MicroSquirt V3 is a 35-pin wire-in MegaSquirt / AMP EFI ECU on 1 connector: AMPSEAL (35 pins).
It has 2 injector outputs and 2 ignition outputs. The injector drivers are saturated, which means high-impedance injectors. Low-impedance ones need a ballast resistor pack or a different ECU. The ignition outputs are logic-level. Smart coils plug straight in; dumb coils need an igniter in between.
There are 3 dedicated trigger inputs; the maker does not say which sensor type. There is no knock input. Wideband control needs an external controller, usually over CAN. MAP is an external sensor on an analog input.
The maker does not list drive-by-wire outputs. One CAN bus handles dashes, PDMs and expansion.
Spec sheet
| Connectors | AMPSEAL (35)35 pins in this profile |
|---|---|
| Injector outputs | 2saturated (high-impedance only) |
| Ignition outputs | 2logic-level: smart coils, or an igniter for dumb coils |
| Dedicated trigger inputs | 3sensor type not stated |
| Knock inputs | 0 |
| Onboard wideband controllers | 0 |
| Onboard MAP sensor | No |
| CAN buses | 1 |
| Drive-by-wire | Not stated by the maker |
| High-side outputs | 0 |
| Half-bridge outputs | 0 |
| 5V sensor supply | 1 pin |
Worth knowing
- Knock needs an external knock interface; the ECU has no native knock input.
Which builds it suits
Of the 58 swap presets in the planner, 0 fit as they are and 0 fit with add-ons; 58 do not fit at all. Where it falls short, it is usually not enough injector output (low-side). The planner fills anything a preset leaves open with its ordinary defaults, so your own build may land differently.
It can't run the Toyota 2JZ-GE distributor (NA, early): not enough injector output (low-side). It can't run the Ford Modular 4.6 4V Terminator (S/C, cable): not enough injector output (low-side). It can't run the Honda K20 (i-VTEC 2.0 NA): not enough injector output (low-side).
Does not fit 58
- Toyota 1JZ-GE distributor (NA, early) not enough injector output (low-side)
- Toyota 1JZ-GE VVT-i (coil pack) not enough injector output (low-side)
- Toyota 1JZ-GTE non-VVTi not enough injector output (low-side)
- Toyota 1JZ-GTE VVTi not enough injector output (low-side)
- Toyota 2JZ-GE distributor (NA, early) not enough injector output (low-side)
- Toyota 2JZ-GE VVT-i (coil pack) not enough injector output (low-side)
- Toyota 2JZ-GTE non-VVTi not enough injector output (low-side)
- Toyota 2JZ-GTE VVTi not enough injector output (low-side)
- GM LS1 (Gen3 5.7 alum) not enough injector output (low-side)
- GM LS6 (Gen3 5.7 alum) not enough injector output (low-side)
- GM LS LQ4/LQ9 (Gen3 6.0 iron) not enough injector output (low-side)
- GM LS2 (Gen4 6.0 alum) not enough injector output (low-side)
- GM LS3 (Gen4 6.2 alum, car) not enough injector output (low-side)
- GM LS L76 (Gen4 6.0 alum) not enough injector output (low-side)
- GM LS L92 (Gen4 6.2 alum) not enough injector output (low-side)
- GM LS LY6/L96 (Gen4 6.0 iron) not enough injector output (low-side)
- GM LSA (Gen4 6.2 alum, S/C) not enough injector output (low-side)
- GM LT1 (Gen5 6.2 alum) not enough injector output (low-side)
- GM LT4 (Gen5 6.2 alum, S/C) not enough injector output (low-side)
- Ford Coyote 5.0 Gen1 (2011-14) not enough injector output (low-side)
- Ford Coyote 5.0 Gen2 (2015-17) not enough injector output (low-side)
- Ford Coyote 5.0 Gen3 (2018-23) not enough injector output (low-side)
- Ford Modular 4.6 2V (SOHC) not enough injector output (low-side)
- Ford Modular 4.6 4V Cobra (NA, cable) not enough injector output (low-side)
- Ford Modular 4.6 4V Terminator (S/C, cable) not enough injector output (low-side)
- Ford Modular 5.4 4V Ford GT (S/C, cable) not enough injector output (low-side)
- Ford Modular 5.4 4V GT500 (S/C, DBW) not enough injector output (low-side)
- Ford Coyote Voodoo 5.2 (GT350, flat-plane) not enough injector output (low-side)
- Ford Coyote Predator 5.2 (GT500, cross-plane, S/C) not enough injector output (low-side)
- Ford Barra 4.0 NA (182/190/195) not enough injector output (low-side)
- Ford Barra 4.0 Turbo (240T/245T/270T/310T/325T) not enough injector output (low-side)
- Nissan RB20DET not enough injector output (low-side)
- Nissan RB25DET non-Neo S1 (R33, dumb coils) not enough injector output (low-side)
- Nissan RB25DET non-Neo S2 (R33, smart coils) not enough injector output (low-side)
- Nissan RB25DET Neo (R34) not enough injector output (low-side)
- Nissan RB26DETT (R32/R33, dumb coils) not enough injector output (low-side)
- Nissan RB26DETT (R34, smart coils) not enough injector output (low-side)
- Nissan VR38DETT (R35 GT-R) not enough injector output (low-side)
- Nissan SR20DET (S13) not enough injector output (low-side)
- Nissan SR20DET (S14) not enough injector output (low-side)
- Nissan SR20DET (S15) not enough injector output (low-side)
- Nissan VQ35DE (base, 2003-04) not enough injector output (low-side)
- Nissan VQ35DE Rev-Up (2005-06) not enough injector output (low-side)
- Nissan VQ35HR (High-Rev, 2007+) not enough injector output (low-side)
- Honda K20 (i-VTEC 2.0 NA) not enough injector output (low-side)
- Honda K24 (i-VTEC 2.4 NA) not enough injector output (low-side)
- Subaru EJ/FA EJ20 turbo single-AVCS (EJ207 v7-9) not enough injector output (low-side)
- Subaru EJ/FA EJ20 turbo dual-AVCS (EJ207 GRB 2008+) not enough injector output (low-side)
- Subaru EJ/FA EJ25 turbo single-AVCS (EJ257 2004-07) not enough injector output (low-side)
- Subaru EJ/FA EJ25 turbo dual-AVCS (EJ257 2008+) not enough injector output (low-side)
- Subaru EJ/FA FA20D (BRZ/86 NA) not enough injector output (low-side)
- Subaru EJ/FA FA20DIT (WRX turbo 2015+) not enough injector output (low-side)
- Mazda Rotary 13B-REW (FD RX-7) not enough ignition outputs
- Mazda Rotary 13B-MSP Renesis (RX-8 manual, 6-injector) not enough ignition outputs
- Mazda Rotary 13B-MSP Renesis (RX-8 auto, 4-injector) not enough ignition outputs
- Mazda Rotary 20B (Eunos Cosmo 3-rotor) not enough ignition outputs
- BMW S54 (3.2 NA I6, E46 M3) not enough injector output (low-side)
- BMW N54 (3.0 twin-turbo I6) not enough injector output (low-side)
Plan a build around the MicroSquirt V3
Pin table
Connector AMPSEAL carries 2 injector outputs, 2 ignition outputs and 3 trigger inputs.
Show all 35 pins
| Pin | Function |
|---|---|
| AMPSEAL 1 | 12 Volt Supply (switched) |
| AMPSEAL 2 | CAN High |
| AMPSEAL 3 | CAN Low |
| AMPSEAL 4 | VRIN2+ (2nd ignition input; VR or Hall cam/second sensor) |
| AMPSEAL 5 | Spare Input 2 (ADC7; alt MAF or knock) |
| AMPSEAL 6 | Flex Fuel |
| AMPSEAL 7 | FIDLE (on/off or PWM idle out) |
| AMPSEAL 8 | Fuel Pump (relay ground) |
| AMPSEAL 9 | Injector 1 (bank) |
| AMPSEAL 10 | Injector 2 (bank) |
| AMPSEAL 11 | Ignition Output #2 (logic level) |
| AMPSEAL 12 | Ignition Output #1 (logic level) |
| AMPSEAL 13 | Serial Rx |
| AMPSEAL 14 | Serial Tx |
| AMPSEAL 15 | Bootloader (ground to enter bootloader) |
| AMPSEAL 16 | Accel LED (or spare port) |
| AMPSEAL 17 | Warm-Up LED (or spare port) |
| AMPSEAL 18 | 2nd Sensor Ground |
| AMPSEAL 19 | Serial Ground |
| AMPSEAL 20 | Sensor Ground |
| AMPSEAL 21 | VR2IN- (return for 2nd VR/Hall input) |
| AMPSEAL 22 | Ground |
| AMPSEAL 23 | Ground |
| AMPSEAL 24 | MAP |
| AMPSEAL 25 | CLT |
| AMPSEAL 26 | IAT |
| AMPSEAL 27 | TPS |
| AMPSEAL 28 | Vref (+5V reference) |
| AMPSEAL 29 | Spare Input 1 (ext baro) |
| AMPSEAL 30 | OPTOIN+ (opto/Hall ignition input 1) |
| AMPSEAL 31 | OPTOIN- (opto input 1 return) |
| AMPSEAL 32 | VRIN1+ (VR ignition input 1) |
| AMPSEAL 33 | VRIN1- (VR input 1 return) |
| AMPSEAL 34 | O2 |
| AMPSEAL 35 | Tach Output |
Other MegaSquirt / AMP EFI ECUs
The closest MegaSquirt / AMP EFI unit is the MS3Pro Ultimate. Against it, this one has 2 injector outputs (the MS3Pro Ultimate has 10), 2 ignition outputs (the MS3Pro Ultimate has 8), 0 knock inputs (the MS3Pro Ultimate has 2) and 35 pins (the MS3Pro Ultimate has 93).
Source: MegaSquirt / AMP EFI documentation for the MicroSquirt V3
Always verify against the manufacturer's manual and your tuner before wiring.