a few questions about mega squirt

eudidimuss

hello i was kicking around the idea of using megga squirt for my turbo applaction instead of using the 749 ecm.
the thing is i don't know if any people are using here? if so what are the pros and cons? any info would be great.

*edited for spelling by a moderator*

91z24 · Posted: Fri Aug 29, 2008 12:48 am Post subject:

I'm using it (megasquirt).

I even bought all the hardware to tune the stock ECM before going megasquirt. Everyone on there will tell you to keep the stock ECM, its already there and it works but nobody said they aren't able to have a proper idle and what not

Trust me, its a royal PITA to tune a stock ECM, I guess it can be done, if you have 5 years of free time or something. I tuned my megasquirt in a few hours, its not perfect yet but close enough for me (and look at my car, I'm close to being a perfectionnist, it's not a POS), so almost perfect is almost perfect.

I know Six_Shooter is about to reply use the stock ECM and have 4237428 things to say about what I just say but I don't care. Spend the 200$ and buy a megasquirt. You will never looks back, period.

Btw, the cons I could say is:

- You have to build it, you have to add output to control fan, etc, it can be a PITA to setup at first if you're not used to it but you will learn A TON and can help your friend with it after.
- And the other con is that you have to buy it and the stock ecm is already in the car but with the stock ecm, you will have to buy all the tuning crap, just the ostrich (which is not 100% needed but would really help) is the same price as a megasquirt.

Any specific info you want to know about megasquirt, just ask, I will see what I can do.

Btw, not having the stupid idle relearn anymore is the best thing that could happen in my life (ok maybe not

)

scott0999 · Posted: Fri Aug 29, 2008 7:09 am Post subject:

Six_Shooter · Posted: Fri Aug 29, 2008 7:59 am Post subject:

Where do you live?

This is a factor in deciding what to use on top of just what you would like to use.
For example, here in Ontario, the stock ECM is the easiest way to remain emmisions compliant, since the check engine light will function, and properly, which is checked when the car is taken in for an emisions test.

I have looked into using Mega Squirt, several times, and I just keep going back to the OEM GM ECM.

I recently changed my 1973 Datsun 240Z to EFI, and am currently using a '7749 ECM with code 59 (www.code59.org), the car was driveable in less than an hour, but being the perfectionist that I am spent a few hours on the jack stands tuning out the return to idle parameters. The first drive down the street was MUCH better than I thought it was going to be, almost like it was meant to be this way. Keep in mind, that my car has a Nissan inline 6 cylinder of 2.8L displacment and a rather large turbo on it. The code that I am using is modified code that was originally used on a turbo 4.3L V6.

My idle is solid varries no more than a stock engine would (about 25 RPM according to the ALDL dash).

I will admit I do have a few issues that won't tune out, or haven't had time to tune out yet, I have all of about 3 or 4 hours in the last week to "dedicate" to tuning the car, since I'm still busy with other commitments, I've been driving the car all week, in fact I haven't driven my rental all week (my DD is in the body shop, due to being backed into a couple weeks ago), since I got the Datsun running again. The issues I have are related to mechanical problems that NO EMS would be able to tune around, at least no easier than I can now. I have discovered that the Dizzy I am using does in deed have mechanical advance, this is causing havok with certain driveability conditions, I will be changing that tonight, and I believe I have a problem with cylinder #1, I haven't discovered exactly what yet, again, I haven't had much time to dig any deeper than looking at the plug, something else I plan on looking at tonight. I don't care what EMS you use, it will not tune around mechanical issues, so everything else needs to be in good operating condition in order to actually get best results.

BTW I'm only using a dizzy, because I didn't have time to get my DIS in and working, since I had a show to be at with the car on this Sunday just past, Saturday was do or die time, I did.

There have been a few times I've recommended to people that the MS would likely suit them, such as changing a car that was originally carb to EFI, the MS would be an easier retrofit then, with it's new and "flying lead" harness, a that makes it easier for a beginner to EFI to retro fit it. Learning the tuning looks like it might be a bit easier, but I haven't used MS directly, so I can't say how easy it is to tune hands on, only what I have read and seen on a few forums.

In a situation like this, where you already have the EM GM ECM installed, I would get the tuning equipment from Moates (www.moates.net) and go, there's also a few ther sources for sme equipnment, truth be knwn, I'm using a Willems E/EPROM programmer that I bought from MCUmall.com. I also have a home made ALDL cable, but have bought the Moates.net ALDL Extreme cable, because it's USB communication to the laptop.

FWIW, you don't need to even swap in a '7749 to run turbo code, there have been many people using $58 (Turbo Sunbird/Syclone/Typhoon) and $8F (TGP), in a '7730 or similar ECM, without issues. The main difference between the '7730 and the '7749 is the number of injector drivers, the '7730 has 1, the '7749 has 2, in both cases the injectors are batch fire anyway, the secnd injector driver in the '7749 is mostly for the Sunbird application that uses P&H injector scheme, though a few V8 guys have changed the sense resistors and ran 8 injectors in P&H.
I used $8F in a '7730 fr a couple years, back when I had my truck running, I didn't have the ability to tune back then, so it was stock TGP code, on a slightly different set-up than the TGP.

When I've looked at buying an MS, and compared what I would be spending I discovered for the price I would be spending on the MS, I can buy all the moates.net tuning equipment, and then some, and still be able to take that tuning equipment to someone elses car, and tune thiers for them, as many times as I would like.

One of the biggest things I don't like about the MS, is if the ECM failed and I was, say I was somewhere in the states (again I live in Ontario), I would basically be up shit creek without a paddle. I'm sure I could find someone somewhere around that either might be able to help, or possibly a replacment unit, but with all the variations, it would likely still take some serious time to make it match. With the EM GM EMS, I just go down to a local auto recycler, buy an ECM, swap over the MEMCAL, plug it in and go.
FWIW, I haven't experianced a failure of an OEM GM ECM in all the years I have been using them, thought I had a couple times, but turned out to be something else each time.

eudidimuss · Posted: Fri Aug 29, 2008 2:43 pm Post subject:

well the thing is that i have the obd1.5 bastard step child ecm, also i have the 749 ecm sitting at home. the thing is the 749 may not support my vss and maby a few other things, so i was thinking meggasquirt could control the spark and fuel on my turbo progect and later on in the future i could have it control a few other things. i know this is gonna be a huge pita but i've spent the money to put a turbo on the car. i might as mell be able to tune for better power than i can just with an fmu. i'm just gonna need help since i've never messed with the ecm before.

scott0999 · Posted: Fri Aug 29, 2008 4:38 pm Post subject:

wait what car is this on? you have obd 1.5??

eudidimuss · Posted: Fri Aug 29, 2008 5:13 pm Post subject:

94 and its a 2.2ohv

91z24 · Posted: Fri Aug 29, 2008 5:20 pm Post subject:

It should be OBD1, wouldn't it ?

zmods · Posted: Fri Aug 29, 2008 8:37 pm Post subject:

Yeah, I believe the OBD1.5 was just equipped on 95 models?

eudidimuss · Posted: Fri Aug 29, 2008 8:46 pm Post subject:

yes and no some came on late in the modle year? besides i lookes up the ecm and couldn't find anything

isaachayes · Posted: Fri Aug 29, 2008 9:07 pm Post subject:

Does the ECM have a chip you can remove or not? If it has a chip, its OBD1. If not, it's flash based OBD1".5"

Six_Shooter · Posted: Fri Aug 29, 2008 9:08 pm Post subject:

The 749, can support any GM VSS out there, the difference is in the code, not the ECM.

Code 59 (www.code59.org), is a derivitive of $58, where in the Sy/Tys it used a sine or square wave from a DRAC module. The Sunbird, that used the same code, obviously just tuned a little differently, used a magnetic VSS. code 59 has been tested with both the signal from a DRAC module and a magnetic VSS. A speedo output from the ECM directly might be a different thing altogether, since I don't know off hand if $58 or $59 has code for it. Dig or the other authors of $59 would be the guys to ask, and if it doesn't I'm sure the code could be added.

Another option, would be to use $8F (TGP), as I'm quite sure it uses a speedo output, that code will also work in a '7749.

*EDIT* I just looked at the '7749 diagrams, and in the Sunbird diagrams it has outputs for both cruise and instrument panel, so yes $59 will have these parameters imbedded.

eudidimuss · Posted: Fri Aug 29, 2008 10:24 pm Post subject:

hmm verry intresting my ecm is the 16191947, i would still have to get the ostrich for the tuning aspect correct?

cobra17st · Posted: Fri Aug 29, 2008 11:37 pm Post subject:

Did a quickie Google search for that # and found this:

eudidimuss · Posted: Sat Aug 30, 2008 9:57 am Post subject:

see thats why i am looking at meggasquirt, i have the obd1.5.

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