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MX-5 Miata NB1 1999-00 (BP-4W) → AMP EFI Microsquirt (auto)

MX-5 Miata NB1 1999-00 (BP-4W) — AMP EFI — Microsquirt
⚠ NOT CHECKED. Don't build from this.
Drawn by Michael Gnankou · Rev 0 · draft · 2026-10-04

Revisions

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No revisions yet.

Schematic

MICROSQUIRT-AOEM-1OEM-2OEM-3SP-0VSP-14VSP-GND

Connectors

MICROSQUIRT-A

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1+12V In—W3—0.85SP-14V-1———
10INJ 2—W19—0.5OEM-3-X———
11SPK B (IGN2)—W16—0.5OEM-3-G———
12SPK A (IGN 1)—W17—0.5OEM-3-H———
13RX————————
14TX————————
15BOOT LOAD————————
16ALED—W21—0.5OEM-1-R———
17WLED—W22—0.5OEM-1-S———
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—W29—0.5OEM-2-E———
26MAT—W30—0.5OEM-2-B———
27TPS—W26—0.5OEM-3-E———
28TPS VREF (5V)—W13—0.5OEM-2-I———
29SPAREADC—W28—0.5OEM-3-J———
3CANL————————
30OPTO+—W31—0.5OEM-2-D———
31OPTO-—W32—0.5OEM-1-F———
32VR1+—W14—0.5OEM-2-J———
33VR1-————————
34O2—W27—0.5OEM-2-C———
35TACHO—W24—0.5OEM-2-K———
4VR2+—W15—0.5OEM-2-H———
5SPAREADC2 (MAF)—W25—0.5OEM-2-L———
6FLEX—W33—0.5OEM-1-G———
7FIDLE—W23—0.5OEM-3-N———
8FP (pump)—W20—0.5OEM-1-I———
9INJ 1—W18—0.5OEM-3-W———

OEM-1

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
AConstant +12V————————
BECU power +14V (main relay)—W1—0.85SP-14V-1———
EMalfunction indicator lamp (MIL)————————
FBrake switch—W32—0.5MICROSQUIRT-A-31———
GPower steering pressure switch—W33—0.5MICROSQUIRT-A-6———
ICondenser fan relay—W20—0.5MICROSQUIRT-A-8———
OAlternator control————————
PA/C request————————
QCharge lamp————————
RCooling fan relay—W21—0.5MICROSQUIRT-A-16———
SA/C clutch relay—W22—0.5MICROSQUIRT-A-17———
UFront O2 heater————————
VNeutral switch————————

OEM-2

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
AFuel tank pressure————————
BIntake air temperature (IAT)—W30—0.5MICROSQUIRT-A-26———
CFront O2 signal—W27—0.5MICROSQUIRT-A-34———
DVehicle speed—W31—0.5MICROSQUIRT-A-30———
ECoolant temperature (ECT)—W29—0.5MICROSQUIRT-A-25———
FKnock sensor————————
HCam position (CMP)—W15—0.5MICROSQUIRT-A-4———
I+5V sensor supply—W13—0.5MICROSQUIRT-A-28———
JCrank position (CKP)—W14—0.5MICROSQUIRT-A-32———
KTachometer output—W24—0.5MICROSQUIRT-A-35———
LMass air flow (MAF)—W25—0.5MICROSQUIRT-A-5———
MEGR valve————————
NEGR valve————————
OEGR valve————————
PEGR valve————————

OEM-3

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
APower ground—W4—0.85SP-GND-1———
BPower ground—W5—0.85SP-GND-1———
CPower ground—W6—0.85SP-GND-1———
EThrottle position (TPS)—W26—0.5MICROSQUIRT-A-27———
FSignal ground—W9—0.5SP-0V-1———
GIgnition 1 (coils 1+4, wasted spark)—W16—0.5MICROSQUIRT-A-11———
HIgnition 2 (coils 2+3, wasted spark)—W17—0.5MICROSQUIRT-A-12———
IClutch switch————————
JRear O2 signal—W28—0.5MICROSQUIRT-A-29———
KFuel level————————
LEvap purge solenoid————————
MISC valve +14V feed—W2—0.85SP-14V-1———
NFuel pump relay—W23—0.5MICROSQUIRT-A-7———
OISC valve low side————————
QVICS solenoid (intake butterflies)————————
SEGR boost sensor————————
TEGR boost solenoid————————
UCanister drain cut valve (CDCV)————————
VRear O2 heater————————
WInjector 1—W18—0.5MICROSQUIRT-A-9———
XInjector 2—W19—0.5MICROSQUIRT-A-10———
YInjector 3————————
ZInjector 4————————

SP-0V

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1——W9—0.5OEM-3-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—0.85OEM-3-M———
1——W3—0.85MICROSQUIRT-A-1———

SP-GND

CavityFunctionSignalWireColourGauge (mm²)DestinationTerminalSealPlug
1——W4—0.85OEM-3-A———
1——W5—0.85OEM-3-B———
1——W6—0.85OEM-3-C———
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-EMalfunction indicator lamp (MIL)low_side_out———single_source
OEM-1-FBrake switchdigital_inMICROSQUIRT-A-31OPTO-digital_insingle_source
OEM-1-GPower steering pressure switchdigital_inMICROSQUIRT-A-6FLEXdigital_insingle_source
OEM-1-ICondenser fan relaylow_side_outMICROSQUIRT-A-8FP (pump)low_side_outsingle_source
OEM-1-OAlternator controllow_side_out———single_source
OEM-1-PA/C requestdigital_in———single_source
OEM-1-QCharge lamplow_side_out———single_source
OEM-1-RCooling fan relaylow_side_outMICROSQUIRT-A-16ALEDlow_side_outsingle_source
OEM-1-SA/C clutch relaylow_side_outMICROSQUIRT-A-17WLEDlow_side_outsingle_source
OEM-1-UFront O2 heaterlow_side_out———single_source
OEM-1-VNeutral switchdigital_in———single_source
OEM-2-AFuel tank pressureanalog_in———single_source
OEM-2-BIntake air temperature (IAT)temp_inMICROSQUIRT-A-26MATtemp_insingle_source
OEM-2-CFront O2 signallambda_nb_inMICROSQUIRT-A-34O2lambda_nb_insingle_source
OEM-2-DVehicle speeddigital_inMICROSQUIRT-A-30OPTO+digital_insingle_source
OEM-2-ECoolant temperature (ECT)temp_inMICROSQUIRT-A-25CLTtemp_insingle_source
OEM-2-FKnock sensorknock_in———single_source
OEM-2-HCam position (CMP)trigger_inMICROSQUIRT-A-4VR2+trigger_insingle_source
OEM-2-I+5V sensor supplyvrefMICROSQUIRT-A-28TPS VREF (5V)vrefsingle_source
OEM-2-JCrank position (CKP)trigger_inMICROSQUIRT-A-32VR1+trigger_insingle_source
OEM-2-KTachometer outputtacho_outMICROSQUIRT-A-35TACHOtacho_outsingle_source
OEM-2-LMass air flow (MAF)analog_inMICROSQUIRT-A-5SPAREADC2 (MAF)analog_insingle_source
OEM-2-MEGR valvelow_side_out———single_source
OEM-2-NEGR valvelow_side_out———single_source
OEM-2-OEGR valvelow_side_out———single_source
OEM-2-PEGR valvelow_side_out———single_source
OEM-3-APower groundgroundMICROSQUIRT-A-22 + MICROSQUIRT-A-23POWER GROUND + POWER GROUNDgroundsingle_source
OEM-3-BPower groundgroundMICROSQUIRT-A-22 + MICROSQUIRT-A-23POWER GROUND + POWER GROUNDgroundsingle_source
OEM-3-CPower groundgroundMICROSQUIRT-A-22 + MICROSQUIRT-A-23POWER GROUND + POWER GROUNDgroundsingle_source
OEM-3-EThrottle position (TPS)analog_inMICROSQUIRT-A-27TPSanalog_insingle_source
OEM-3-FSignal groundsensor_groundMICROSQUIRT-A-18 + MICROSQUIRT-A-19 + MICROSQUIRT-A-20Sensor Ground + Serial Ground + Sensor Groundsensor_groundsingle_source
OEM-3-GIgnition 1 (coils 1+4, wasted spark)ignition_outMICROSQUIRT-A-11SPK B (IGN2)ignition_outsingle_source
OEM-3-HIgnition 2 (coils 2+3, wasted spark)ignition_outMICROSQUIRT-A-12SPK A (IGN 1)ignition_outsingle_source
OEM-3-IClutch switchdigital_in———single_source
OEM-3-JRear O2 signallambda_nb_inMICROSQUIRT-A-29SPAREADCanalog_insingle_source
OEM-3-KFuel levelanalog_in———single_source
OEM-3-LEvap purge solenoidlow_side_out———single_source
OEM-3-MISC valve +14V feedpower_inMICROSQUIRT-A-1+12V Inpower_insingle_source
OEM-3-NFuel pump relaylow_side_outMICROSQUIRT-A-7FIDLElow_side_outsingle_source
OEM-3-OISC valve low sidelow_side_out———single_source
OEM-3-QVICS solenoid (intake butterflies)low_side_out———single_source
OEM-3-SEGR boost sensoranalog_in———single_source
OEM-3-TEGR boost solenoidlow_side_out———single_source
OEM-3-UCanister drain cut valve (CDCV)low_side_out———single_source
OEM-3-VRear O2 heaterlow_side_out———single_source
OEM-3-WInjector 1injector_outMICROSQUIRT-A-9INJ 1injector_outsingle_source
OEM-3-XInjector 2injector_outMICROSQUIRT-A-10INJ 2injector_outsingle_source
OEM-3-YInjector 3injector_out———single_source
OEM-3-ZInjector 4injector_out———single_source

Cut list

WireFromToGauge (mm²)ColourLengthSignalIdent
W1OEM-1-BSP-14V-10.85no routeECU power +14V (main relay)—
W2OEM-3-MSP-14V-10.85no routeISC valve +14V feed—
W3SP-14V-1MICROSQUIRT-A-10.85no route+12V In—
W4OEM-3-ASP-GND-10.85no routePower ground—
W5OEM-3-BSP-GND-10.85no routePower ground—
W6OEM-3-CSP-GND-10.85no routePower ground—
W7SP-GND-1MICROSQUIRT-A-220.85no routePOWER GROUND—
W8SP-GND-1MICROSQUIRT-A-230.85no routePOWER GROUND—
W9OEM-3-FSP-0V-10.5no routeSignal 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-IMICROSQUIRT-A-280.5no route+5V sensor supply—
W14OEM-2-JMICROSQUIRT-A-320.5no routeCrank position (CKP)—
W15OEM-2-HMICROSQUIRT-A-40.5no routeCam position (CMP)—
W16OEM-3-GMICROSQUIRT-A-110.5no routeIgnition 1 (coils 1+4, wasted spark)—
W17OEM-3-HMICROSQUIRT-A-120.5no routeIgnition 2 (coils 2+3, wasted spark)—
W18OEM-3-WMICROSQUIRT-A-90.5no routeInjector 1—
W19OEM-3-XMICROSQUIRT-A-100.5no routeInjector 2—
W20OEM-1-IMICROSQUIRT-A-80.5no routeCondenser fan relay—
W21OEM-1-RMICROSQUIRT-A-160.5no routeCooling fan relay—
W22OEM-1-SMICROSQUIRT-A-170.5no routeA/C clutch relay—
W23OEM-3-NMICROSQUIRT-A-70.5no routeFuel pump relay—
W24OEM-2-KMICROSQUIRT-A-350.5no routeTachometer output—
W25OEM-2-LMICROSQUIRT-A-50.5no routeMass air flow (MAF)—
W26OEM-3-EMICROSQUIRT-A-270.5no routeThrottle position (TPS)—
W27OEM-2-CMICROSQUIRT-A-340.5no routeFront O2 signal—
W28OEM-3-JMICROSQUIRT-A-290.5no routeRear O2 signal—
W29OEM-2-EMICROSQUIRT-A-250.5no routeCoolant temperature (ECT)—
W30OEM-2-BMICROSQUIRT-A-260.5no routeIntake air temperature (IAT)—
W31OEM-2-DMICROSQUIRT-A-300.5no routeVehicle speed—
W32OEM-1-FMICROSQUIRT-A-310.5no routeBrake switch—
W33OEM-1-GMICROSQUIRT-A-60.5no routePower steering pressure switch—

Bill of materials

CategoryPart numberManufacturerDescriptionQtyUnit

ECU setup sheet

RoleEngine refEngine signalSensorECU pointECU functionECU classSetup flag
No configured channels.

Findings

Open (3)

SeverityCodeSubjectMessage
errorREQUIRED_UNMAPPEDOEM-3-YRequired OEM function "Injector 3" (injector_out) is not connected to the new ECU.
errorREQUIRED_UNMAPPEDOEM-3-ZRequired OEM function "Injector 4" (injector_out) is not connected to the new ECU.
infoUNMAPPEDOEM21 optional OEM pins are not mapped: OEM-1-E Malfunction indicator lamp (MIL); OEM-1-O Alternator control; OEM-1-P A/C request; OEM-1-Q Charge lamp; OEM-1-U Front O2 heater; OEM-1-V Neutral switch; OEM-2-A Fuel tank pressure; OEM-2-F Knock sensor; OEM-2-M EGR valve; OEM-2-N EGR valve; OEM-2-O EGR valve; OEM-2-P EGR valve; OEM-3-I Clutch switch; OEM-3-K Fuel level; OEM-3-L Evap purge solenoid; OEM-3-O ISC valve low side; OEM-3-Q VICS solenoid (intake butterflies); OEM-3-S EGR boost sensor; OEM-3-T EGR boost solenoid; OEM-3-U Canister drain cut valve (CDCV); OEM-3-V Rear O2 heater

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 2026-10-04. Review every wire against both manuals before building. Open items: - OEM-3 Y: Injector 3: no free injector output on AMP EFI Microsquirt - OEM-3 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-2 F: Knock sensor: no free knock input on AMP EFI Microsquirt - OEM-1 U: Front O2 heater: no free heater_low_side/low_side/ls_hs/hbridge on AMP EFI Microsquirt - OEM-3 V: Rear O2 heater: no free heater_low_side/low_side/ls_hs/hbridge on AMP EFI Microsquirt - OEM-3 O: ISC valve low side: no free low_side/ls_hs/injector/hbridge rated ≥ 1.0 A on AMP EFI Microsquirt - OEM-1 E: Malfunction indicator lamp (MIL): no free low_side/ls_hs/injector/hbridge on AMP EFI Microsquirt - OEM-1 O: Alternator control: no free low_side/ls_hs/injector/hbridge on AMP EFI Microsquirt - OEM-1 Q: Charge lamp: no free low_side/ls_hs/injector/hbridge on AMP EFI Microsquirt - OEM-2 M: EGR valve: no free low_side/ls_hs/injector/hbridge on AMP EFI Microsquirt - OEM-2 N: EGR valve: no free low_side/ls_hs/injector/hbridge on AMP EFI Microsquirt - OEM-2 O: EGR valve: no free low_side/ls_hs/injector/hbridge on AMP EFI Microsquirt - OEM-2 P: EGR valve: no free low_side/ls_hs/injector/hbridge on AMP EFI Microsquirt - OEM-3 L: Evap purge solenoid: no free low_side/ls_hs/injector/hbridge on AMP EFI Microsquirt - OEM-3 Q: VICS solenoid (intake butterflies): no free low_side/ls_hs/injector/hbridge on AMP EFI Microsquirt - OEM-3 T: EGR boost solenoid: no free low_side/ls_hs/injector/hbridge on AMP EFI Microsquirt - OEM-3 U: Canister drain cut valve (CDCV): no free low_side/ls_hs/injector/hbridge on AMP EFI Microsquirt - OEM-2 A: Fuel tank pressure: no free analog_0_5 on AMP EFI Microsquirt - OEM-3 K: Fuel level: no free analog_0_5 on AMP EFI Microsquirt - OEM-3 S: EGR boost sensor: no free analog_0_5 on AMP EFI Microsquirt - OEM-1 P: A/C request: no free switch_in/frequency_in/analog_0_5 on AMP EFI Microsquirt - OEM-1 V: Neutral switch: no free switch_in/frequency_in/analog_0_5 on AMP EFI Microsquirt - OEM-3 I: Clutch switch: no free switch_in/frequency_in/analog_0_5 on AMP EFI Microsquirt

Sources

ReliabilityKindTitleURL
4vendor_docLink G4X MX5NB1X install manual (NB1 1999-00)https://linkecu.com/documentation/MX5XNB1.pdf
4vendor_docMSExtra: Microsquirt hardware 3.4http://www.msextra.com/doc/pdf/Microsquirt_Hardware-3.4.pdf