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MX-5 Miata NA6 1990-93 (B6-ZE, 1.6) → AMP EFI Microsquirt (auto)

MX-5 Miata NA6 1990-93 (B6-ZE, 1.6) — AMP EFI — Microsquirt
⚠ NOT CHECKED. Don't build from this.
Drawn by Michael Gnankou · Rev 0 · draft · 2026-10-08

Before you start

Statusdraft · not yet verified: nobody has reported building and running this harness
Open errors2: read the Findings page before cutting any wire
Size of the job29 wires · 6 connectors · 2 part lines
ToolsCrimp and extraction tools for each terminal family (see Connectors) · wire strippers · multimeter · heat gun + heat-shrink
Order of work1. 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.

WireFromToGaugeColourCutLabelCrimp ACrimp BPin APin BContinuity
W1OEM-1-BSP-14V-10.85☐☐☐☐☐☐☐
W2SP-14V-1MICROSQUIRT-A-10.85☐☐☐☐☐☐☐
W3OEM-2-ASP-GND-10.85☐☐☐☐☐☐☐
W4OEM-2-BSP-GND-10.85☐☐☐☐☐☐☐
W5OEM-2-CSP-GND-10.85☐☐☐☐☐☐☐
W6OEM-2-DSP-GND-10.85☐☐☐☐☐☐☐
W7SP-GND-1MICROSQUIRT-A-220.85☐☐☐☐☐☐☐
W8SP-GND-1MICROSQUIRT-A-230.85☐☐☐☐☐☐☐
W9OEM-2-FSP-0V-10.5☐☐☐☐☐☐☐
W10SP-0V-1MICROSQUIRT-A-180.5☐☐☐☐☐☐☐
W11SP-0V-1MICROSQUIRT-A-190.5☐☐☐☐☐☐☐
W12SP-0V-1MICROSQUIRT-A-200.5☐☐☐☐☐☐☐
W13OEM-2-KMICROSQUIRT-A-280.5☐☐☐☐☐☐☐
W14OEM-2-EMICROSQUIRT-A-320.5☐☐☐☐☐☐☐
W15OEM-2-GMICROSQUIRT-A-40.5☐☐☐☐☐☐☐
W16OEM-1-GMICROSQUIRT-A-110.5☐☐☐☐☐☐☐
W17OEM-1-HMICROSQUIRT-A-120.5☐☐☐☐☐☐☐
W18OEM-2-UMICROSQUIRT-A-90.5☐☐☐☐☐☐☐
W19OEM-2-VMICROSQUIRT-A-100.5☐☐☐☐☐☐☐
W20OEM-1-EMICROSQUIRT-A-160.5☐☐☐☐☐☐☐
W21OEM-2-IMICROSQUIRT-A-350.5☐☐☐☐☐☐☐
W22OEM-2-OMICROSQUIRT-A-50.5☐☐☐☐☐☐☐
W23OEM-2-NMICROSQUIRT-A-340.5☐☐☐☐☐☐☐
W24OEM-2-QMICROSQUIRT-A-250.5☐☐☐☐☐☐☐
W25OEM-2-PMICROSQUIRT-A-260.5☐☐☐☐☐☐☐
W26OEM-1-CMICROSQUIRT-A-300.5☐☐☐☐☐☐☐
W27OEM-1-NMICROSQUIRT-A-310.5☐☐☐☐☐☐☐
W28OEM-1-PMICROSQUIRT-A-60.5☐☐☐☐☐☐☐
W29OEM-1-QMICROSQUIRT-A-290.5☐☐☐☐☐☐☐

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 AProbe BExpectWhyReading
1MICROSQUIRT-A-1MICROSQUIRT-A-18open (OL)+12 V supply must not touch sensor ground
2MICROSQUIRT-A-1MICROSQUIRT-A-22open (OL)+12 V supply must not touch power ground
3MICROSQUIRT-A-1MICROSQUIRT-A-28open (OL)+12 V supply must not touch 5 V sensor reference
4MICROSQUIRT-A-18MICROSQUIRT-A-28open (OL)sensor ground must not touch 5 V sensor reference
5MICROSQUIRT-A-22MICROSQUIRT-A-28open (OL)power ground must not touch 5 V sensor reference

Revisions

RevLabelByDate
No revisions yet.

Schematic

MICROSQUIRT-AOEM-1OEM-2SP-0VSP-14VSP-GND

Connectors

MICROSQUIRT-A

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1+12V In—W2—0.85SP-14V-1———
10INJ 2—W19—0.5OEM-2-V———
11SPK B (IGN2)—W16—0.5OEM-1-G———
12SPK A (IGN 1)—W17—0.5OEM-1-H———
13RX————————
14TX————————
15BOOT LOAD————————
16ALED—W20—0.5OEM-1-E———
17WLED————————
18Sensor Ground—W10—0.5SP-0V-1———
19Serial Ground—W11—0.5SP-0V-1———
2CANH————————
20Sensor Ground—W12—0.5SP-0V-1———
21VR2-————————
22POWER GROUND—W7—0.85SP-GND-1———
23POWER GROUND—W8—0.85SP-GND-1———
24MAP————————
25CLT—W24—0.5OEM-2-Q———
26MAT—W25—0.5OEM-2-P———
27TPS————————
28TPS VREF (5V)—W13—0.5OEM-2-K———
29SPAREADC—W29—0.5OEM-1-Q———
3CANL————————
30OPTO+—W26—0.5OEM-1-C———
31OPTO-—W27—0.5OEM-1-N———
32VR1+—W14—0.5OEM-2-E———
33VR1-————————
34O2—W23—0.5OEM-2-N———
35TACHO—W21—0.5OEM-2-I———
4VR2+—W15—0.5OEM-2-G———
5SPAREADC2 (MAF)—W22—0.5OEM-2-O———
6FLEX—W28—0.5OEM-1-P———
7FIDLE————————
8FP (pump)————————
9INJ 1—W18—0.5OEM-2-U———

OEM-1

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
AConstant +12V————————
BECU power +14V (main relay)—W1—0.85SP-14V-1———
CStart signal—W26—0.5MICROSQUIRT-A-30———
EMalfunction indicator lamp (MIL)—W20—0.5MICROSQUIRT-A-16———
GIgnition 1 (coils 1+4, wasted spark)—W16—0.5MICROSQUIRT-A-11———
HIgnition 2 (coils 2+3, wasted spark)—W17—0.5MICROSQUIRT-A-12———
NWide-open throttle switch—W27—0.5MICROSQUIRT-A-31———
PPower steering pressure switch—W28—0.5MICROSQUIRT-A-6———
QA/C request—W29—0.5MICROSQUIRT-A-29———
VNeutral/clutch switch————————

OEM-2

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
APower ground—W3—0.85SP-GND-1———
BPower ground—W4—0.85SP-GND-1———
CPower ground—W5—0.85SP-GND-1———
DPower ground—W6—0.85SP-GND-1———
ECrank position (CAS NE)—W14—0.5MICROSQUIRT-A-32———
FAFM ground—W9—0.5SP-0V-1———
GCam position (CAS G)—W15—0.5MICROSQUIRT-A-4———
ITachometer output—W21—0.5MICROSQUIRT-A-35———
K+5V sensor supply—W13—0.5MICROSQUIRT-A-28———
LIdle switch (TPS)————————
NO2 sensor—W23—0.5MICROSQUIRT-A-34———
OAir flow meter (AFM)—W22—0.5MICROSQUIRT-A-5———
PIntake air temperature (IAT)—W25—0.5MICROSQUIRT-A-26———
QCoolant temperature (ECT)—W24—0.5MICROSQUIRT-A-25———
UInjector 1—W18—0.5MICROSQUIRT-A-9———
VInjector 2—W19—0.5MICROSQUIRT-A-10———
YInjector 3————————
ZInjector 4————————

SP-0V

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1——W9—0.5OEM-2-F———
1——W10—0.5MICROSQUIRT-A-18———
1——W11—0.5MICROSQUIRT-A-19———
1——W12—0.5MICROSQUIRT-A-20———

SP-14V

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1——W1—0.85OEM-1-B———
1——W2—0.85MICROSQUIRT-A-1———

SP-GND

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1——W3—0.85OEM-2-A———
1——W4—0.85OEM-2-B———
1——W5—0.85OEM-2-C———
1——W6—0.85OEM-2-D———
1——W7—0.85MICROSQUIRT-A-22———
1——W8—0.85MICROSQUIRT-A-23———

Pin map

OEM pointOEM functionOEM familyTarget pointTarget functionTarget familyWire colourEvidence
OEM-1-AConstant +12Vpower_in———single_source
OEM-1-BECU power +14V (main relay)power_inMICROSQUIRT-A-1+12V Inpower_insingle_source
OEM-1-CStart signaldigital_inMICROSQUIRT-A-30OPTO+digital_insingle_source
OEM-1-EMalfunction indicator lamp (MIL)low_side_outMICROSQUIRT-A-16ALEDlow_side_outsingle_source
OEM-1-GIgnition 1 (coils 1+4, wasted spark)ignition_outMICROSQUIRT-A-11SPK B (IGN2)ignition_outsingle_source
OEM-1-HIgnition 2 (coils 2+3, wasted spark)ignition_outMICROSQUIRT-A-12SPK A (IGN 1)ignition_outsingle_source
OEM-1-NWide-open throttle switchdigital_inMICROSQUIRT-A-31OPTO-digital_insingle_source
OEM-1-PPower steering pressure switchdigital_inMICROSQUIRT-A-6FLEXdigital_insingle_source
OEM-1-QA/C requestdigital_inMICROSQUIRT-A-29SPAREADCanalog_insingle_source
OEM-1-VNeutral/clutch switchdigital_in———single_source
OEM-2-APower groundgroundMICROSQUIRT-A-22 + MICROSQUIRT-A-23POWER GROUND + POWER GROUNDgroundsingle_source
OEM-2-BPower groundgroundMICROSQUIRT-A-22 + MICROSQUIRT-A-23POWER GROUND + POWER GROUNDgroundsingle_source
OEM-2-CPower groundgroundMICROSQUIRT-A-22 + MICROSQUIRT-A-23POWER GROUND + POWER GROUNDgroundsingle_source
OEM-2-DPower groundgroundMICROSQUIRT-A-22 + MICROSQUIRT-A-23POWER GROUND + POWER GROUNDgroundsingle_source
OEM-2-ECrank position (CAS NE)trigger_inMICROSQUIRT-A-32VR1+trigger_insingle_source
OEM-2-FAFM groundsensor_groundMICROSQUIRT-A-18 + MICROSQUIRT-A-19 + MICROSQUIRT-A-20Sensor Ground + Serial Ground + Sensor Groundsensor_groundsingle_source
OEM-2-GCam position (CAS G)trigger_inMICROSQUIRT-A-4VR2+trigger_insingle_source
OEM-2-ITachometer outputtacho_outMICROSQUIRT-A-35TACHOtacho_outsingle_source
OEM-2-K+5V sensor supplyvrefMICROSQUIRT-A-28TPS VREF (5V)vrefsingle_source
OEM-2-LIdle switch (TPS)digital_in———single_source
OEM-2-NO2 sensorlambda_nb_inMICROSQUIRT-A-34O2lambda_nb_insingle_source
OEM-2-OAir flow meter (AFM)analog_inMICROSQUIRT-A-5SPAREADC2 (MAF)analog_insingle_source
OEM-2-PIntake air temperature (IAT)temp_inMICROSQUIRT-A-26MATtemp_insingle_source
OEM-2-QCoolant temperature (ECT)temp_inMICROSQUIRT-A-25CLTtemp_insingle_source
OEM-2-UInjector 1injector_outMICROSQUIRT-A-9INJ 1injector_outsingle_source
OEM-2-VInjector 2injector_outMICROSQUIRT-A-10INJ 2injector_outsingle_source
OEM-2-YInjector 3injector_out———single_source
OEM-2-ZInjector 4injector_out———single_source

Cut list

WireFromToGauge (mm²)ColourLengthSignalIdent
W1OEM-1-BSP-14V-10.85no routeECU power +14V (main relay)—
W2SP-14V-1MICROSQUIRT-A-10.85no route+12V In—
W3OEM-2-ASP-GND-10.85no routePower ground—
W4OEM-2-BSP-GND-10.85no routePower ground—
W5OEM-2-CSP-GND-10.85no routePower ground—
W6OEM-2-DSP-GND-10.85no routePower ground—
W7SP-GND-1MICROSQUIRT-A-220.85no routePOWER GROUND—
W8SP-GND-1MICROSQUIRT-A-230.85no routePOWER GROUND—
W9OEM-2-FSP-0V-10.5no routeAFM ground—
W10SP-0V-1MICROSQUIRT-A-180.5no routeSensor Ground—
W11SP-0V-1MICROSQUIRT-A-190.5no routeSerial Ground—
W12SP-0V-1MICROSQUIRT-A-200.5no routeSensor Ground—
W13OEM-2-KMICROSQUIRT-A-280.5no route+5V sensor supply—
W14OEM-2-EMICROSQUIRT-A-320.5no routeCrank position (CAS NE)—
W15OEM-2-GMICROSQUIRT-A-40.5no routeCam position (CAS G)—
W16OEM-1-GMICROSQUIRT-A-110.5no routeIgnition 1 (coils 1+4, wasted spark)—
W17OEM-1-HMICROSQUIRT-A-120.5no routeIgnition 2 (coils 2+3, wasted spark)—
W18OEM-2-UMICROSQUIRT-A-90.5no routeInjector 1—
W19OEM-2-VMICROSQUIRT-A-100.5no routeInjector 2—
W20OEM-1-EMICROSQUIRT-A-160.5no routeMalfunction indicator lamp (MIL)—
W21OEM-2-IMICROSQUIRT-A-350.5no routeTachometer output—
W22OEM-2-OMICROSQUIRT-A-50.5no routeAir flow meter (AFM)—
W23OEM-2-NMICROSQUIRT-A-340.5no routeO2 sensor—
W24OEM-2-QMICROSQUIRT-A-250.5no routeCoolant temperature (ECT)—
W25OEM-2-PMICROSQUIRT-A-260.5no routeIntake air temperature (IAT)—
W26OEM-1-CMICROSQUIRT-A-300.5no routeStart signal—
W27OEM-1-NMICROSQUIRT-A-310.5no routeWide-open throttle switch—
W28OEM-1-PMICROSQUIRT-A-60.5no routePower steering pressure switch—
W29OEM-1-QMICROSQUIRT-A-290.5no routeA/C request—

Bill of materials

CategoryPart numberManufacturerDescriptionQtyUnit
connector174515-6TEAMP Multilock .040/.070 hybrid 22-pin female harness plug (Miata NA/NB ECU)1.000ea
connector174516-6TEAMP Multilock .040/.070 hybrid 26-pin female harness plug (Miata NA/NB ECU)1.000ea

ECU setup sheet

RoleEngine refEngine signalSensorECU pointECU functionECU classSetup flag
No configured channels.

Findings

Open (4)

SeverityCodeSubjectMessage
errorREQUIRED_UNMAPPEDOEM-2-YRequired OEM function "Injector 3" (injector_out) is not connected to the new ECU.
errorREQUIRED_UNMAPPEDOEM-2-ZRequired OEM function "Injector 4" (injector_out) is not connected to the new ECU.
warnNET_FAMILYOEM-1-Q ↔ MICROSQUIRT-A-29OEM-1-Q "A/C request" [digital_in] is wired to MICROSQUIRT-A-29 "SPAREADC" [analog_in]. Analog and digital on one net. A switch on an analog input works with a pull-up and a threshold; an analog sensor on a digital input loses its value.
infoUNMAPPEDOEM2 optional OEM pins are not mapped: OEM-1-V Neutral/clutch switch; OEM-2-L Idle switch (TPS)

Accepted (1)

CodeSubjectReasonBy
REQUIRED_UNMAPPEDOEM-1-ABattery-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 2026-10-06. Review every wire against both manuals before building. Open items: - OEM-2 Y: Injector 3: no free injector output on AMP EFI Microsquirt - OEM-2 Z: Injector 4: no free injector output on AMP EFI Microsquirt Not wired: - OEM-1 A: Constant +12V: AMP EFI Microsquirt has no battery-constant input; not needed - OEM-1 V: Neutral/clutch switch: no free switch_in/frequency_in/analog_0_5 on AMP EFI Microsquirt - OEM-2 L: Idle switch (TPS): no free switch_in/frequency_in/analog_0_5 on AMP EFI Microsquirt

Sources

ReliabilityKindTitleURLArchiveCapturedSHA-256
4vendor_docLink G4X MX5X install manual (NA 1.6/1.8)https://linkecu.com/documentation/MX5X.pdfarchive2026-10-05b7f730de9f6e
4vendor_docMSExtra: Microsquirt hardware 3.4http://www.msextra.com/doc/pdf/Microsquirt_Hardware-3.4.pdfarchive2026-10-05ad920d9160de