Can I piggyback my stock ECM using the MS II. I want it to run the fuel and ignition. Being that my car has the electronic speedo, I want to keep the stock ECM. I am pretty sure I might be able to I just want to know if there are anyone who has done that. Also, Is there somewhere I can find peoples tunes so I have a place to start.

i don't know if You can piggyback it, this question should be asked at msefi.com, as i recon it is not possible. as for tune i can help You a bit with tune, just give your full setup

best regards

I'm pretty sure you can get away with this. This would make it easier to keep your stock fan control, purge solenoid and EGR also. Definitely check msefi as WASyL has said.

On DIYautotune.com, There is an article about doing it, so I assume it is possible. But I will look more into it.

http://www.diyautotune.com/tech_arti...n_parallel.htm

As for my setup,
1991 z28
350 TPI SD
Stock cam
1.6 stamped rockers
a/c removed
smog removed
Built 700r4
Flowtech Shortys
catback exhaust

As of now it has the catback with muffler, but I am gathering parts to do the Rear mount turbo setup from the directions on Junkyardturbos.com. So if anyone has some baseline N/A and turbo tunes so I have something to start with I would greatly appreciate it.

Yes, it can be piggy backed.

You could also swap out the stock ECM for a DRAC module to run the Speedo.

Better question though is why swap in a Mega Squirt when the stock ECM is more than capable of controlling just about any engine that it's hooked to.

To tune the stock ECM is cheaper than just buying a MS, even adding in the parts to go real tme tuning with the stock ECM.

FWIW, I have a stock GM ECM running the Nissan L28 I6 in my 1973 Datsun 240Z, and have no issues with it. Most guys are swapping in MS to the Datsuns, but the GM ECM to me is far more capable.

because MS gives You more options to control like rev limit to any value (with ign or fuel cut), dwell and spark duration, battery compensation, built in WB O2 control, X-TAU and lots lots more. i have learned to tune with both MS and stock ECM and i know that MS can do a lot more and better

tuning with stock ECm is good for small mods like injectors, TB etc. but if You want real performance with full engine control than stand-alone is far more better - MS is just one of the cheapest that does the job

best regards

Hmm, I have rev limit to any value I want, Battery compensation and WBO2 fueling control, and not just logging either, full closed loop WB control, though I run in open loop, so it's not really a big deal. No idea what "X-TAU" is, I've never wanted to change dwell, and that wouldn't be controlled by the MS in a GM application using the stock ICM anyway.

Funny how people a lot of people with a lot of modifications, meaning fully built engines, and lots of power are using the Delco (GM) ECM and running well.

I have been following MS since the beginning, and comparing it to the Delco ECM, thinking that the next project will be the one that I can finally use an MS on, because they've come close to a GM ECM, but it always falls short on something, there are features that just aren't in the MS that the Delco ECM has, like Vehicle Speed input, that can be used to control boost by MPH, if you have a turbo, just being able to log vehicle speed is very helpful to tuning, proper TCC control, other variables can benefit from VSS as well, like E-fan control, etc.

I also keep reading of WAY too many people having problems with the MS, both at initial install and down the road when it randomly resets.

Install and use what you want, but the MS is in no way "more capable" at controlling an engine than the Delco ECM.

IMO the ONLY advantage to an MS, is that it can see more iginition input types, which to me is still not really an advantage, because it's not hard to adapt a GM ignition system to any engine.

X-TAU: http://www.megamanual.com/ms2/xtau.htm

well i know both and MS comes easier and giving more possibilities to set-up everything to me. maybe i havn't found everything about stock ECM, but when i was compering TPI ECM to MS it looks like MS have more stuff. MS has fan e-control, gives full control on ign (delay, spark duration etc.), TCC control, dwell (you do not need to control that, others do), nitro support, launch control, alpha-n (very usefull for ITB setups), full knock control, seprate maps for each bank of injectors, warm-up accel wizards, IAT fuel and timing correction, posibility to use two MAP sensors for better correction - i haven't found these easy or any where in stock ESM to control or use.

best regards

best regards

LOL, X-tau seems to be an over complication of a simple principle that happens naturally.

Besides that really only applies to TBI vehicles, where the manifold passes both fuel and air, MPFI, such as TPI has so little distance between the injector and valve that if any fuel was deposited on the walls it would be so little that it won't make a noticible difference in fueling. From what I've read on the principle of wet manifolds and fueling is that it is no where near as random as the MegaSquirt link you posted would lead you to believe. It tends to stay fairly consistant among temperatures and flow changes through the manifold. At higher RPM, yes the air is moving quicker through the manifold, so more fuel will be pulled off the walls, but you have to remember that the air that is passing through that runner will have fuel in it, so as the valve closes, the fuel that is in suspension will usually get deposited on the walls, "re-wetting" them as the flow stops, actually the flow reverses, due to a few other things that are happening the manifold at the same time. This need to keep the walls wet in a TBI set-up is automatically compensated for, by the tuning of the VE table(s), warm up and temperature compensation tables.

Alky/Nitrous support is available and will be in more masks for the Delco ECM, Launch control is there, Alpha-N can be used, though it hasn't really been implimented by anyone that I know of, besides, I will be running a 355 with Crower intake modified for MPFI with a GM ECM, using SD, it's not that difficult to add proper MAP sensing to an ITB intake. Knock control has been around since very early on in the Delco ECMs, MS didn't have that until very recently, I also haven't heard of any one having great success with it, because of how the sensor needs to be "tuned" or "matched" and seems to have less than desired results. I don't know of anyone with a Delco ECM that needs two banks of injectors, though there has been some discussion on possible ways to make something like that work. I know that 80 lbs/hr injectors have been used on MPFI forced induction V8s with the Delco ECM, that's a lot of fuel and potential power right there, more than most of us will ever need. Warm-up paramaters are there, IAT and CTS fueling corrections are also used by most Delco ECMs, I haven't found a need for more than one MAP sensor, other than to datalog pressure drop across an intercooler or something to that effect. SIngle MAP sensor works very well. Also if you want there are "MAP2" inputs on many of the later OBD1 ECMS, that could be utilizied, mostly for logging at this point, probably because I'm not sure anyone can really see a need for two MAP sensors.

So everything you have mention is there in the Delco ECM, or can be, depending on how you plan to impliment these parts. Modified codes (masks/bins) are available to do just about anything that would be needed to be used in a vehicle. If they aren't already available, I know people working on patches or new codes to add more functionailty.

Going back to "ignition control", when using a GM ICM, the dwell can't be altered AFAIK anyway, the GM ECM in most codes also has Latency correction to take into account delay through the ICM, some codes such as $8D has this laid out in a table based on RPM, which can make for some very finite ignition timing control. The DIS ICMs definatly can't alter the dwell on, because it is calculated within the ICM itself, and honestly, I can't say I've ever wanted or seen a need to alter the dwell.

The Delco ECM also has a Limp Home Mode as well, so that if the PROM fails (really a rarety), or something happens that needs to revert to a very basic running, it's there, I haven't seen this in the MS or anyother aftermarket EMS.

The TCC control last I checked was not based on speed, and so it could lock up at a non desired time, or not lock up at all, due to the way it is used.

Like I said use what you want, but it seems silly to me to go to a less capable, in my eyes system, that will take time and extra parts that are rarely mentioned to get to work in place or beside an ECM that is fully capable of doing what 95% of us will ever need to do, and stay emmisions compliant as well.

This discussion can go on for a long time. To each there own.

I have been running different version MS since the initial rev 1.01 board. It has never left me stranded.

Main reason I refer MS is out of the box ease of real time tuning. No add on parts to add to do real time tuning. For the '746/747 and '165 based GM system its 99% plug and play.

You are correct that TC LU is not speed based - yet.

Six_Shooter - it's looks like i need to lear even more about Delco ECM, but still i found it easier to work with MS even if it does exactly same thing

best regards

Yes, a discussion like this could go on for a long time. I just see too many people assume that the OEM ECM is "limited in capabilities" or not very tuning friendly, which is not the case at all.

You seem to be one of the lucky few that hasn't experianced random resets. I just read about that happening far too often.

Hehe, I still see it much easier to add an adaptor board where the MEMCAL is installed inside the ECM, than either re-wire the engine or make adaptor harnesses/boards and gain real time tuning. 5 minute install, compared to couple hours to several days of install, based on whether you build the MS, make or buy an adaptor or re-wire the engine harness, assuming that this is a GM vehicle that factory installed EFI. Swapping either EFI system into a non-EFI application, like I have done with a few of my vehciles now, would be about the same amount of time with either system. I've used Delco ECMs for all my EFI swaps, so far, BTW.

I do use an MS product, I have a Jim Stim on my test bench, shich I have added a couple circuits to, so that I can test my GM ECMs, new code, and just learn about how an ECM (Delco or otherwise) will react to certain changes.

I do try to keep up with MS, and like I've said I will see if the new version each time one comes out might just be the one that I can use for any of my swaps, and there's always something that is lacking, and the features it may have over the Delco ECM, usually isn't something I'd use.

I also tried MegaTuner or what ever the program was called on my laptop one time, and for some reason made my laptop lag so bad, it took about 5 minutes to try and close the program, uninstalled, and re-installed a few times, along with a few different downloads, with no improvement. So that also put a bad taste in my mouth for it. I know other people don't have that problem, but couldn't figure out what was going on with mine. I was using a decent laptop too, with 1 GB ram, 1.5 MHz PIII CPU IIRC, so it was well more than recomended specs.

I do like how the MS is open source, right from hardware to firmware, but even so, it's not that much of an attraction to me. It would have been at one time, but not so much anymore. Also most people that will be swapping in an EFI system, don't really need to be able to write new firmware, nor know how, they just want to be able to tune thier engine.

We're all trying to get the same thing here, just wanted to point out that the Delco ECM is more than capable of doing a lot of things that people assume it's not.

My understanding is that the MS & engine glitches when tuning changes are made. Which means that it isn't real time. And that not all tuning parameters can be updated in this pseudo 'real time' environment.

RBob.

The only parameters that are not tunable when the engine is running and don't need to be tuned except on first install are the static lookup tables for such inputs are coolant temp.

Fuel, spark, and AFR target tuning are made real time in RAM and I have never had glitches and/or resets during tuning.