Hey guys, I have come across someone who is willing to part with a megasquirt for cheap. I just need to finish assembling it and make a harness for my car. My question is, how exactly does a standalone ECU like that do all the same things that a stock ECU does?

Do I need to pull the stock ECU's program off of it's ROM and load that into the standalone? My main concern is: will I be throwing engine codes all the time by replacing with a standalone? I know that putting a megasquirt on a 5s without going turbo might seem like a waste, but if I get it cheap enough I see no reason not to go for it. I also know that I will need a wideband, which I should be able to pick up for like 200ish.

Is anyone running a megasquirt on a 5s currently who has any advice to impart?

Also, yes I did use the search function, most of what I found was dealing with 3s motors. I will be updating this thread as I learn more about how this works so that others in the future can learn from it.

Thank you,
Nate

This post has been edited by Arsaces: Mar 7, 2012 - 1:00 PM

Read, Search, Google, Repeat. Remember, its just solenoids and coils...

It doesn't have to be 5s/3s specific.

This post has been edited by RobbMeeX: Mar 9, 2012 - 4:17 PM

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Megasquirt is pretty bare bones all things considered when it comes to programmable ecu's. it doesn't ultimately do everything a stock ecu does, but it does allow for custom fuel maps and some fairly basic ignition mapping... but it takes a lot of work to set up mechanically (for the ignition) and to tune properly.

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No. There is not a way of pulling anything off the stock ecu, or rather no practical way. Yes you will be throwing engine codes... or you would be if there was a stock ecu to throw them... and yes it is pointless and a WHOLE LOT of unnecessary work. Essentially... you run the ecu and tweak the fuel maps until the engine runs good. You should do this on a dyno with proper monitoring to ensure correct fuel ratio mixtures and to maximize gains... but this is easier said then done. You could run one as a piggy back over the stock ecu... but there still are no ultimate benefits considering you're doing this on a stock engine.

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Not on a 5S... but on a Toyota... 4AG 20V. My advice... stay away... not worth it. The stock ecu with a piggyback is infinitely better for most applications 300+ hp.

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Starting your modifications with a programmable ECU is not a smart idea. The ecu should come as your engine modifications exceed the capabilities of a stock ecu... because the ecu alone is going to make a minimal difference performance-wise.

what sensors/wires are left unused when you wire in a megasquirt?

can it use a factory knock sensor for ignition retard?

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Thank you Kwanza26, I think I just jumped the gun on the standalone thing. Someone offered me one for cheap so I wanted to see how much additional work I would be subjecting myself to.

-Nate

the MS is actually a very powerful standalone. it does the same thing the stock ECU does on running the engine. It does not monitor the engine performance like the stock ECU does. It does exactly what you tell it to do. all you need to hook up is the injectors, crank position, ignition, water temp, intake temp, MAP, and maybe O2. thats all you need to run the engine.

I don't believe my eyes when I read that a stock ECU with piggyback is better than a standalone...

That has to be the worst advice, tuning-wise, I've read.

That said, OP, like Smaay said, all you need is to figure out which pin controls what and tap into the stock harness and do it.

If you have someone who knows what they're doing, do it. I have a friend running MS-II on his 5s-fe MR2 and it's the best mod he has on his car. The thing lets you do whatever the f8(^* you want.

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That O2 is monitoring engine performance. I think you can use MS to lean your mix(mpg) or optimize timing(power). Or you can fool your ecu into working with a piggyback. You'd have lots more research if you really wanted to get it running.

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Everyone has a "friend" right ? I don't have a "friend" who did mods... i actually did them myself... so speaking from experience...

Blast from the past thread revival, sorry, I was searching megasquirt.

I gotta chime in and say that I think that adding a standalone as one of your first mods is actually a GREAT idea if you're planning on modifying a lot down the road because you now have the ability to tune for each mod that you do and can optimize everything you add. In the WRX community a way to program the ECU (the stock ecu's are re-flashable) is regarded as an absolute necessity before modifying anything else. Also, a standalone will always be better than a piggyback because a piggyback only tricks the stock ecu into doing things and will fight back every step of the way (i.e. using an SAFC to "trick" the ecu into pulling fuel also adds timing) whereas a standalone just sets fuel and timing to whatever you say. Yes, there is a steep learning curve with standalone's and especially megasquirt, but once you get everything dialed in it'll be better than just having a piggyback.

I was really searching for information on what it would take to install a megasquirt on the 5s and still keep all the creature comforts like A/C and what-not. I think a big reason why so many 5sfte set-ups have failed in the past, mine included, is from improper tuning. After owning many other cars and seeing how literally everyone else approaches tuning of a turbo, I can see that an SAFC or an emanage might be ok for a low 5-6 psi set-up but definitely should not be using it to tune the 200+ whp set-ups at all! I want to megasquirt my miata first, and then once I have the thing figured out, then try and put one on the celica

This post has been edited by 6strngs: Jul 31, 2013 - 1:42 PM