MegaSquirt ECU Options

MegaSquirt-I PCBv2.2 – By default a fuel only controller.  Free MS1/Extra firmware allows full fuel and spark control and a ton of other features.  The V2.2 board doesn’t have as many parts for ignition control; it is relatively straightforward to set up with GM HEI, Ford EDIS or TFI, or the Hall effect distributors used on some Volvo and VW applications, but on more complicated ignition systems, it’s usually worth stepping up to a V3.0 or V3.57.  This is cheap and effective.  If you are running low-impedance injectors you should also pickup the Flyback board kit’ as an upgrade to the unit.  Kit is $153, flyback upgrade kit is $27.  Assembled units w/o flyback upgrade are $252.

MegaSquirt-I PCBv3.0 – By default a fuel only controller.  Free MS1/Extra firmware allows full fuel and spark control and a ton of other features.  This unit is affordable, feature packed, and works great.  Has several upgrades making the unit more robust and harder to damage with a wiring mistake.  Also has circuitry to directly drive a coil without an external ignitor (with MSnS-E), plus input for a variable reluctor sensor (what MSD calls a magnetic pickup).  No upgrade needed for low-z injectors.  Kit is $203.  Assembled units are $346.

MegaSquirt-II PCBv3.0 – Upgrading the processor gives lots of new and improved, features including a finer degree of fuel control (great for tuning idle with large injectors) and native ignition control.  This is an affordable and feature packed unit that was just recently released and will be further developed to add more and more features over time.  As this is based on the PCB3.0, it also has several upgrades making the unit more robust and harder to damage with a wiring mistake.  Also has circuitry to directly drive a coil without an external ignitor.  No upgrade needed for low-z injectors.  Kit is $266.  Assembled units are $420.

MegaSquirt-I PCBv3.57 – A surface mount version of the V3.0. By default a fuel only controller.  Free MS1/Extra firmware allows full fuel and spark control and a ton of other features.  This unit is affordable, feature packed, and works great.  This one adds PWM idle control and a DB15 connector for adding MSnS-E upgrades.  Has several upgrades making the unit more robust and harder to damage with a wiring mistake, and easily switched jumpers allowing quick reconfiguration for Hall or VR input.  Also has circuitry to directly drive a coil without an external ignitor (with MSnS-E).  No upgrade needed for low-z injectors. These do not come in kit form.  Assembled units are $358.

MegaSquirt-II PCBv3.57 – A machine assembled version of the MS2 V3.0, with the same upgrades over MS1, including a finer degree of fuel control (great for tuning idle with large injectors) and native ignition control.  This one adds PWM idle control and a DB15 connector for adding MS2/Extra upgrades.  Also has circuitry to directly drive a coil without an external ignitor available as an option.  No upgrade needed for low-z injectors. These only come in assembled form. Assembled units are $432.

MegaSquirt-III PCBv3.0 – This one takes the MS2 concept a step further, with an even more powerful processor that also adds onboard SD card logging and USB communication.  But perhaps its biggest draw is the MS3X expansion board, which you can add for eight channel sequential fuel and eight channel ignition control, plus tach output, boost control output, nitrous control, and more.  Kit is $365.  MS3X expansion board is $90.

MegaSquirt-III PCBv3.57 – A machine assembled MS3, with onboard SD card logging and USB communication.  The optional MS3X expansion board adds for eight channel sequential fuel and eight channel ignition control, plus tach output, boost control output, nitrous control, and more.  Assembled units are $540 without expansion board, $640 with expansion board.


Must Haves

Stimulator – This isn’t 100% required but it should be in our opinion, let’s say 98% if you’re building the ECU yourself, and 80% required (or recommended) if you’re buying a pre-assembled ECU. During kit assembly there are several sections that you complete one at a time and test the unit after each section. You will need the stimulator to be able to test the unit. After assembly, or if you buy a pre-assemble ECU the stimulator will help you to get familiar with the MegaSquirt and the tuning software before ever attempting to install the ECU on your engine. This is also an excellent tool for testing your Megasquirt ECU while you are working through building your wiring harness. If you have a problem and don’t know if it’s in your wiring of the ECU you can use the stimulator to figure that out, and if the worst happens and you see sparks fly, you can plug the ECU into the stimulator and make sure it ECU is still working properly so you know you can continue. While not an required tool it is highly recommended- we’ve seen many people come back for one with their project stalled in the meantime, and we’ve never had anyone regret buying one. If you don’t purchase a stimulator for yourself you should at least make sure you know someone who has one that you can borrow when (not if) needed.  We’ve never had anyone regret buying one, we’ve had plenty of people regret NOT buying a stimulator, and then place a second order for it.  Kits are $45, assembled stims are $69.   We also carry a power supply for it for $9. You can find it in the ‘Tools’ section of the catalog.  The JimStim carries a slightly higher price, $59 for a kit, $88 for an assembled unit, but adds the ability to simulate many types of OEM crank and cam sensors and test more outputs.  We recommend the JimStim if you’re going distributor-less with a crank trigger wheel or any patterned crank or cam trigger as the JimStim can simulate most of these patterns and allow you to test and preconfigure your ECU as accurately as possible to meet the needs of your vehicle.

Tuning Cable – You’ll need this to connect your laptop/PC to your ECU.  It’s a standard DB9 Straight-thru serial cable, meaning pin1 goes to pin1, 2 to 2, 3 to 3, etc.  If you already have one great!  If not I have them for $5.50.  You can find it in the ‘Tuning Cables’ section of the catalog.


Optional

USB-Serial Adapter – If you’re laptop has a real DB9 serial port then you don’t need this.  If not then you probably do.  Many USB-Serial adapters are very troublesome when used with the MegaSquirt and MegaTune, we tested a couple to find one that works reliably every time.  This is it and it’s priced at $22.50.  You can find it in the ‘Tuning Cables’ section of the catalog.

Relay Board and Cable – Though the Relay/Power Board is not required, it is a convenience and reduces the chance of miswiring during the installation. The relay board provides a central place for all of the required relays, fuse protection, and external wiring for the MegaSquirt ECU. If you are installing MegaSquirt in a previously fuel injected engine you may be able to reuse all of your existing relays. If you are fuel injecting a previously carbureted engine you will need to install relays for the main ECU power, Fuel Pump, and FIdle circuit. You can do this manually or you can use the Relay Board to simplify this process.  You can also build the cable yourself with the included DB37 and hood that included (one w/ the relay board, one with the ECU kit), or as the cable is kind of a pain to build I’ve made them available pre-assembled as well.  Relay Board Kit, $64; Assembled, $88.  4′ Relay Cable, $85Note that the relay cable and the wiring harness are mutually exclusive- they are not designed to be used together as once you use a relay cable you just need to run all wiring back to the screw terminals on the relay board, not a DB37 connector like the harness uses.  I have had customers buy both just to harvest the labeled/color coded automotive grade wiring after cutting the DB37 off.

Lead Bending Tool – Makes life a little easier when building out the kits as it allows you to precisely bend the leads to fit properly into the PCB.  My kit labels are marked with the proper spacing for each component eliminating guesswork.  $5.50  You can find it in the ‘Tools’ section of the catalog.

Wideband o2 Sensor/Controller – Highly useful for tuning as this will display your exact air/fuel ratio accurately so you can tune appropriately.  Narrowband o2 sensors (OE on most cars) are ONLY accurate at 14.7:1 so they are nearly useless for tuning, wideband gauges are accurate from 10:1-20:1.  I have units with and without gauges.  The LC-1 is an affordable unit at $199 that is suitable for permanent in-car installation.  You can also buy an LC-1 with a gauge; prices range from $229 to $329 depending on what gauge style you prefer.  The LM-2 at $489 has a built in display and can be used for permanent installation in a vehicle but it’s better suited to someone who plans to tune multiple cars and wants a system designed to be moved from car to car.  The LM-2 also has the ability to read two wideband sensors and data log information from an OBD-II diagnostic port on most ’96 and later cars.  Both the LC-1 and the LM-2 have dual programmable analog outputs.  You can use one to drive a gauge, and the other to feed the ECU, or just use one or the other.  It will also simulate narrowband to fool the stock ECU and prevent CEL (check engine lights).  You can also buy Innovate gauges on their own if you already have an LC-1.  You can find these in the WideBand o2 Systems section of the catalog.

Trigger WheelsMegasquirt works with many distributors and crankshaft position sensors. But if you happen to have a trigger wheel that is not compatible, or if you want to use features your original trigger wheels do not support, you can use our line of 36-1 trigger wheels for a highly accurate crank trigger setup.


Wiring and Sensors

I carry 8′ wiring harnesses for $67 that are designed to be adapted to any engine (there’s also a 12′ wiring harness priced at $85).  They are very nice and fully labeled (printed labeling on the wires) with split loom covering.  All wiring is automotive grade and the connector hood is metal.  MS3 units with MS3Xpander will need a second wiring harness; we carry a ready made one priced at $78 for a 12′ length.  Closed element IAT/CLT sensors are $17.75 with a 6″ wiring pigtail and Open Element IAT sensors (for turbo/SC apps) are $22.25 with the 6″ pigtail.  I also carry Bosch Fuel Injector connectors with 6″ pigtails for $5.75 each.  Megasquirts have a built in MAP sensor, while the Microsquirt can use a GM 3 bar MAP sensor priced at $64. The connector on the GM sensor is sold separately for $11 with a 6″ pigtail.

You can usually reuse your stock CLT sensor, and often the IAT sensor IF it’s still there when you remove the MAF/AFM. If it’s a part of the MAF/AFM then you’ll be removing that, and you’ll want to wire in a new one.

Also note that the relay cable and the wiring harness are mutually exclusive- they are not designed to be used together as once you use a relay cable you just need to run all wiring back to the screw terminals on the relay board, not a DB37 connector like the harness uses.  I have had customers buy both just to harvest the labeled/color coded automotive grade wiring after cutting the DB37 off.