by Bowling and Grippo

F^requentlyA^skedQ^uestions

If you are new to the MegaSquirt^® community, there is a lot of information to digest, and much of it will seem confusing, or even contradictory. Your best bet is to read the FAQ and the manual. In general, the MegaSquirt^® family of EFI Controllers is not designed to be a 'no hassle' solution. Instead it is intended to be an educational process. As a result, a large amount of reading and study is required.

The FAQ is below, and the manual is here: MegaManual™ Table of Contents

There are a large number of considerations, options, and independent hardware paths that may suit you and your vehicle, but only you know your wants, needs, and abilities. As well, any of the family of MegaSquirt^® EFI controller are 'universal' ECUs, and it is up to the user to sort out the details for their vehicle. Others may be able to provide some help on your vehicle, try the forums at www.msefi.com for general MegaSquirt^® information and support. Some distributors (see the distributors listings) also have application specific guides.

1. What is a MegaSquirt^® EFI Controller?
2. Are MegaSquirt^® EFI controllers emission legal?
3. What do all the version numbers mean for the hardware and code(s) for MegaSquirt^® EFI controllers?
4. Where can I find the set-up parameters for my particular engine?
5. What is 'tuning'?
6. Can I have two tables, one for economy and one for power, and a switch to choose between them?
7. How can I find out more about MegaSquirt^® EFI Controllers?
8. Where can I ask questions about MegaSquirt^® EFI Controllers?
9. Is there a PDF of the manual for me to read off-line?
10. How do I order a MegaSquirt^® EFI Controller and other items?
11. How does the MegaSquirt^® EFI Controller work?
12. Can I do sequential injection with a MegaSquirt^® EFI Controller?
13. Who created the MegaSquirt^® EFI Controllers? Is it a big corporation?
14. What other hardware is there for MegaSquirt^® EFI Controllers?
15. What are the advantages and disadvantages of MegaSquirt^® EFI Controllers?
16. Can I purchase a MegaSquirt^® PCB separately? Where can I get the files to make the PCBs myself?
17. What skills, parts, and tools do I need to assemble and install a MegaSquirt^® EFI Controller?
18. Will anyone sell me an assembled MegaSquirt^® EFI Controller?
19. Do I need a PROM burner to make tuning changes?
20. What happens if I can't get my MegaSquirt^® EFI Controller to work despite advice from the forums? Am I stuck with my dead MegaSquirt^® EFI Controller?
21. What if I need ignition control as well?
22. Is anyone running a MegaSquirt^® EFI Controller right now?
23. Is there a simpler version of the MegaSquirt^® EFI Controller to only control extra injectors piggyback style?
24. Where is the FAQ for the MSx/extra code?

Q. What is a MegaSquirt^® EFI Controller?

A. The MegaSquirt^® family of EFI controllers (including MS-I™, MS-II™, MicroSquirt™, and the MS-II Sequencer™) are intended as educational projects for those who want to learn about electronic fuel injection. They are experimental Do-It-Yourself programmable electronic fuel injection controllers that you build yourself. MegaSquirt^® controllers will work on virtually any liquid fueled spark-ignition engine, naturally aspirated or boosted (up to 21 psi boost with the standard MAP sensor) as long as they are not 'pollution controlled'. Note that any MegaSquirt^® EFI controller is the controller only, you will have to gather the remaining fuel system parts yourself (from 1 to 16 injectors, sensors, fuel rails, fuel pump, etc.).

MegaSquirt^® and MicroSquirt^® controllers are experimental devices intended for educational purposes. MegaSquirt^® and MicroSquirt^® controllers are not for sale or use on pollution controlled vehicles. Check the applicable laws in your locality to determine if using MegaSquirt is legal for your application. For more information, see: www.megamanual.com/tamp.htm

Experimental means that YOU are responsible for sorting out some details of your fuel injection that are specific to your application. Do-it-yourself means that you save money by assembling it yourself with a few basic tools and comprehensive instructions.

A MegaSquirt^® EFI Controller will provide fuel control on one to 16 or more injectors, of high or low impedance, and for any number of cylinders, even three and five cylinder engines and odd-fire engines. If you have MegaSquirt-II, electronic control of number of ignition systems are supported, including: 7 or 8-pin HEI from General Motors, EDIS from Ford, TFI from Ford, or you can control a single coil directly. For fuel only control, you can trigger off the coil's negative terminal.

There are four main aspects to the MegaSquirt^® EFI Controller system:

1. Processor: You can select one of two processors (68HC908 or MegaSquirt-II). MegaSquirt-II has a faster processor, better injection pulse resolution, and has a number of added functions (like a ignition control, stepper IAC driver, and user configurable spare outputs for things like fan control or shift lights).

   The 68HC908 processor, used for MegaSquirt-I™, is a small black integrated circuit (chip) about 0.6" x 2.0".

   MegaSquirt-II™ processor upgrade (aka. MS-II™ or MS2, also used in MicroSquirt™ and MS-II Sequencer™ controllers) is a small (1.15" x 2.6") assembled PCB (printed circuit board) that plugs into the same 40-pin socket on the main board as the 8MHz 68HC908 processor, but uses the much more powerful 24MHz MC9S12C64 processor.

   MegaSquirt-II: (MC9S12C64)	MegaSquirt-I: (68HC908)

2. MegaSquirt^® DIY main board or printed circuit board (PCB): This can be based on one of four PCBs (V1.01/V2.2/V3, or V3.57). All the PCBs are similar, and all are 6.00" by 4.00" (~152.4mm x 101.6mm) but later versions have some added features that make some installations more convenient.
   

   The V3.57 board is mostly surface mount devices (SMD), and it is not a DIY board, but it is the same size and fits in the same case. There are also the MicroSquirt™ and Sequencer™ boards (see below).

3. Embedded code (aka. 'firmware' or 'code'): this is loaded onto and stored on the MegaSquirt. It must match the processor you are using. There are sometimes several options for a particular processor, for example to the standard code for the 68HC908 processor. The MS-II code can be found here. You can also check the MSx/extra code. All of the codes are free to download to upgrade older MegaSquirts.

4. Tuning software (MegaTune, TunerStudioMS, etc.): this is a Windows (or other operating system, in some cases) application that can be freely downloaded. It runs on a laptop or notebook computer, and lets the user see, adjust, and record ("datalog") the tuning parameters by 'talking' with MegaSquirt^® through the serial port (the laptop has a serial port, and MegaSquirt^® does too. A DB9 cable connects them. This part of the system, the tuning software is where you do most of your 'interaction' with MegaSquirt. The tuning software has been designed to work with any of the code/processor combinations, but you may have to configure it. Click the links above to get the lastest version.
   

There is also the stim (aka. "stimulator", or "MegaStimulator"). This essentially duplicates the engine signals that MegaSquirt^® would see in the car, letting you see if everything is working (by monitoring it with MegaTune).

There are also a number of optional components to the system:

A. No. MegaSquirt^® EFI controllers DO NOT have exemption orders, and thus are NOT emissions legal for sale or use on any on-road pollution controlled vehicles in the U.S.A. or Canada. Competition vehicles that are never operated on public roads may be able to use MegaSquirt^® EFI controllers, and some older 'non-emissions' on-road vehicles might be able to use MegaSquirt^® EFI controllers as well. For other regions, please check your local regulations to see if a MegaSquirt^® EFI controller is legal for your application. There is more information here: www.megamanual.com/tamp.htm

A. Right now there are two processors for MegaSquirt:

• 68HC908 was used on all MegaSquirt^® EFI Controllers up to 2005, and many after it. It is a discrete 40 pin IC (integrated circuit - aka. 'chip'). It will run the standard MegaSquirt^® code,

• MegaSquirt-II™ add on daughter card replaces the standard 68HC908 microprocessor and allows the controlling of ignition advance and stepper motor idle air controllers (IAC), as well as having 12x12 tuning tables (for both fuel and ignition), and a number of other features. You can find out more here: www.megamanual.com/ms2/

There are 6 versions of the MegaSquirt^® main board (PCB) in service:

• V1.01 DIY main board from the first group buy in 2001. These are no longer available,

• V2.2 DIY main board from the second group buy (2002) and all sales until July 2005 (they can be identified because they are primarily green, and have V2.2 printed in the top left corner),

• V3 DIY main board that has a number of extra features specifically designed for MS-II (V3 PCBs were released July, 2005) (they can be identified because they are primarily blue, and by the large heat sink area and the proto area grid).

• V3.57 an assembled SMD (surface mount device) board to make it easier for distributors to offer completed kits - it has the same size and functionality as the V3.00 board in most ways,

• MicroSquirt^®, a fully built ECU based on MS-II processor but entirely in SMD with a weather-proof case and connector, and

• MS-II Sequencer™, an enhanced version of the MicroSquirt^® with sequential injection and individual cylinder fuel and spark advance trim (available soon).

There are two main Bowling and Grippo base code threads right now:

• the standard V3.000 code for the MS-I 68HC908 processor, which has a basic fuel-only 'feature set',

• MegaSquirt-II™ code, that runs only on MegaSquirt-II processors and provides ignition and stepper IAC control as well as user configurable spare outputs.

There is also the MSx/extra codes for MS-I and MS-II, its FAQ is here: www.msextra.com/viewtopic.php?t=22376.

MegaSquirt-II™ (MS-II™) will work with V1.01, V2.2, V3, or the V3.57 main boards. The ease with which you can take advantage of all the features (stepper IAC for example) becomes easier with a higher numbered version of the main board, as more of the wiring is in place and just needs jumpers connected to set it up. However, it can be done on any board, it is just harder on some.

Q. Where can I find the set-up parameters for my particular engine?

A. There are a number of ways to set up the parameters, which will depend on your particular combination. First, be sure to read the tuning guides:

• MegaSquirt-I: www.megamanual.com/v22manual/mtune.htm
• MegaSquirt-II:
  • www.megamanual.com/ms2/configure.htm (configuration);
  • www.megamanual.com/ms2/tune.htm (tuning)

There are descriptions of a number of the parameters in MegaTune here: www.megamanual.com/mt28.htm

However there are a couple of ways to get 'head starts' on things like VE table, etc. One is to use the VE table generator built into MegaTune. There's more on this here: www.megamanual.com/mt28.htm#a.

The other method is to copy the setting from someone who has a similar combination of parts. You can look for similar vehicles in the 'Success story' forums here: www.msruns.com, and 'private message' the person using the button at the bottom of the post.

However, please be aware that you will have to tune the parameters, even if you are using settings from an apparently identical set-up.

Q. What is 'tuning'?

A. Tuning is an iterative process that starts with setting the general parameters (for fuel, spark advance, and air flow) to get the engine running, and continues until the engine performs optimally under all conditions (as judged by the tuner). There is much more here: Principles of Tuning

Q. Can I have two tables, one for economy and one for power, and a switch to choose between them?

A. Switching fuel maps for a single type of fuel is a "carburetorism" that you don't need with a properly tuned EFI setup (the low load part of the tune is set for economy and the high load is tuned for power; trivial with EFI, hard with carbs). The 'switch' is the throttle pedal. MegaSquirt^® can detect when you want more power (with the TPS and MAP sensors) and make the 'switch' on its own. If you've got the throttle almost closed and are cruising down the freeway, a well tuned MegaSquirt^® will lean things out for maximum fuel economy. Then when you floor it, the sensor readings change and MegaSquirt^® will go into the full power section of its tuning.

Q. How can I find out more about MegaSquirt^® EFI Controllers?

A. Read this page first, then read the manual by following the link to the table of contents, it should answer most of your questions.

Q. Where can I ask questions about MegaSquirt?

A. For even more info, or to ask questions register with one or more of the forums (you have to register with each forum separately, but you can use the same username - if available - and password for all of them)

www.msefi.com:	Educational, development, and research on the base B&G MegaSquirt® code and hardware. This was the original forums, but has been 'down-sized' considerably to make information and support easier to find.
www.msruns.com:	Success stories for users of all variants of MegaSquirt® who have successfully used a MegaSquirt® EFI Controller on their vehicle, or who want to document their MegaSquirt® project,
www.msgroups.com:	Specialized user groups based on location, application, or specific interests.
www.msextra.com:	Forum for discussing the MSx/extra feature rich user-usable code for MegaSquirt-I™ and MS-II™.
www.microsquirt.com:	Dedicated forums for MicroSquirt® users who are looking for details specifically about MicroSquirt®.

Q. Is there a PDF of the manual for me to read off-line?

A. Maybe. The manual is updated and expanded frequently, and as a result the web version is always the best source for info (and should be the first place you look for information). In some cases, some of the more stable parts of the manual have been made into PDFs, and posted here: www.megamanual.com/files/docs/.

If you want to read the manual when you do not have internet access, you can either:

• Save the current web page you want (usually 'File/Save As' in your browser) for off-line reading on your laptop, etc., using your browser, or
• Import any current web page of interest into a word processor (such as the free Open Office) and format it for your printer. With Open Office, you can open a MegaManual web page directly by entering the URL into the 'File name' text box under 'File/Open' (and you can then directly export it as a PDF file if you wish).

Q. How do I order a MegaSquirt^® EFI Controller and other items?

A.You can buy complete kits (which include everything - the PCB, programmed processor, all required electronic parts, along with the case, etc.) from MegaSquirt^® distributors that accept alternative forms of payment. Be SURE to check the Products and Services forum on www.msefi.com for information on the reputation and service of particular distributors before ordering. In general, you should be very cautious of distributors not listed below.

DIYAutoTune Offers the full line of Bowling and Grippo's MegaSquirt® Products as kits or fully assembled and ready for use. All kits are fully labeled, including everything you'll need to build your own unit. Additionally DIYAutoTune.com carries wideband o2 systems and other tuning products that integrate nicely with your MegaSquirt® Engine Management System. Same day shipping on in-stock orders received by 2pm EST.	www.diyautotune.com (websales@diyautotune.com)
Glen's Garage Glen's Garage is the original distributor of MegaSquirt® products from Bowling and Grippo. Glen's Garage sells a complete line of MegaSquirt® kits and accessories. Items in stock ship the same business day if ordered by Noon (Central time zone).	www.glensgarage.com (glen@glensgarage.com)
RS AutoSport offers professionally-assembled and tested MegaSquirt controllers enhanced for MS Extra duty, label-stamped and color-coded wire harness kits (all wires needed for an EFI conversion), sensors, connectors, and other items. They guarantee the best quality PCB assembly available, and all products carry a lifetime warranty (see site for details).	www.rs-autosport.com (sales@rs-autosport.com)
ExtraEFI.co.uk is Philip Ringwood's site (one of the authors of the MSnS-Extra code) dedicated to UK and European based sales of fully assembled and tested MegaSquirt® ECU's running the MSnS_Extra code. The ECU's include a wiring harness, RS232 communication cable and the relevant software / drawings, etc.	www.ExtraEFI.co.uk (philip.ringwood@ntlworld.com)
EFI Source is dedicated to supplying the highest quality EFI products to the performance minded automotive community. Our goal is to make programmable EFI systems affordable to everyone without sacrificing quality or functionality. We will constantly be adding new products in order to meet this goal.	www.efisource.com (info@efisource.com)
ProtoCar Electronic Corp. Offers a complete selection of MegaSquirt® products and accessories. We offer the finest quality assembled MegaSquirt® ECU’s and wiring harnesses, clearly labeled MegaSquirt® kits, and many other accessories! In addition, we offer a professional repair and upgrade service. All in-stock orders will ship on the same business day if received before 2pm EST.	www.protocar.net (sales@protocar.net)
MegasquirtPR.com En MegasquirtPR.com distribuimos sistemas MegaSquirt® para Puerto Rico y Latinoamérica. Hablamos español, te podemos ayudar. Contamos con servicio de reparación local. Ofrecemos ayuda específica para tu instalación por medio de Internet o via telefónica. Tenemos asociados disponibles para servicio de instalación y tuneo en Puerto Rico. Contamos con más de 3 años de experiencia. Tenemos disponibles accesorios racing tales como: Sistemas Wideband o2, Blowoff valves, Wastegates, Intercoolers, etc. ¡Visítanos!"	MegaSquirtPR.com (info@MegaSquirtPR.com)
MSBR A MSBR é a casa da MegaSquirt no Brasil. Seja bem vindo e tenha acesso ao que existe de melhor no mundo a preços nacionais. Venha nos conhecer!	www.MSBR.com.br (starling@msbr.com.br)

There is a listing of a number of the distributors on the forums at: www.msefi.com

Note that there are also a number of vendors selling MegaSquirt^® in other venues, such as eBay. These vendors do not all have the same level of build quality, customer service, or commitment to the MegaSquirt^® community as the distributors listed above. If you are not sure about a vendor, ask for customer feedback on www.msefi.com, and check how active a vendor is on those forums as an indication of their level of support.

A. MegaSquirt-I uses the Motorola 68HC908 microprocessor and a Motorola MAP sensor to provide electronic fuel control. The MegaSquirt-I assembly code for MegaSquirt-I is available on the MegaSquirt web site, for anyone who wishes to view or customize it. A freeware compiler for MS-I is available too, so there are no extras to buy.

MegaSquirt-II uses the MC9S12C64 processor, and the code is written in the C programming language. For more info, see:

• Code
• Hardware
• Configuration and Tuning

All MegaSquirt^® EFI Controllers use Windows9x/ME/XP-based MegaTune software for firmware reprogramming, engine monitoring, and tuning. The tuning software is freely available at no cost. Even without a computer connected, the three LEDs on the MegaSquirt case allow you to monitor injection pulses, warm-up enrichment, and acceleration enrichment at any time.

There's much more on how the MegaSquirt^® EFI Controller works here:

www.megamanual.com/v22manual/mfuel.htm

Q. Can I do sequential injection with a MegaSquirt^® EFI Controller?

A. There are two common sorts of injection:

1. Throttle body injection - usually one or two injectors for the whole engine
2. Port injection (aka. Multi-Port) - one injector per cylinder

Then there are three common modes of injection timing:

• batch - all injectors fire at once, but not timed to any specific cylinder event,
• bank - ½ the injectors fire at once, then the other ½, and so on, but not timed to any specific cylinder event,
• sequential - each injector fires at a specific point in the 4-stroke cycle for each cylinder (i.e., 8 independent timing events)

Throttle body injected cars are usually batch or bank fire, simply because of the geometry. Most port injection set-ups before the mid-1990s were bank fire as well (including GM Tuned Port Injection for the 305/350).

Sequential injection requires:

• at least as many injectors as you have cylinders, with one dedicated to each cylinder (i.e., not a 4 injector TBI on a 4 cylinder).
• as many injector drivers as you have cylinders,
• and also requires a camshaft position sensor (a crank sensor is not adequate for a 4-stroke cycle engine).

Until the MS-II Sequencer™ is released, MegaSquirt^® has just two injector drivers (that can handle up to eight injectors each).

The benefits of sequential injection are that:

• you may get slightly better mileage and lower emissions at low engine speeds,
• you can tune each cylinder's fuel amount and spark timing independently (if you know how).

The effect on maximum horsepower is general small.

However, sequential injection does not necessarily mean you are injecting into an open intake valve all the time. The intake valve is only open less than 30% of the time in a typical 4 stroke engine. Once you are trying to produce more than about 25% of maximum HP your injectors are firing for longer than the intake valves are open. If your maximum HP corresponds to a safe 80% duty cycle, your injectors are injecting well over 50% of the time on closed valves. With MegaSquirt^® EFI Controller, fuel is injected on ignition events only, and while these are loosely related to cam events, it is a complex relationship, Try to 'squirt' through an open valve under all conditions is generally a bit hopeless, because:

• fuel that is injected when the valve is closed doesn't go anywhere, it just sits near the valve vaporizing until the next time the valve opens (some OEMs deliberately squirt against a closed valve to improve vaporization). So squirting against a closed valve does not generally affect the AFR for that cylinder (though there may be a small effect on the combustion quality, good or bad, depending on the port wall temperatures, etc.)
• the valve is generally effectively open (0.050") less 300° of a 720° 4-stroke cycle (and closer to 200 for 'stock' engines). So hitting the open valve requires precise cam related timing,
• to inject the full fuel charge at high loads/RPMs through an open valve requires very, very larger injectors, about 2.5 to 4 times larger than is usually recommended,
• as the duty cycle for the injectors rises, the injectors come closer and closer to squirting all the time, and injection timing becomes irrelevant.

However, for those applications for which sequential injection is desirable to maximize idle stability and smoothness, lower emissions, and make incremental improvements to cruise fuel economy, Bowling and Grippo are working on the 'MS-II Sequencer™' for which WILL do sequential injection for up to 8 cylinders (and can be used to operate COP ignition systems as well). It will likely not be released until 2008.

Also, note that MS-II code versions 2.8+ allow the user to vary the timing of the injection, so that it doesn't necessarily coincide with an ignition event. This can help avoid spraying into the valve overlap period, etc. See Injection timing delay.

Q. Who created MegaSquirt^®? Is it a big corporation?

A. MegaSquirt^® EFI Controllers result from a project developed by and for automotive enthusiasts. It was primarily developed by Bruce Bowling and Al Grippo, who provide the printed circuit boards, programmed processors, base code, and other essential parts, such as the stimulator designed by Jeff Clarke. Other people have developed and shared helpful freeware for MegaSquirt^® EFI Controller, including:

Q. What other hardware is there for MegaSquirt^®?

A. Ancillary hardware has been developed for your MegaSquirt^®:

Q. What are the advantages and disadvantages of the MegaSquirt^® EFI Controllers? Has anyone done a feature comparison with other programmable ECUs?

A. MegaSquirt^® EFI Controllers have a number of differences from the other programmable electronic control units (ECUs) on the market:

• MegaSquirt doesn't really have any direct competition in terms of price,
• MegaSquirt requires, and develops, a number skills that other aftermarket ECUs don't require. Some would see the as a bonus, others would see it as a detriment,
• The best things about MegaSquirt^® is the experience of building it yourself and being able to repair/modify it down the road. The learning you do with MegaSquirt^® is likely to be much more extensive than with other systems,
• The MegaSquirt^® Forums is one of the better things about MegaSquirt^® EFI Controller, it has drawn contributions from a huge base of people, and helped MegaSquirt^® hardware and software development,
• Many MegaSquirt^® EFI Controller users are not very interested in other ECUs. They have had different ones, and no longer consider them viable for their own use. The other ECU's specifications and design are largely guarded, and change without notice, making it difficult to understand, upgrade, and learn from them,
• When choosing between MegaSquirt^® EFI Controllers and other programmable ECUs, there aren't standards for reporting ECU specifications, so it's sometimes hard to know what reported features are equivalent or better than someone else's,
• Many aftermarket ECUs either come with, or recommend, specific fuel supply hardware. Obviously a MegaSquirt^® EFI Controller doesn't do this, which makes an apples to apples comparison difficult. On the other hand, MegaSquirt^® EFI Controllers are fully compatible with a 'junk yard', budget approach to sourcing components.

A. No, the PCB is generally only available with the processor and MAP sensor. You can check with distributors, however.

Furthermore, we do not allow people to share or distribute MegaSquirt^® or related PCB layout files (gerber files, etc.). Instead, we encourage people to purchase a genuine B&G board(s) from a distributor. This 'single supplier' policy for PCB is because:

• It saves confusion over which PCB a user has, and every question on these forums doesn't become prefaced with "which PCB are you using?"
• We cannot assure the quality of the various PCBs which might be produced, leading to headaches for everyone (we have already seen faulty counterfeits enter the market in some cases),
• A number of us who strive to provide advice on troubleshooting and installation would have to learn the foibles and idiosyncrasies of another board,
• It encourages people to use the standard PCB so that code and hardware will work for everyone,
• The small amount of money Bruce and Al make on sale of each partial kit is reinvested into R&D on things like the MegaSquirt-II, the Precision Wideband Controller and UltraMegaSquirt, which is good for all of us,
• Finally, a number of us who have been around for a while support Bruce and Al explicitly, simply because of the tremendous efforts they have made to make this community grow. Buying their board seems like the 'right' thing to do.

MegaSquirt schematics and other layout info are provided for educational and troubleshooting purposes only. All MegaSquirt^®-related circuit design and layouts are copyright protected, and cannot be copied, modified, or used in any other manner without the express written permission of Bowling and Gripppo. Please DO NOT offer to send PCB files (gerbers, etc.) or ask others to send you PCB layout files for those items available from B&G on the www.msefi.com forums. This includes the MegaSquirt^® itself, the stim, MegaView, relay board, or flyback board. Any such messages will be removed without notice and the offender may be banned.

Also note that MegaSquirt^® and MicroSquirt^® are registered trademarks.

A. In order to make the MegaSquirt^® controller work on YOUR car, boat, chainsaw, or whatever, you will need a variety of tools, skills, and knowledge. You also need a number of fuel injection components, as a MegaSquirt^® EFI Controller is the electronic controller only. Click here for a complete list of skills, tools, and parts you NEED to install MegaSquirt.

The actual assembly of a MegaSquirt^® EFI Controller is somewhat tedious, but straight forward. There are comprehensive instructions for all phases of the assembly. For example, look here for the v3 main board instructions, and here for the stim assembly instructions. You do need to be able to solder, and you do need to be able to follow written instructions. If either of these are a problem, you should consider purchasing an assembled MegaSquirt.

Installing the MegaSquirt^® EFI Controller in a vehicle that already has EFI means you will need to consider how you will run any other devices the OEM ECU controls [such as the transmission, speedometer and other gauges, and emissions devices], how you will interface the MegaSquirt^® EFI Controller to your existing wiring harness, and whether you can reuse your existing sensors.

A. Yes. Check the 'Products and Services' advertisements by clicking the link. These distributors sell genuine Bowling and Grippo boards, kits, and complete MegaSquirt^® EFI Controllers.

A. No. You do NOT need:

• Programming skills. The .S19 embedded code for MS-I or MS-II is already written and loaded (but can be reloaded or upgraded by the user without any additional hardware other than a laptop and serial cable), and the MegaTune tuning interface is a straightforward Windows application.
• PROM burner to make tuning changes. A serial port connection allows adjustment of all the tuning parameters as well as software updates.
• Advanced electronic skills. If you can solder and follow directions, or are willing to learn, you should be able to successfully assemble MegaSquirt. You do not need to know what every component does, there is a comprehensive assembly guide for the entire assembly and testing process.
• Latest laptop computer. In fact, newer computers often do not have the serial port that is needed to communicate with MegaSquirt.

Q. What happens if I can't get my MegaSquirt^® EFI Controller to work despite advice from the forums? Am I stuck with my dead MegaSquirt?

A. Peter Florance, who runs an electronics repair business, and who is a very active and informed member of the MegaSquirt^® community, has offered to troubleshoot and repair MegaSquirt^® EFI Controllers for those in need. The fee is based on standard shop rates, with a ½ hour minimum. You can contact Peter at: peter@firstfives.org.

Q. What if I need ignition control as well?

A. If you need electronic ignition control as well as fuel control (i.e. you can't, or don't want to, run a 'standard' distributor), you can use the MegaSquirt-II daughtercard for MegaSquirt^® main boards that will run the GM 7-pin HEI, GM DIS, and Ford EDIS, as well as some others. It also has dual 12×12 VE and AFR tables, as well as an independent 12×12 spark advance table and stepper motor IAC control. You can find out more at the MegaSquirt-II site and ask questions at the MegaSquirt-II forum.

Q. Is anyone running a MegaSquirt^® EFI Controller right now?

A. Yes, thousands of people are. There is a large community of people who have got their vehicles running using a MegaSquirt^® EFI Controller, see www.msefi.com. Here are some of their success stories!

Also check Per Schroeder's Grassroots Motorsports article from their October 2005 issue, or Jeff Smith's Car Craft article on the MegaSquirt^® EFI Controller from their March 2004 issue.

A. Yes. There is much more information on how to use a MegaSquirt^® EFI Controller with a rotary engine on the MegaSquirt & Rotary Engines page.

Q. Is there a simpler version of MegaSquirt^® to only control extra injectors piggyback style?

A. You can use the standard MegaSquirt^® EFI Controller to control extra injectors.

• You wouldn't need to hook up the coolant temperature sensor, if you didn't want to, you would just set all the temperature dependent values to 100% (warm-up enrichments, cold accel enrich., etc.).
• You don't need to hook up a TPS, you can just set all the accel enrichments to 0, and hook a resistor from the input pin (#22) to ground (otherwise the CPU will see a climbing value and go to 'flood clear mode'.)
• You don't need to hook up an oxygen sensor, just set the EGO step size to 0%.
• For the air temperature sensor, you would just hook a resistor across the pin (#20) where the sensor would normally connect. This resistor could have any value from the sensor curve (in the sensor section of the manual) to approximate whatever temperature you think appropriate, or you could use a potentiometer to tune the extra fuel with a single knob.

There aren't substantial differences in between tuning a piggyback or a stand-alone, except you must remember that you are tuning added fuel over and above what the the OEM ECU is supplying, so you put zeros where you don't want extra fuel (in the VE table, accel enrichments, or wherever).

In theory, you could eliminate some components (mostly a few resistors) from the PCB if doing this, but they are generally so cheap as to not be worth the trouble of omitting.

Of course, you can retain any or all of the standard MegaSquirt^® sensors to gain additional control and tune-ability over the extra injectors.