Which ECU for the Mazda MX-5 Miata NA6 1990-93 (B6-ZE, 1.6)?
Every ECU below has a harness for this car. They all run the engine basics; the difference is how many of the stock ECU's other functions each one can still wire, and how much spare I/O is left for add-ons such as boost control or a wideband. “Of 23” counts the stock functions at least one ECU here wires.
Most complete
AMP EFI MS3Pro Ultimate
Can carry 23 of 23 stock functions, with 26 spare outputs and 17 spare inputs left.
Smallest that keeps every engine function
MaxxECU SPORT REV9+
48 ECU pins. Gives up 1 non-engine functions: power.
Most room for add-ons
MaxxECU PRO REV10+
52 spare outputs and 28 spare inputs after the stock wiring, with every engine function kept.
“Smallest” is by pin count, not price. Picks come from harnesses with no validation errors.
What each ECU wires and gives up
AMP EFI MS3Pro Ultimate93 pins · proposal
23/23Gives up nothing26 out · 17 inDetails ▾Gives up (no free pin on this ECU)
Nothing that another ECU wires for this car.
Emtron Shadow 868 pins · draft · 1 error
23/23Gives up nothing20 out · 14 inDetails ▾Gives up (no free pin on this ECU)
Nothing that another ECU wires for this car.
MaxxECU PRO REV10+155 pins · proposal
22/23Power 152 out · 28 inDetails ▾Gives up (no free pin on this ECU)
Power
Memory (battery-constant) feed. Only needed by ECUs with a keep-alive input.
- Constant +12V
MoTeC M190 13190136 pins · proposal
22/23Dash & gauges 145 out · 32 inDetails ▾Gives up (no free pin on this ECU)
Dash & gauges
Gauge and warning-light drives. The cluster may lose a gauge or a light.
- Tachometer output
Emtron KV16120 pins · proposal
22/23Power 140 out · 25 inDetails ▾Gives up (no free pin on this ECU)
Power
Memory (battery-constant) feed. Only needed by ECUs with a keep-alive input.
- Constant +12V
MoTeC M150 13150120 pins · proposal
22/23Dash & gauges 133 out · 32 inDetails ▾Gives up (no free pin on this ECU)
Dash & gauges
Gauge and warning-light drives. The cluster may lose a gauge or a light.
- Tachometer output
Emtron KV12115 pins · proposal
22/23Power 136 out · 25 inDetails ▾Gives up (no free pin on this ECU)
Power
Memory (battery-constant) feed. Only needed by ECUs with a keep-alive input.
- Constant +12V
MaxxECU GEN2 RACE136 pins · proposal
22/23Power 136 out · 23 inDetails ▾Gives up (no free pin on this ECU)
Power
Memory (battery-constant) feed. Only needed by ECUs with a keep-alive input.
- Constant +12V
Emtron KV8106 pins · proposal
22/23Power 128 out · 25 inDetails ▾Gives up (no free pin on this ECU)
Power
Memory (battery-constant) feed. Only needed by ECUs with a keep-alive input.
- Constant +12V
rusEFI Proteus93 pins · proposal
22/23Power 130 out · 15 inDetails ▾Gives up (no free pin on this ECU)
Power
Memory (battery-constant) feed. Only needed by ECUs with a keep-alive input.
- Constant +12V
AMP EFI MS3Pro EVO+89 pins · proposal
22/23Power 126 out · 17 inDetails ▾Gives up (no free pin on this ECU)
Power
Memory (battery-constant) feed. Only needed by ECUs with a keep-alive input.
- Constant +12V
AMP EFI MS3Pro EVO+ HC89 pins · proposal
22/23Power 126 out · 17 inDetails ▾Gives up (no free pin on this ECU)
Power
Memory (battery-constant) feed. Only needed by ECUs with a keep-alive input.
- Constant +12V
MaxxECU GEN2 TRACK93 pins · proposal
22/23Power 124 out · 13 inDetails ▾Gives up (no free pin on this ECU)
Power
Memory (battery-constant) feed. Only needed by ECUs with a keep-alive input.
- Constant +12V
Link G4X XtremeX 109-400067 pins · draft
22/23Power 118 out · 15 inDetails ▾Gives up (no free pin on this ECU)
Power
Memory (battery-constant) feed. Only needed by ECUs with a keep-alive input.
- Constant +12V
Emtron SL866 pins · proposal
22/23Power 119 out · 11 inDetails ▾Gives up (no free pin on this ECU)
Power
Memory (battery-constant) feed. Only needed by ECUs with a keep-alive input.
- Constant +12V
Link G4X FuryX 122-400068 pins · draft
22/23Power 117 out · 13 inDetails ▾Gives up (no free pin on this ECU)
Power
Memory (battery-constant) feed. Only needed by ECUs with a keep-alive input.
- Constant +12V
Haltech Nexus S3 HT-21300068 pins · proposal
22/23Power 120 out · 10 inDetails ▾Gives up (no free pin on this ECU)
Power
Memory (battery-constant) feed. Only needed by ECUs with a keep-alive input.
- Constant +12V
MaxxECU RACE REV9+80 pins · proposal
22/23Power 123 out · 7 inDetails ▾Gives up (no free pin on this ECU)
Power
Memory (battery-constant) feed. Only needed by ECUs with a keep-alive input.
- Constant +12V
Link G4X StormX 108-400060 pins · draft
22/23Power 116 out · 11 inDetails ▾Gives up (no free pin on this ECU)
Power
Memory (battery-constant) feed. Only needed by ECUs with a keep-alive input.
- Constant +12V
Haltech Elite 2500 HT-15130060 pins · proposal
22/23Power 120 out · 7 inDetails ▾Gives up (no free pin on this ECU)
Power
Memory (battery-constant) feed. Only needed by ECUs with a keep-alive input.
- Constant +12V
MoTeC M170 1317066 pins · proposal
22/23Dash & gauges 117 out · 10 inDetails ▾Gives up (no free pin on this ECU)
Dash & gauges
Gauge and warning-light drives. The cluster may lose a gauge or a light.
- Tachometer output
MoTeC M130 1313060 pins · proposal
22/23Dash & gauges 117 out · 9 inDetails ▾Gives up (no free pin on this ECU)
Dash & gauges
Gauge and warning-light drives. The cluster may lose a gauge or a light.
- Tachometer output
Emtron SL662 pins · proposal
22/23Power 115 out · 11 inDetails ▾Gives up (no free pin on this ECU)
Power
Memory (battery-constant) feed. Only needed by ECUs with a keep-alive input.
- Constant +12V
ECUMASTER EMU Black63 pins · proposal
22/23Power 115 out · 8 inDetails ▾Gives up (no free pin on this ECU)
Power
Memory (battery-constant) feed. Only needed by ECUs with a keep-alive input.
- Constant +12V
Emtron SL458 pins · proposal
22/23Power 111 out · 11 inDetails ▾Gives up (no free pin on this ECU)
Power
Memory (battery-constant) feed. Only needed by ECUs with a keep-alive input.
- Constant +12V
MoTeC M800 universal60 pins · proposal
22/23Power 114 out · 8 inDetails ▾Gives up (no free pin on this ECU)
Power
Memory (battery-constant) feed. Only needed by ECUs with a keep-alive input.
- Constant +12V
Haltech Elite 1500 HT-15090051 pins · proposal
22/23Power 112 out · 6 inDetails ▾Gives up (no free pin on this ECU)
Power
Memory (battery-constant) feed. Only needed by ECUs with a keep-alive input.
- Constant +12V
MaxxECU SPORT REV9+48 pins · proposal
22/23Power 113 out · 3 inDetails ▾Gives up (no free pin on this ECU)
Power
Memory (battery-constant) feed. Only needed by ECUs with a keep-alive input.
- Constant +12V
ECUMASTER EMU PRO 16120 pins · draft · 1 error
21/23Engine 1Power 142 out · 28 inDetails ▾Gives up (no free pin on this ECU)
Engine
Engine sensors and actuators (fuel, spark, triggers, cam/valve control). Check whether the new ECU needs each one: a second cam sensor, for example, is often optional, a VTEC or VVT solenoid is not.
- Cam position (CAS G)
Power
Memory (battery-constant) feed. Only needed by ECUs with a keep-alive input.
- Constant +12V
Link G4X MonsoonX34 pins · draft
21/23Engine 1Power 16 out · 1 inDetails ▾Gives up (no free pin on this ECU)
Engine
Engine sensors and actuators (fuel, spark, triggers, cam/valve control). Check whether the new ECU needs each one: a second cam sensor, for example, is often optional, a VTEC or VVT solenoid is not.
- Idle switch (TPS)
Power
Memory (battery-constant) feed. Only needed by ECUs with a keep-alive input.
- Constant +12V
AMP EFI MS3Pro Mini35 pins · proposal
20/23Engine 1Dash & gauges 1Power 17 out · 3 inDetails ▾Gives up (no free pin on this ECU)
Engine
Engine sensors and actuators (fuel, spark, triggers, cam/valve control). Check whether the new ECU needs each one: a second cam sensor, for example, is often optional, a VTEC or VVT solenoid is not.
- Idle switch (TPS)
Dash & gauges
Gauge and warning-light drives. The cluster may lose a gauge or a light.
- Tachometer output
Power
Memory (battery-constant) feed. Only needed by ECUs with a keep-alive input.
- Constant +12V
Link G4X AtomX 111-400030 pins · draft
19/23Engine 1Idle & accessories 2Power 14 out · 1 inDetails ▾Gives up (no free pin on this ECU)
Engine
Engine sensors and actuators (fuel, spark, triggers, cam/valve control). Check whether the new ECU needs each one: a second cam sensor, for example, is often optional, a VTEC or VVT solenoid is not.
- Idle switch (TPS)
Idle & accessories
Electrical load, A/C, fans, switches. Tune idle around them, or wire them to spare I/O later.
- A/C request
- Neutral/clutch switch
Power
Memory (battery-constant) feed. Only needed by ECUs with a keep-alive input.
- Constant +12V
MaxxECU STREET REV9+40 pins · proposal
18/23Engine 1Idle & accessories 3Power 19 out · 3 inDetails ▾Gives up (no free pin on this ECU)
Engine
Engine sensors and actuators (fuel, spark, triggers, cam/valve control). Check whether the new ECU needs each one: a second cam sensor, for example, is often optional, a VTEC or VVT solenoid is not.
- Idle switch (TPS)
Idle & accessories
Electrical load, A/C, fans, switches. Tune idle around them, or wire them to spare I/O later.
- A/C request
- Neutral/clutch switch
- Power steering pressure switch
Power
Memory (battery-constant) feed. Only needed by ECUs with a keep-alive input.
- Constant +12V
AMP EFI Microsquirt35 pins · draft · 2 errors
18/23Engine 3Idle & accessories 1Power 13 out · 4 inDetails ▾Gives up (no free pin on this ECU)
Engine
Engine sensors and actuators (fuel, spark, triggers, cam/valve control). Check whether the new ECU needs each one: a second cam sensor, for example, is often optional, a VTEC or VVT solenoid is not.
- Idle switch (TPS)
- Injector 3
- Injector 4
Idle & accessories
Electrical load, A/C, fans, switches. Tune idle around them, or wire them to spare I/O later.
- Neutral/clutch switch
Power
Memory (battery-constant) feed. Only needed by ECUs with a keep-alive input.
- Constant +12V
Speeduino v0.436 pins · draft · 1 error
17/23Engine 1Idle & accessories 3Dash & gauges 1Power 111 out · 4 inDetails ▾Gives up (no free pin on this ECU)
Engine
Engine sensors and actuators (fuel, spark, triggers, cam/valve control). Check whether the new ECU needs each one: a second cam sensor, for example, is often optional, a VTEC or VVT solenoid is not.
- Idle switch (TPS)
Idle & accessories
Electrical load, A/C, fans, switches. Tune idle around them, or wire them to spare I/O later.
- A/C request
- Neutral/clutch switch
- Power steering pressure switch
Dash & gauges
Gauge and warning-light drives. The cluster may lose a gauge or a light.
- Air flow meter (AFM)
Power
Memory (battery-constant) feed. Only needed by ECUs with a keep-alive input.
- Constant +12V
MaxxECU MINI REV10+30 pins · draft · 1 error
17/23Engine 2Idle & accessories 3Power 14 out · 1 inDetails ▾Gives up (no free pin on this ECU)
Engine
Engine sensors and actuators (fuel, spark, triggers, cam/valve control). Check whether the new ECU needs each one: a second cam sensor, for example, is often optional, a VTEC or VVT solenoid is not.
- Cam position (CAS G)
- Idle switch (TPS)
Idle & accessories
Electrical load, A/C, fans, switches. Tune idle around them, or wire them to spare I/O later.
- A/C request
- Neutral/clutch switch
- Power steering pressure switch
Power
Memory (battery-constant) feed. Only needed by ECUs with a keep-alive input.
- Constant +12V
ECUs without a harness for this car
- AMP EFI AMP PNP Miata NA6Plug-inPlug-in: mates the stock plugs pin-for-pin, no adapter harness
- Link MX5NAXPlug-inPlug-in: mates the stock plugs pin-for-pin, no adapter harness
- AEM EMS 30-1042Not suitable · discontinuedPlug-in for Honda NSX NA1 1991-2005 (C30A) only; this car's stock plugs differ
- AMP EFI AMP PNP Miata NA8 94-95Not suitablePlug-in for MX-5 Miata NA8 1994-97 (BP-ZE, 1.8) only; this car's stock plugs differ
- AMP EFI AMP PNP Miata NA8 96-97Not suitablePlug-in for MX-5 Miata NA8 1994-97 (BP-ZE, 1.8) only; this car's stock plugs differ
- AMP EFI AMP PNP Miata NB1Not suitablePlug-in for MX-5 Miata NB1 1999-00 (BP-4W) only; this car's stock plugs differ
- AMP EFI AMP PNP Miata NB2Not suitablePlug-in for MX-5 Miata NB2 2001-05 (BP-Z3, VVT) only; this car's stock plugs differ
- MaxxECU C6 E38 Plug-inNot suitablePlug-in for Chevrolet Corvette C6 2005-13 (LS2/LS3/LS7) only; this car's stock plugs differ
- Link CIVICLink K20XNot suitablePlug-in for RSX Type-S 2002-04 (K20A2) only; this car's stock plugs differ
- Link E36XNot suitablePlug-in for BMW 3 Series E36 1990–2000 (M50/M52) only; this car's stock plugs differ
- Haltech Elite 1500 HT-140960 (02-04 RSX PnP)Not suitablePlug-in for RSX Type-S 2002-04 (K20A2) only; this car's stock plugs differ
- Haltech Elite 1500 HT-140961 (05-06 RSX PnP)Not suitablePlug-in for RSX Type-S 2005-06 (K20Z1) only; this car's stock plugs differ
- ECUMASTER EMU Black PnP ECU2JZBNot suitablePlug-in for Toyota Supra A80 1993-98 USDM (2JZ-GTE, non-VVT) only; this car's stock plugs differ
- ECUMASTER EMU Black PnP K20A2Not suitablePlug-in for RSX Type-S 2002-04 (K20A2) only; this car's stock plugs differ
- Hondata FlashProNot suitablePlug-in for AP2 2006–09 (F22C1, DBW) only; this car's stock plugs differ
- Link G4X S2000XNot suitablePlug-in for AP1 2000–03 (F20C), AP2 2004–05 (F22C1, cable) only; this car's stock plugs differ
- rusEFI Hellen 125 Honda KNot suitablePlug-in for RSX Type-S 2002-04 (K20A2) only; this car's stock plugs differ
- Hondata KPro4Not suitablePlug-in for RSX Type-S 2002-04 (K20A2) only; this car's stock plugs differ
- MaxxECU Mustang 2011-14 plug-inNot suitablePlug-in for Mustang GT 2011–14 (Coyote 5.0) only; this car's stock plugs differ
- Link MX5NB1XNot suitablePlug-in for MX-5 Miata NB1 1999-00 (BP-4W) only; this car's stock plugs differ
- Link MX5NB2XNot suitablePlug-in for MX-5 Miata NB2 2001-05 (BP-Z3, VVT) only; this car's stock plugs differ
- Link RX7XNot suitablePlug-in for Mazda RX-7 FD 1992-2002 (13B-REW twin-turbo) only; this car's stock plugs differ
- Link SupraLinkNot suitablePlug-in for Toyota Supra A80 1993-98 USDM (2JZ-GTE, non-VVT) only; this car's stock plugs differ
- Holley Terminator X MAXNot suitableSold only as V8 engine kits (LS, Hemi, Ford) with fixed trigger patterns; no Subaru, Honda or Mazda support found
Categories are read from the stock pin names and are a guide; each item shows its full stock name. Power and ground pins aren't compared, since every harness powers and grounds the ECU. Prices aren't considered. Always check the harness's own findings before building.