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Build Your Own Fuel Injection Computer

renaissance-redneck writes "I was searching for details on assembling a fuelie setup from junkyard parts when I stumbled across this: 'MegaSquirt is an Experimental Electronic Fuel Injector Controller for Internal Combustion engines. Its main goal was to create a simple fuel-only controller that could be easily reproduced with cost-effective components.' If you've got the time and the skills, it beats spending $2000."

8 of 282 comments (clear)

  1. Please don't knock out the server.... by Juggle · · Score: 5, Informative

    Not this weekend! I build my MS back in December but didn't get my new motor together until about a month ago. Now I'm about ready to start putting it all together and /. finally notices the project.

    So of course just when I need the site the most it will probably be overrun and unavailable ;)

    Seriously though it's a great hardware hacking project. Quite a few revisions to the basic system have been made by the users and there are even a few spin-off projects (MegaSpark, MegaSquirtAVR, MegaJolt, MegaView, MegaTune, MSTWeak3k....) all of which were created by users of the system.

    It's based on a stripped down simple version of the DIY EFI-32 project that aimed at building a homebrew version of the GM computer but was getting so complex it was turning some people away.

    If the main site does get slashdotted there's the Yahoo Group: http://autos.groups.yahoo.com/group/megasquirt

    The MS FAQ:
    http://members.shaw.ca/megasquirt/MS%20FAQ.h tm

    And a few photos of my own project for those of you you just want to see the pretty pictures:
    http://www.americansandassociation.org/ phpBB2/modu les.php?set_albumName=album43&op=modload&name=gall ery&file=index&include=view_album.php

    --
    --- Juggle juggle@hitesman.com
  2. Re:Interesting... by barzok · · Score: 5, Informative
    Cadillac still has it, it's part of the Northstar system. But, it's only for use in emergencies - if you lose your coolant, it shuts down half the engine at a time to pump air through to cool it off.

    Word on the street is that Dodge's new 5.7L HEMI has or will have in a near-future iteration cylinder shutoff for when you don't need all 8 sucking down the gas.

  3. Re:Interesting... by thing12 · · Score: 5, Informative
    Cadillac still has it, it's part of the Northstar system. But, it's only for use in emergencies - if you lose your coolant, it shuts down half the engine at a time to pump air through to cool it off.

    The Cadillac 16 uses a similar engine and it switches on demand to run on 4, 8 or all 16 cylinders of its 13.6 liter engine. Very cool stuff...

  4. Other options by vsigma · · Score: 5, Informative

    They do sell other standalone setups which we use for Rallying (Yes, like you see on SpeedVision, or what you have played on GranTurismo or other Rally racing game) - examples: Link ECU, MoTec, AEM-EMS

    All of the above allow control and modification of all elements of the car via a serial link to a laptop. You can even data log and so forth.

    Depending on where you buy it and so on, it's not going to be as cheap as the product listed here - but, you gain boat loads more functionality. For Rally racing like we do - we need the control/fine tuning ability to change fuel maps, ignition timing, Anti-lag for the turbo (amongst other things) to squeeze out every bit of performance that we can to go against much better funded teams.

    -victor

  5. Re:Interesting... by ncc74656 · · Score: 4, Informative
    On an engine with sequential multipoint injection (one injector per cylender, near the intake valve), could one modify the ECU so that, when the engine is under minimal load, instead of firing the injector on every intake stroke, it would fire on every other intake stroke - in effect changing a four stroke engine into an eight stroke engine?

    That'd be more like turning your V8 into a 4-banger. Cadillac tried something like it ~20 years ago with the V8-6-4, which ended up not going over too well with drivers. (Their current Northstar V8 has a similar capability, but while the V8-6-4 used it in normal operation to try to squeeze better mileage out of a big engine, the Northstar only uses it as an emergency measure. If the engine loses coolant and starts overheating, the engine computer limits vehicle speed (to 50 mph, IIRC) and shuts down half of the cylinders at a time, cycling through them in turn so they can cool down a bit. Basically, it allows what's normally a water-cooled engine to run as an air-cooled engine long enough to get to the nearest garage and fix the problem.)

    Unless you had a way to hold the intake and exhaust valves open when you didn't want the cylinder to operate (really big solenoids, perhaps?), running each cylinder half as often would rob lots of power...you'd compress a chunk of air, but wouldn't have a combustion cycle to make any use of it. With some engines, holding the valves open would more than likely result in the piston slamming into them on the compression and exhaust strokes, which would be a Bad Thing. (My understanding is that some imports have this problem when the timing belt breaks.)

    --
    20 January 2017: the End of an Error.
  6. Close but it needs more... by Tweakmeister · · Score: 5, Informative

    The modern ECU's control more than just the air/fuel (by reading 02 sensors, etc.). They alter things like timing and monitor a host of things.

    Many in the Honda crowd use an Apex'i S-AFC (or similar) to attach in line with the computer to adjust various things. Additionally you can buy other controllers and the like to adjust realtime at will.

    This thing is impressive, but is no replacement, it's a piggyback, and has a long ways to go.

    --

    Colossians 2:8

  7. It's all been done... by BJZQ8 · · Score: 4, Informative

    Go to this link and see what people have done already. Lotsa hacking going on there...the entire GM Engine Computer has been reverse engineered. I drive a GMC Typhoon...and there are several guys on the "syty list" that have really taken apart the code, and made it possible to change all sorts of things. There is even a programmable box you can use to flip through various programs of timing and fuel.

  8. Here's some basic information by Y2K+is+bogus · · Score: 4, Informative
    The main places you want to look for MegaSquirt stuff is:

    Yahoo MegaSquirt Group This has the message archives, files, and links to MS related sites.

    MegaSquirt FAQ This is the place that you should look for answers before sending to the list. If it hasn't been asked here, Lance is more than happy to add the Q/A to the FAQ. It's very well organized and will take a novice through the whole process.

    Since Bruce and Al's site was already linked, I'll forego that link. The best place to start is the Yahoo group, since it really is the nexus.

    Just a couple of quick bits. If you are planning on using GM TBI injectors, get some 2 ohm 25 watt ballast resistors FIRST.

    Second, if you are planning on using a distributor for the tach signal, you are best off by using the hall sensor directly. A lot of VAG vehicles have reported noise problems on the tach signal.

    These are really the only 2 things I'd want to caution about first.

    All in all, the MegaSquirt is a good system for DIYers because it bypasses all of the complexity of factory systems. You can use it with most factory sensors and it performs great. One of the bread and butter applications is replacing CIS with EFI, many people have done it.

    BTW, my engine is the 1991 CBR 600 F2 engine on the IT Runs! page.