-9 | 0.5 | no route | Throttle position (TPS) | — | |
| W35 | OEM-2-Q | MS3PROULTIMA-A-11 | 0.5 | no route | Coolant temperature (ECT) | — | |
| W36 | OEM-1-J | MS3PROULTIMA-A-28 | 0.5 | no route | A/C relay | — | |
| W37 | OEM-1-R | MS3PROULTIMA-A-14 | 0.5 | no route | Cooling fan relay | — | |
| W38 | OEM-2-S | MS3PROULTIMA-C-4 | 0.5 | no route | Condenser fan relay | — | |
| W39 | OEM-2-T | MS3PROULTIMA-A-29 | 0.5 | no route | Fuel pump relay | — | |
| W40 | OEM-1-L | MS3PROULTIMA-C-3 | 0.5 | no route | Coolant fan relay | — | |
| W41 | OEM-2-L | MS3PROULTIMA-A-30 | 0.5 | no route | Rear defroster relay | — | |
| W42 | OEM-2-W | MS3PROULTIMA-C-2 | 0.5 | no route | ISC solenoid | — | |
| W43 | OEM-1-E | MS3PROULTIMA-C-1 | 0.5 | no route | Malfunction indicator lamp (MIL) | — | |
| W44 | OEM-2-R | MS3PROULTIMA-A-1 | 0.5 | no route | PRC solenoid (fuel pressure regulator) | — | |
| W45 | OEM-2-X | MS3PROULTIMA-A-2 | 0.5 | no route | Evap purge solenoid | — | |
| W46 | OEM-2-I | MS3PROULTIMA-A-24 | 0.5 | no route | Tachometer output | — | |
| W47 | OEM-2-N | MS3PROULTIMA-A-25 | 0.5 | no route | O2 sensor | — | |
| W48 | OEM-2-P | MS3PROULTIMA-A-10 | 0.5 | no route | Intake air temperature (IAT) | — | |
| W49 | OEM-1-M | MS3PROULTIMA-B-28 | 0.5 | no route | Vehicle speed | — | |
| W50 | OEM-1-C | MS3PROULTIMA-A-32 | 0.5 | no route | Start signal | — | |
| W51 | OEM-1-O | MS3PROULTIMA-B-20 | 0.5 | no route | Stop light switch | — | |
| W52 | OEM-1-P | MS3PROULTIMA-B-29 | 0.5 | no route | Power steering pressure switch | — | |
| W53 | OEM-1-Q | MS3PROULTIMA-C-11 | 0.5 | no route | A/C request | — | |
| W54 | OEM-1-V | MS3PROULTIMA-C-10 | 0.5 | no route | Neutral/clutch switch | — |
Bill of materials
| Category | Part number | Manufacturer | Description | Qty | Unit |
|---|---|---|---|---|---|
| connector | 174515-6 | TE | AMP Multilock .040/.070 hybrid 22-pin female harness plug (Miata NA/NB ECU) | 1.000 | ea |
| connector | 174516-6 | TE | AMP Multilock .040/.070 hybrid 26-pin female harness plug (Miata NA/NB ECU) | 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 (2)
| Severity | Code | Subject | Message |
|---|---|---|---|
| info | NET_FAMILY | MS3PROULTIMA-A-18 ↔ MS3PROULTIMA-A-27 | MS3PROULTIMA-A-18 "Sensor return" [sensor_ground] is wired to MS3PROULTIMA-A-27 "CMP−" [trigger_in]. Trigger return tied to sensor/trigger ground: correct for single-ended trigger inputs. |
| info | UNMAPPED | OEM | 8 optional OEM pins are not mapped: OEM-1-D Data link connector; OEM-1-I Powertrain control module (transmission); OEM-1-N Powertrain control module (transmission); OEM-1-S Heater control unit; OEM-1-T Unknown; OEM-1-U Unknown; OEM-2-H Data link connector; OEM-2-J EGR function sensor |
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. Not wired: - OEM-1 D: Data link connector: no free k_line on AMP EFI MS3Pro Ultimate - OEM-2 H: Data link connector: no free k_line on AMP EFI MS3Pro Ultimate - OEM-1 I: Powertrain control module (transmission): not classified in the library; wire by hand - OEM-1 N: Powertrain control module (transmission): not classified in the library; wire by hand - OEM-1 S: Heater control unit: not classified in the library; wire by hand - OEM-1 T: Unknown: not classified in the library; wire by hand - OEM-1 U: Unknown: not classified in the library; wire by hand - OEM-2 J: EGR function sensor: not classified in the library; wire by hand - MS3PROULTIMA-B 19: Digital switched 12V in: 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 | vendor_doc | AMP EFI: MS3Pro Ultimate manual (v1.210, fw 1.5.2) pinout tables | https://cdn.shopify.com/s/files/1/0960/0014/7754/files/MS3Pro_User_Manual_Firmware_1.5.2_ULTIMATE.pdf?v=1760706068 | archive | 2026-10-05 | 71ed7ed81581 |
| 4 | vendor_doc | Link G4X MX5X install manual (NA 1.6/1.8) | https://linkecu.com/documentation/MX5X.pdf | archive | 2026-10-05 | b7f730de9f6e |
| 2 | expert_report | Justin Barrera — Miata NA/NB wiring corrections | — | — | — | — |
| 2 | community_copy | rusefi wiki: 1994 Mazda Miata 1.8 (NA8) ECU pinout | https://github.com/rusefi/rusefi/wiki/Mazda-Miata-1994 | — | 2026-10-08 | 075801b907f4 |