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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."
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.
;)
h tm
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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.
And a few photos of my own project for those of you you just want to see the pretty pictures:
http://www.americansandassociation.org
--- Juggle juggle@hitesman.com
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.
Not yet - but there is a Linux based tuning program being written for it. It's still in the early stages at this time but the guy working on it has made a lot of progress the past week or two. Anyone got some good guage widgets for GTK+ they care to donate to him :)
--- Juggle juggle@hitesman.com
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...
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
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.
If all you get is the injector pulse, you can buy a system for much cheaper than $2000 US!
Blar.
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
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.
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.
How is this any different from turning valves on a bigger than design carborator? Give me a break. If you program your computer wrong, your engine won't work, but I doubt it will explode or burn up.
This project is cool. It looks like free software and so, we can imagine the much will come of it. A nice use of this will be to put fuel injection on engines that were never had it to begin with. I wonder what it and some new heads could do for my 1970 VW van.
Friends don't help friends install M$ junk.
Not exactly, although this guy seems to have gotten a TCP/IP stack onto the same chip.
The MegaSquirt uses the Motorola MC68HC908GP32, which has only 512 bytes of RAM, so it's a bit tough to get much done (you try booting your linux system with "mem=512" sometime).
If you really want to run Linux on an embedded system, you might look into uClinux on a bigger processor.
http://www.tuxrocks.com/
Actually, the MS does multitask. It uses interrupts to run timers and kick off events when the timers expire. This device uses a Motorola 68HC908, a fairly low end processor. The lowest end processor you could run linux on is the 332, which the EFI-332 uses and many GM ECMs. Really though, an MPC555 is the realistic target for such an OS. The 555 and 565 are being used by the next generation ECUs because they have lots of everything.
side note on air-fuel mixture ratios. Many people have heard that you need a mixture reation of 14.7:1. 2 important notes about this fact, first, that ratio is by mass, not volume, and so per unit volume, an engine uses thousands of gallons of air per unit of fuel. Most underestimate the amount of air needed. Second, that 14.7:1 is the stoicheometric (sp?) correct, or chemically correct mixture ratio. As in, that ratio is what should occur under lab conditions. Under real world conditions, you get your best fuel economy in the ballpark of 16:1, and your best performance in the ballpark of 12:1, which is why the farther you push that accelerator, not only do you need more fuel for more air, but the RATIO should increase, since obviously pushing the pedal further down indicates a desire for acceleration.